Jefferson Salamander (Ambystoma jeffersonianum) and the Unisexual Ambystoma, Jefferson Salamander Dependent Population (Ambystoma laterale-(2) jeffersonianum): amended recovery strategy in Canada [proposed] 2023

Official title: Amended recovery strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and the Unisexual Ambystoma, Jefferson Salamander Dependent Population (Ambystoma laterale-(2) jeffersonianum) in Canada

Species at Risk Act
Recovery Strategy Series
Adopted under Section 44 of SARA

Proposed

2023

Part 1 – Federal Addition to the recovery strategy for Jefferson Salamander (Ambystoma jeffersonianum) and Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) in Ontario, prepared by Environment and Climate Change Canada

Preface

The federal, provincial, and territorial government signatories under the Accord for the Protection of Species at Risk (1996)^{Footnote 2} agreed to establish complementary legislation and programs that provide for effective protection of species at risk throughout Canada. Under the Species at Risk Act (S.C. 2002, c.29) (SARA), the federal competent ministers are responsible for the preparation of recovery strategies for listed Extirpated, Endangered, and Threatened species and are required to report on progress within five years after the publication of the final document on the Species at Risk Public Registry.

The Minister of Environment and Climate Change is the competent minister under SARA for the Jefferson Salamander and for the Unisexual Ambystoma, Jefferson Salamander dependent population. SARA section 44 allows the Minister to adopt all or part of an existing plan for a species if it meets the requirements under SARA for content (sub-sections 41(1) or (2)). This federal recovery strategy adopts the Recovery Strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and the Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) in Ontario, prepared by the Ontario Ministry of Natural Resources and Forestry in cooperation with Environment and Climate Change Canada (Part 2). This federal recovery strategy also adopts the multi-species Ontario Government Response Statement (GRS) for Jefferson Salamander and the Unisexual Ambystoma (Jefferson Salamander dependent population) prepared by the Ministry of the Environment, Conservation and Parks (Part 3). The GRS is the Ontario Government’s policy response to the provincial recovery strategy that outlines the provincial government’s goal for the recovery of the species and summarizes the prioritized actions that it intends to take and support. The Minister has prepared the federal component of this recovery strategy (Part 1), as per section 37 of SARA. To the extent possible, the federal component has been prepared in cooperation with the Province of Ontario, as per section 39(1) of SARA.

This document constitutes the federal recovery strategy required under SARA for two species, the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population^{Footnote 3}.

Success in the recovery of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this strategy and will not be achieved by Environment and Climate Change Canada, or any other jurisdiction alone. All Canadians are invited to join in supporting and implementing this strategy for the benefit of the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population, and Canadian society as a whole.

This recovery strategy will be followed by one or more action plans that will provide information on recovery measures to be taken by Environment and Climate Change Canada and other jurisdictions and/or organizations involved in the conservation of the species. Implementation of this strategy is subject to appropriations, priorities, and budgetary constraints of the participating jurisdictions and organizations.

The recovery strategy sets the strategic direction to arrest or reverse the decline of these species, including identification of critical habitat to the extent possible. It provides all Canadians with information to help take action on species conservation. When critical habitat is identified, either in a recovery strategy or an action plan, SARA requires that critical habitat then be protected.

In the case of critical habitat identified for terrestrial species including migratory birds SARA requires that critical habitat identified in a federally protected area^{Footnote 4} be described in the Canada Gazette within 90 days after the recovery strategy or action plan that identified the critical habitat is included in the public registry. A prohibition against destruction of critical habitat under ss. 58(1) will apply 90 days after the description of the critical habitat is published in the Canada Gazette.

For critical habitat located on other federal lands, the competent minister must either make a statement on existing legal protection or make an order so that the prohibition against destruction of critical habitat applies.

If the critical habitat for a migratory bird is not within a federal protected area and is not on federal land, within the exclusive economic zone or on the continental shelf of Canada, the prohibition against destruction can only apply to those portions of the critical habitat that are habitat to which the Migratory Birds Convention Act, 1994 applies as per SARA ss. 58(5.1) and ss. 58(5.2).

For any part of critical habitat located on non-federal lands, if the competent minister forms the opinion that any portion of critical habitat is not protected by provisions in or measures under SARA or other Acts of Parliament, or the laws of the province or territory, SARA requires that the Minister recommend that the Governor in Council make an order to prohibit destruction of critical habitat. The discretion to protect critical habitat on non-federal lands that is not otherwise protected rests with the Governor in Council.

Acknowledgments

This recovery strategy was prepared by Karolyne Pickett (Environment and Climate Change Canada, Canadian Wildlife Service (ECCC-CWS) –Ontario Region), with the assistance of Jennifer Thompson and Marie-Claude Archambault (ECCC-CWS–Ontario Region). This recovery strategy benefited from input, review, and suggestions from the following individuals and organizations: Krista Holmes and Lee Voisin (ECCC-CWS), the Ontario Ministry of the Environment, Conservation and Parks and the Natural Heritage Information Centre (Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry).

Acknowledgement and thanks is given to all other parties that provided comments and input to help inform the development of this recovery strategy.

Additions and modifications to the adopted document

The following sections have been included to address specific requirements of the federal Species at Risk Act (SARA) that are not addressed in the Recovery Strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and the Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) in Ontario (Part 2 of this document, referred to henceforth as “the provincial recovery strategy”) and to provide updated or additional information.

Environment and Climate Change Canada (ECCC) is adopting the provincial recovery strategy, with the exception of section 2.0, Recovery. In place of section 2.0, ECCC has established population and distribution objectives and performance indicators, and is adopting the province of Ontario’s government-led and government-supported actions listed in the Jefferson Salamander and the Unisexual Ambystoma (Jefferson Salamander dependent population) – Ontario Government Response Statement (GRS) (Part 3) as the broad strategies and general approaches to meet the population and distribution objectives.

Under SARA, there are specific requirements and processes set out regarding the protection of critical habitat. Therefore, statements in the provincial recovery strategy and Government Response Statement referring to protection of the species’ habitat may not directly correspond to federal requirements. Recovery measures dealing with the protection of habitat are adopted; however, whether these measures will result in protection of critical habitat under SARA will be assessed following publication of the final federal recovery strategy.

Recovery feasibility summary

Based on the following three criteria^{Footnote 5} that Environment and Climate Change Canada uses to establish recovery feasibility, recovery of the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population is considered technically and biologically feasible.

• Survival characteristics: Can survival characteristics^{Footnote 6} be addressed to the extent that the species is no longer at significant risk of extinction or extirpation as a result of human activity?

Yes. There are three survival characteristics of the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population that need to be addressed in order to reduce their risk of extirpation as a result of human activity: stability^{Footnote 7}, redundancy^{Footnote 8} and connectivity^{Footnote 9}. The lack of population stability in the case of both species refers to the reduction in abundance, extent of occurrence, index of area of occupancy and habitat quality that has occurred over the last three generations (33 years). As applicable to the species, redundancy refers to the number of available breeding sites (defined under section 3.1 of this federal addition). Stability and redundancy can be addressed simultaneously by preventing the loss of any breeding site from this point forward. As applicable to the species, connectivity refers to the ability of individual salamanders to reach a breeding site other than the one in which they were born. These so-called dispersal events are infrequent but necessary to allow long-term persistence of both species at a given breeding site (see explanation under section 5). It is believed that connectivity can also be addressed because the measures required to facilitate dispersal involve known habitat techniques such as habitat rehabilitation (e.g., planting of native vegetation) and removal of barriers (e.g., construction of eco-passages under roads) in areas located between breeding sites such that salamander ambulation (travel) is physically possible.

• Independence: Is the species currently able to persist in Canada independent of deliberate human interventions, and/or will it eventually be able to achieve and maintain independence in the recovered state, such that it is not reliant on significant, direct, ongoing human intervention?

Yes, although there is a high level of uncertainty because direct human intervention will need to continue in the short-term (over the next ten years), in order to address the key survival characteristics. The species’ distribution in Ontario geographically coincides with the most populated area in Canada. The extreme fragmentation and loss of natural habitat in the Golden Horseshoe region due to the ongoing expansion of large urban areas and the highway network, in combination with the magnitude of historical wetland loss, have resulted in poor stability of both populations, indices of area of occupancy that are below the threshold for Endangered for Jefferson Salamander and below the threshold for Threatened for Unisexual Ambystoma, Jefferson Salamander dependent population, as well as very low connectivity between breeding sites. In the short-term (over the next ten years), direct human intervention will need to continue and address the key survival characteristics discussed above. Examples of human interventions that will be required to address fragmentation and loss of habitat include: protection of extant breeding sites from new development and road projects; restoration and expansion of terrestrial habitat to improve the extent and quality of habitat used for foraging, hibernation and migration; restoration of corridors to connect extant breeding sites to each other and to other wetlands that could be used for breeding but that are currently unoccupied; and reduction of juvenile and adult road mortality (see sections 4-6). Successful implementation of these interventions will require continued co-operation amongst all level of government, nature conservation organizations and private landowners.

• Improvement: Can the species’ condition be improved over when it was assessed at risk?

Yes. The condition of a species refers to the combination of factors that contribute to a species’ risk of extinction or extirpation (ECCC 2020). The declines in the number of mature^{Footnote 10} individuals observed over the last three generations in both species have lead to a deterioriation of their natural condition. However, their current condition can be improved by arresting these declines, which can be achieved by implementing the human interventions (recovery actions) described under section 6 and by protecting the critical habitat described under section 7 of this federal addition. It is expected that stability, redundancy and connectivity for both species can be improved by continuing to work with the provincial government, municipalities, private landowners and nature conservation organizations to prevent the loss of breeding sites in the future, and implement recovery actions and habitat conservation measures that can improve the condition of both species.

1. COSEWIC* species assessment information

Assessment summary - November 2010

Common name: Jefferson Salamander

Scientific name: Ambystoma jeffersonianum

Status: Endangered

Reason for designation: This salamander has a restricted range within populated and highly modified areas. Over the past three generations, the species has disappeared from many historic locations and the remaining locations are threatened by development, loss of habitat and, potentially, the presence of sperm-stealing unisexual populations of salamanders.

Occurrence: Ontario

Status history: Designated threatened in November 2000. Status re-examined and designated Endangered in November 2010.

* COSEWIC: Committee on the Status of Endangered Wildlife in Canada

Assessment summary - May 2016

Common name: Unisexual Ambystoma – Jefferson Salamander dependent population

Scientific name: Ambystoma laterale - (2) jeffersonianum

Status: Endangered

Reason for designation: These unusual unisexual salamanders occupy restricted areas within populated and highly modified areas of Ontario and depend on an endangered sperm donor species, Jefferson Salamander (Ambystoma jeffersonianum), for recruitment. The salamander faces numerous threats from human activities, leading to habitat loss and fragmentation, making its continued existence precarious.

Occurrence : Ontario

Status history: Designated endangered in April 2016.

2. Species status information

The Jefferson Salamander occurs in Canada and the U.S. The provincial recovery strategy states that the Canadian population of each species likely represents 1 to 3 % of their global abundance. Its global status was last reviewed in 2001 and was ranked ‘Apparently Secure’ (G4) (NatureServe 2022). At the national scale, it is ranked as ‘Imperiled’ (N2) in Canada and ‘Apparently Secure’ (N4) in the United States. At the sub-national level, it is ranked as ‘Imperiled’ (S2) in Ontario, and varies from ‘Imperiled’ to ‘Secure’ across its range in the United States (Appendix B).

The Unisexual Ambystoma, Jefferson Salamander dependent population, referred to henceforth as the “dependent Unisexuals”, also occurs in both countries. Its classification is pending final recognition by NatureServe^{Footnote 11} and as such, its global status (last reviewed in 2002) is considered ‘Not Applicable’ (NatureServe 2022). In its database, NatureServe currently refers to the dependent Unisexuals as “Ambystoma jeffersonianum x laterale, jeffersonianum genome dominates” (NatureServe 2022). At the national scale, it is ranked as ‘Imperiled’ (N2) in Canada and ‘Not Ranked’ (NR) in the United States. At the sub-national level, it is ranked as ‘Imperiled’ (S2) in Ontario, and has a variety of ranks across its range in the United States (Appendix B).

The Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population were listed as Endangered^{Footnote 12} on Schedule 1 of SARA in June 2017 and August 2021, respectively. Both species are also listed as Endangered^{Footnote 13} under the Ontario Endangered Species Act, 2007 (ESA).

3. Species information

3.1 Species population and distribution

Number of breeding sites

Jefferson Salamanders and dependent Unisexuals emerge from hibernation in early spring and migrate to wetlands^{Footnote 14} where they breed over the span of a few days (see the provincial recovery strategy for more details). Following this brief reproductive season, adults emerge from the wetlands and remain in the surrounding forests to forage before returning to their hibernation sites in autumn. Given their life cycle, it is useful for conservation planning purposes to enumerate the number of wetlands known to be used for breeding by the species; consistent with the provincial recovery strategy, they are defined as “breeding sites”^{Footnote 15} in this federal addition. Known breeding sites can be in the form of a discrete pond, or a swamp. In the case of swamps, the location of the specific depressions that hold water sufficiently long to allow successful larval development may vary from year to year, according to climatic conditions. A breeding site consists of all ponds (or in the case of a swamp, all depressions) located within 1 km of each other.

The provincial recovery strategy reported that a total of 40 breeding sites have been documented for Jefferson Salamander, 28 of which were confirmed extant between 1997 and 2017. Since then, one new breeding site has been recorded (in 2018, in Chatham-Kent County), bringing the total number of extant breeding sites to 29.

With respect to dependent Unisexuals, the provincial recovery strategy reported that 83 breeding sites have been documented for dependent Unisexuals, 53 of which were confirmed extant between 1997 and 2017.

Population size

The population size (N) in Ontario of the Jefferson Salamander, and that of the dependent Unisexuals, has been estimated to be less than 2,500 and less than 10,000 mature individuals, respectively (COSEWIC 2010, 2016). No new studies on population abundance for either species in Ontario have been found in the peer-reviewed literature since the publication of the provincial recovery strategy. However, extrapolations of the minimum number of adults known to be alive during one breeding cycle from select sites (which would invariably underestimate actual subpopulation abundance) yield numbers that are in the same order of magnitude as the above coarse estimates. For instance, the average number of adults captured per breeding site is 44 for Jefferson Salamander and 139 for dependent Unisexuals, based on values in Table 4 of the provincial recovery strategy^{Footnote 16}. According to these numbers, abundance in Ontario would total 1,276 Jefferson Salamander adults (44 x 29 sites) and 7,367 dependent Unisexuals (139 X 53 sites).

Ontario population size estimates for both species vary by as much as one order of magnitude when they are derived from data collected on other Ambystoma species in the U.S. For example, the estimated number of breeders per generation (N_e)^{Footnote 17} reported in the scientific literature ranges from 30 to 123 individuals, depending on the salamander species (Funk et al. 1999, Savage et al. 2010, Wang et al. 2011). When applying an N_e/N ratio correction factor^{Footnote 18} to the above range of N_e values, and assuming a proportion of 33% Jefferson Salamanders to 67% dependent Unisexuals (unpublished data referred to in Van Drunen et al. 2021), the resulting estimate for the number of adults per breeding site ranges from 6 to 135 for Jefferson Salamander and 12 to 275 dependent Unisexuals^{Footnote 19}. Hence, total abundance of mature individuals in Ontario would range from 174 to 3,915 for Jefferson Salamander and from 636 to 14,575 for dependent Unisexuals.

A significant limitation to both methodologies for estimating abundance is that the likely positive correlation between the size of a breeding site and salamander effective population size is not taken into account (Wang et al. 2011). This highlights the importance of collecting data on the size of breeding sites when assessing abundance.

Clearly, a robust estimate of population size based on empirical evidence remains a knowledge gap. However, the estimates above suggest it is unlikely that abundance per breeding site for either species ever exceeds 250 mature individuals.

3.2 Habitat

New information on the habitat use and movements of Jefferson Salamander and dependent Unisexuals has become available since the publication of the provincial recovery strategy and is summarized below.

Habitat use

A study conducted in Ohio provides evidence of differences in ecological niches between Jefferson Salamanders and dependent Unisexuals (Greenwald et al. 2016). The authors found a higher proportion of Jefferson Salamanders relative to dependent Unisexuals at breeding sites that had sandier soils, warmer average annual temperatures, higher average annual precipitation, and that were surrounded by more intact forest. These habitat parameters were described in the study as characteristics of better quality habitat, leading the authors to suggest that dependent Unisexuals may be relegated to “marginal” habitats. This may be a relevant to consider when planning improvement and rehabilitation of habitat for the purposes of recovery (see sections 5 and 6 of this addition).

Seasonal migration

Consistent with previous findings reported by Beriault (2005), a recent study conducted in Ontario found that 95% of adult salamanders overwintered in terrestrial habitat located within 274 m (for Jefferson Salamanders) and 130 m (for dependent Unisexuals) of the waterbody they had used for breeding the preceding spring (Van Drunen et al. 2020). The average distance travelled from the water’s edge to an overwintering refuge was significantly greater for Jefferson Salamanders than dependent Unisexuals Individual salamanders arrived at their overwintering location between early October and early December, with a peak occurring the first week of November (Van Drunen et al. 2020).

Dispersal distance in juveniles

Information on the autumn movements of juvenile Jefferson Salamanders and their dependent Unisexuals has become available since the publication of the provincial recovery strategy. Van Drunen et al. (2021) report that the majority (71%) of newly metamorphosed juveniles captured during each study period (ending in late October when overwintering begins) were found within 40 m of their natal pond’s edge. The study also found a positive relationship between size (measured as snout-vent length) and dispersal distance. Together these results support the hypothesis that most long-distance dispersal movements are undertaken by individuals that are at least one-year old (only 2% of metamorphs traveled more than 100 m in the above study). Secondly, and in contrast with reported differences in ecological niche and migration movements between adult Jefferson Salamanders and adult dependent Unisexuals (see above), Van Drunen et al. (2021) did not detect differences in the dispersal distance of juveniles between the two species.

An additional study reports dispersal distances that are consistent with previous findings according to which breeding sites that are separated by more than 1 km are occupied by separate subpopulations. Crawford et al. (2016) found significant genetic differentiation between Jefferson Salamanders occurring in separate wetland only when these were separated by more than 1 km. The study’s results demonstrate the need for connectivity between breeding sites to preserve genetic diversity and the importance of protecting forested habitat beyond the immediate vicinity of breeding sites in order to allow successful immigration of individuals to breeding sites where subpopulations are declining or extirpated.

4. Threats

4.1 Description of threats

This federal addition provides updated information on the threats to Jefferson Salamander and dependent Unisexuals that are described in section 1.6 of the provincial recovery strategy (Part 2), as well as new information on emerging threats for which the current impact is unknown. The new information does not warrant adjusting the impact ranking of threats provided in COSEWIC (2016), however it reveals new knowledge gaps that can be addressed under the recovery measures refered to under section 6 of this federal addition.

The provincial recovery strategy identifies the following as threats to the species: residential and commercial development; energy production and mining; transportation and service corridors; agriculture and aquaculture; invasive and problematic species; climate change and severe weather; biological resource use; and human intrusions and disturbance. COSEWIC has also identified pollution as a threat to Jefferson Salamander and dependent Unisexuals (COSEWIC 2016, 2010). The corresponding threat categories as identified under the International Union for Conservation of Nature (IUCN) and the Conservation Measures Partnership unified threats classification system (Version 2.0) have been added in parentheses after each threat sub-heading.

Residential and commercial development (IUCN threat 1.)/ Energy production and mining (IUCN threat 3.)/ Transportation and service corridors (IUCN threat 4.)

Development continues to be the major threat to Jefferson Salamander and dependent Unisexual. According to recent statistics, the human population of the Greater Golden Horseshoe, which overlaps with the core part of the species’ range, is predicted to grow by 65%, from approximately 9 million in the late 2010s to 14.87 million by 2051 (Ministry of Municipal Affairs and Housing (MMAH) 2020). Development is to be directed to existing settlement areas to promote intensification, including the Region of Waterloo (713% projected human population increase) and the Region of Halton (100% increase). Approximately half of the species’ breeding sites are located within these two Urban Growth Centers. The associated increased demand for aggregate extraction near to these development areas (which leads to the creation of new extraction sites, or expansion/intensification of existing sites), and road network expansion (MMAH 2020) compound the threat from development. Likewise, greater movement of people and goods will result in the expansion of road and railway networks, likely increasing the severity of road mortality and population fragmentation. Specifically, there are future transportation and high-speed rail corridors conceptualized to run through the escarpment area of Halton region, which contains a high density of Jefferson Salamander and dependent Unisexuals breeding sites; these developments would likely have a negative effect on habitat connectivity.

Invasive and other problematic species, genes and diseases (IUCN threat 8.)

Invasive species

The provincial recovery strategy suggests that introduced zooplankton may affect salamanders’ prey base, however current information suggests that the zooplankton are unlikely to enter the waterbodies where Jefferson Salamander and dependent Unisexuals breed because these are usually disconnected from the lacustrine systems in which invasive zooplankton, such as spiny waterfleas and fishhook waterfleas, are found (MNDMNRF 2021). Their introduction would be contingent on fish introduction or major hydrology/habitat alterations causing connection of breeding habitat to waterways where the zooplankton occur. Invasive waterfleas are currently not found in non-lacustrine inland areas of Ontario in the range of Jefferson Salamander and dependent Unisexuals (EDDMapS 2021).

The provincial recovery strategy also mentions the potential for the invasive European Reed (Phramites australis ssp. australis) to negatively affect the species due to its ability to displace native vegetation by growing in dense stands along wetland edges (Nichols 2020). Whether European Reed is having an actual impact on the species remains unknown at this time.

The Emerald Ash Borer (EAB) (Agrilus planipennis) is a non-native beetle that feeds on the leaves of Ash trees (Fraxinus sp.) to such an extent that it leads to the death of the trees. EAB is present in the Ontario range of Jefferson Salamander and dependent Unisexuals (EDDMapS 2021) and has been predicted to negatively affect salamanders by reducing canopy cover (which in turn lowers the quality of breeding habitat; Hossie 2018) and decreasing leaf litter depth (which may increase risk of predation for Ambystomatid salamanders (Myette et al. 2019). Youngquist et al. (2017) discuss the possible consequences of Black Ash (Fraxinus nigra) tree defoliation and death on wetland amphibian communities, highlighting possible impacts to wetland hydroperiod, canopy cover and litter input. The impact of ash tree defolation by EAB on Jefferson Salamanders and dependent Unisexuals specifically is unknown and is likely to be determined by site-specific conditions.

Amur Honeysuckle (Lonicera maackii) is a non-native, shade tolerant shrub that can grow up to 6 m tall. It has been reported in several locations within the range of Jefferson Salamander and dependent Unisexuals (EDDMapS 2021). Because the plant can grow in a variety of habitats including disturbed forests, thickets and grasslands (Tassie and Sherman 2014), it could become established in the terrestrial portion of salamander habitat, especially where breeding sites are located within open canopy cover habitat. Exposure to Amur Honeysuckle leaves reduced larval survival of Northern Cricket Frog larvae (Acris crepitans, Robison et al. 2021) and American Toad tadpoles (Anaxyrus americanus), but not that of Spotted Salamander larvae (A. maculatum) (Watling et al. 2011). Whether the plant is having an impact on Jefferson Salamander and dependent Unisexuals is unknown.

Diseases

New information regarding the potential for emerging pathogens to constitute a threat to Jefferson Salamanders and dependent Unisexuals has become available since the publication of the provincial recovery strategy.

Ranaviruses, a group of viruses that have been detected in over 100 species of amphibians, can cause severe disease and death of infected individuals to the point of population collapse (see review in Earl et al. 2016). Consistent with ranavirus-associated larval die offs reported in Jefferson Salamanders by Brunner et al. (2011) in New York, a recent study from Illinois has found that ranavirus also leads to mortality in Unisexual Ambystoma (Adamovicz 2019). Although ranavirus has been detected in Ontario within the range of Jefferson Salamander and dependent Unisexuals (Brunner et al. 2021), none of the reported infections originated from salamanders. The impact of this pathogen to the Canadian population of the species is unknown at this time.

Batrachochytrium salamandrivorans (Bsal), a salamander-specific chytrid fungus native to Asia, has become widespread in the European salamander trade (Fitzpatrick et al. 2018; Sabino-Pinto et al. 2018). While some ambystomatid salamanders^{Footnote 20} exhibit resistance to chytrid fungi (Pereira and Woodley 2021), Bsal infection can still elicit stress response and hinder growth (Barnhart et al. 2020). Though it has yet to be detected in North America (both in the wild and in the pet trade; Klocke et al. 2017), the risk of introduction in southeastern Canada is considered high based on habitat suitability modelling (Carter et al. 2021). In response to this threat, the federal government amended the Wild Animal and Plant Trade Regulations in May 2018 to prohibit the import of all species of the order Caudata^{Footnote 21} unless authorized by a permit issued by Environment and Climate Change Canada.

Batrachochytrium dendrobatidis (Bd), the chytrid fungus that occurs worldwide and that is associated with numerous frog and toad declines (see review in Talley et al. 2015), can infect Jefferson Salamander (Brodman and Briggler 2008) but does not appear to negatively affect triploid Jefferson Salamander-dependent Unisexual Ambystoma (Adamovicz 2019). Bd is present in the Ontario range of Jefferson Salamander and dependent Unisexuals (McMillan et al. 2019), but its impacts on the species are presently unknown.

Infections from two other pathogens not mentioned in the provincial recovery strategy have been reported in Illinois: the trematode parasite Clinostomum marginatum in Jefferson Salamander (McAllister et al. 2010, Kuhns and Crawford 2008); and, parasites of the genus Dermotheca in triploid Jefferson Salamander-dependent Unisexual Ambystoma and in Small-mouthed Salamander (Adamovicz et al. 2020). There is currently, however, no information on whether these parasites are infecting Jefferson Salamander and dependent Unisexuals in Canada.

Pollution (IUCN threat 9.)

The provincial recovery strategy mentions road salt and agricultural run-off as threats to Jefferson Salamanders and dependent Unisexuals. Although the impact of various pollutants on either species remains poorly understood, the following section provides updated information on substances that have the potential to negatively impact the species.

Perfluoroalkyls and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) are not discussed as threats in the provincial recovery strategy. They are widespread, persistent environmental pollutants that negatively affect wildlife and human health and may enter an ecosystem via agriculture and packaging (Tornabene et al. 2021, Government of Canada 2021). Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are PFAS that are toxic to Jefferson Salamander and other amphibians (Tornabene et al. 2021); these substances are prohibited by regulations in Canada, and the federal government is undertaking further action to address PFAS as a class (Government of Canada 2021).

Artifical Light

Recent studies present evidence that artificial nighttime light, particularly from roads, may negatively affect Jefferson Salamander and dependent Unisexuals. For instance, light pollution was found to alter microhabitat selection in the Unisexual Blue-spotted Salamander, a close relative to Jefferson Salamander and dependent Unisexuals (Feuka et al. 2017). Artifical light also acted as a lure for some species of vernal pool amphibians (Antonishak et al. 2017).

Copper and nitrites

Agriculture-derived pollutants that have recently been confirmed to be toxic to Ambystomatid salamanders include copper (Weir et al. 2019) and nitrites (Kroupova 2016).

Microplastics

The prevalence of environmental contamination from microplastics has garnered an increasing amount of attention from the scientific community over the last ten years (see review in Prokić et al. 2021). Microplastics, commonly refering to plastic debris less than 5mm in size, have been detected in air, water, and soil (especially agricultural fields) throughout the world (Prokić et al. 2021). There are several pathways by which microplastics may enter small inland waterbodies, including agricultural runoff, atmospheric deposition, sewage/effluent, and plastics breakdown (Hu et al. 2020). In southern Ontario wetlands, agriculture is a prominent source of microplastics due to the use of polymer beads for controlled release of pesticides and fertilizers (Balsdon 2018); These microplastics have been found in wetlands within the Ontario range of Jefferson Salamander and dependent Unisexuals.

Prokić et al. (2019) identify amphibians as highly sensitive organisms owing to their biphasic and multi-stage life history. Microplastic intake has been found to have a variety of adverse effects on amphibians (Boyero et al. 2020, da Costa Araújo et al. 2020a, 2020b, da Costa Araújo and Malafaia 2020, Malafaia et al. 2021).

Climate change and severe weather (IUCN threat 11.)

The provincial recovery strategy indicated that the impact of climate change on Jefferson Salamanders and dependent Unisexuals was unknown at the time of publication. A recent assessment of the vulnerability to climate change of some Great Lakes Basin species (Brinker et al. 2018) now provides more certainty that climate change will increasingly pose a threat to both salamander species. Based on results obtained for Spotted Salamander (Ambystoma maculatum), whose range in Ontario overlaps with that of Jefferson Salamander and dependent Unisexuals, the mean annual temperature across the entire range of Jefferson Salamander and dependent Unisexuals in Ontario is projected to increase by at least 2.53 ºC by 2050 (Brinker et al. 2018). Because this temperature increase is not projected to be offset by increases in precipitation, it will likely decrease the availability, or shorten the hydroperiod, of freshwater wetlands used for breeding by both species. The Spotted Salamander was assessed as ‘Moderately Vulnerable’^{Footnote 22} to climate change under this assessment due to four factors that also apply to Jefferson Salamander and dependent Unisexuals: prevalence of anthropogenic barriers to movement within the species range (defined as large areas of intensive urban development and agricultural lands), limited dispersal capability, and predicted sensitivity to increases in temperature and climate moisture deficit (Brinker et al. 2018). Modelling for the U.S. Midwest has also predicted significant loss of suitable habitat for Jefferson Salamander in that region due to climate change (Struecker and Milanovich 2017).

In addition, increasing air temperatures during the breeding season may alter the composition of Unisexual Ambystoma populations^{Footnote 23}, because individuals of higher ploidy are produced at higher air temperatures (Teltser and Greenwald 2015). Changes to population composition may affect population recruitment and fitness due to potential differences in survival and fitness between individuals according to ploidy levels (Teltser and Greenwald 2015, Van Drunen et al. 2021).

Climate change may also compound the threat of some pathogens to amphibians via increased temperature. Rollins-Smith (2020) suggests that elevated temperatures may decrease immune function, worsening chytrid infection outcomes, or that chytrid infection may render amphibians more susceptible to higher temperatures. Kohli et al. (2019) additionally link drought conditions, which may include reduced breeding pond hydroperiod, to reduced immune function and poorer disease outcomes in amphibians.

5. Population and distribution objectives

Under SARA, a population and distribution objective for the species must be established. Consistent with the provincial government’s goal for the recovery of the species stated in Ontario’s Government Response Statement (Part 3), Environment and Climate Change Canada’s population and distribution objective for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada is to lower the risk of extirpation of both species by:

1. arresting the decline in the total number of mature individuals of each species
2. maintaining the current number of extant breeding sites (as defined in this federal addition), that are used by either one or both species
3. maintaining, and where technically and biologically feasible, increasing the current Index of Area of Occupancy (IAO) of each species

COSEWIC evaluated the status of both salamanders as Endangered because of an inferred reduction of more than 50% in the total number of mature individuals over the last 3 generations (33 years), based on the observed reduction in the number of breeding sites and on the observed decline in EOO, IAO and quality of habitat.

Preventing the loss of any extant breeding site will, by definition, arrest the decline in EOO, IAO and number of locations^{Footnote 24} for both species; it is also the most efficient way to arrest the inferred decline in the number of mature individuals.

Improvements to the species’ stability^{Footnote 25} and redundancy^{Footnote 26} that would ensue from an increase in the IAO will further contribute to lowering their risk of extirpation in Canada. Improvements to both survival characteristics can be achieved by: improving the habitat quality of existing breeding sites and nearby unoccupied wetlands; improving the terrestrial habitat surrounding breeding sites; and, restoring habitat within terrestrial dispersal corridors linking extant breeding sites to as of yet uncolonized wetlands that could be used for breeding.

Both species of salamanders share the same population and distribution objectives given that, as the name suggests, dependent Unisexuals are dependent on Jefferson Salamander males to successfully reproduce, because eggs laid by the all-female dependent Unisexuals will only develop if exposed to sperm from Jefferson Salamanders (see full description of reproductive biology in Bogart 2019). By not having to expend energy producing males, it is hypothesized that over time, dependent Unisexuals will outcompete Jefferson Salamanders to the point of the latter’s extirpation, which would invariably lead to the subsequent extirpation of the dependent Unisexuals themselves. Therefore, constant immigration of Jefferson Salamanders into breeding sites used by dependent Unisexuals and Jefferson Salamanders is necessary to allow long-term persistence of both species at those breeding sites.

The distance separating breeding sites is therefore highly relevant to the salamanders’ persistence in Canada: the requisite on-going immigration of Jefferson Salamanders from their natal breeding site to other breeding sites used by dependent Unisexuals can occur only if the breeding sites are located within Jefferson Salamander’s dispersal capability (which is a function of distance and presence of habitat suitable for dispersal^{Footnote 27}). Given that many breeding sites are separated by distances greater than the species’ estimated maximum dispersal capability of 1 km (Bériault 2005), connectivity^{Footnote 28} must be improved so that the species can persist in a recovered state without relying on direct, on-going human intervention. Connectivity can be improved by restoring habitat within terrestrial dispersal corridors linking extant breeding sites to one another.

6. Broad strategies and general approaches to meet objectives

The government-led and government-supported actions from the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) – Ontario Government Response Statement(Part 3) are adopted as the broad strategies and general approaches to address the threats and meet the population and distribution objectives for the species. Environment and Climate Change Canada is not adopting the approaches identified in section 2.0 of the Recovery Strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) in Ontario (Part 2).

Approaches to recovery for both species involve working in collaboration with municipalities, provincial government ministries and agencies, local communities, private landowners and conservation organizations to: conserve all extant breeding sites; improve the quality and increase the extent of habitat used by the species; establish dispersal corridors that connect breeding sites to each other and to non-occupied suitable wetlands; assess the risk to the species from potential/emerging threats, and; mitigate road mortality.

Given the requisite presence of Jefferson Salamander to maintain the persistence of dependent Unisexuals, it is important to determine whether Jefferson Salamander is no longer present, or simply not yet detected, at those breeding sites where only dependent Unisexuals have been recorded (see section 3.1). If Jefferson Salamander are extirpated from a breeding site used by dependent Unisexuals, the latter will also become extirpated from the breeding site if immigration of Jefferson Salamander is currently precluded (Bogart 2019). Therefore, an additional recovery measure consists of investigating the potential need for, and feasibility of re-introducing Jefferson Salamanders in breeding sites from which they may have been extirpated but that are still being used by dependent Unisexuals.

7. Critical habitat

7.1 Identification of the species’ critical habitat

Section 41(1)(c) of SARA requires that recovery strategies include an identification of the species’ critical habitat, to the extent possible, as well as examples of activities that are likely to result in its destruction. Under Section 2(1) of SARA, critical habitat is “the habitat that is necessary for the survival or recovery of a listed wildlife species and that is identified as the species’ critical habitat in the recovery strategy or in an action plan for the species”. A primary consideration in the identification of critical habitat is the amount, quality, and locations of habitat needed to achieve the population and distribution objectives.

Identification of critical habitat is not a component of provincial recovery strategies under the Province of Ontario’s ESA. Under the ESA, when a species becomes listed as endangered or threatened on the Species at Risk in Ontario List (Ontario Regulation 230/08), it automatically receives general habitat protection unless protections are temporarily suspended through a Minister’s order. A habitat regulation can be made to define a species' habitat and many describe features (e.g., a creek, cliff, or beach), geographic boundaries or other unique characteristics. The habitat regulation (Ontario Regulation 832/21) is a legal instrument that prescribes an area that will be protected as the habitat of the species by the Province of Ontario. The regulation is dynamic and automatically in effect whenever the description(s) of the regulation are met within a specified geographic area. Following the completion of the provincial recovery strategy for the Jefferson Salamander, a provincial habitat regulation for Jefferson Salamander^{Footnote 29} was developed and came into force on 18 February, 2010. In addition to automatic habitat protection, the habitat of the Unisexual Ambystoma (Jefferson Salamander dependent population) is also protected under the habitat regulation for Jefferson Salamander, the species upon which it depends. The identification of critical habitat for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in this federal addition is based on components of the habitat regulation to promote consistency between the federal SARA and the provincial ESA to protect the species and its habitat on federal and non-federal lands.

Critical habitat for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada is identified as the extent of biophysical attributes (see Section 7.1.2) wherever they occur within the areas described in Section 7.1.1 (Appendix A).

It is recognized that the critical habitat identified below is insufficient to achieve the population and distribution objectives for the species. A schedule of studies (Section 7.2) has been developed to provide the information necessary to complete the identification of critical habitat that will be sufficient to meet population and distribution objectives. The identification of critical habitat will be updated when the information becomes available, in a revised recovery strategy. For more information on critical habitat identification, contact Environment and Climate Change Canada – Canadian Wildlife Service at RecoveryPlanning-Planificationduretablissement@ec.gc.ca.

7.1.1 Areas containing critical habitat

Recovery of the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada depends on the persistence of the species in an area greater than that which is currently occupied by individuals of the species (see population and distribution objectives under section 5). Critical habitat identified in this recovery strategy therefore includes areas that are currently occupied by the species, and areas that could become occupied by the species based on the salamanders’ dispersal capability. The size-related attributes of the critical habitat components described below were informed by published estimates of post-breeding migration distances for the species (Semlitsch 1998, Faccio 2003, Bériault 2005, Hoffman et al. 2018, Van Drunen et al. 2020).

The area containing critical habitat for Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population consists of:

1. a wetland, including a pond or vernal or other temporary pool where the presence of one or more Jefferson Salamander or Unisexual Ambystoma, Jefferson Salamander dependent population individual has been recorded^{Footnote 30}
2. an area that provides suitable foraging, dispersal, migration or hibernation habitat for Jefferson Salamander or Unisexual Ambystoma, Jefferson Salamander dependent population individuals and that is within 300 m of habitat described in 1
3. a wetland, including a pond or vernal or other temporary pool that provides habitat suitable for breeding by Jefferson Salamander or Unisexual Ambystoma, Jefferson Salamander dependent population individuals and that is within 1 km of an area described in 1., and
4. areas that provide suitable dispersal habitat for Jefferson Salamander or Unisexual Ambystoma, Jefferson Salamander dependent population between an area described in 1. and an area described in 3

7.1.2 Biophysical attributes of critical habitat

Within the areas described under 7.1.1., critical habitat is identified where the following biophysical attributes occur:

7.2 Schedule of studies to identify critical habitat

7.3 Activities likely to result in destruction of critical habitat

Understanding what constitutes destruction of critical habitat is necessary for the protection and management of critical habitat. Destruction is determined on a case by case basis. Destruction would result if part of the critical habitat was degraded, either permanently or temporarily, such that it would not serve its function when needed by the species. Destruction may result from a single activity or multiple activities at one point in time or from the cumulative effects of one or more activities over time, and can occur at a variety of scales and in both aquatic and terrestrial habitats. It may occur from an activity taking place either within or outside of the area containing critical habitat and it may occur in any season of the year. The distance away from the area’s boundary where the activity is taking place is site-dependent and will vary according to the hydrological regime and vegetation cover at the landscape scale. Within the area containing critical habitat, activities may affect breeding sites and the areas within 300 m of breeding sites that provide suitable conditions for foraging, dispersal, migration or hibernation (i.e., the areas described in Table 1). All breeding sites constitute critical habitat regardless of their hydroperiod in a given year, which can vary based on climatic conditions. Activities within an area containing critical habitat may also affect travel corridors that connect breeding sites (i.e., areas that can be used for migration and dispersal, described in Table 1). Because the biophysical attributes of habitat used for migration and dispersal are not identical to those defining habitat for breeding, foraging and overwintering, certain activities that are likely to cause destruction of breeding sites may not cause destruction of dispersal habitat. It should be noted that not all activities that occur in or near critical habitat are likely to cause its destruction.

Activities described in Table 3 are examples of those likely to cause destruction of critical habitat for the species; however, destructive activities are not necessarily limited to those listed.

8. Measuring progress

The performance indicators presented below provide a way to measure progress toward achieving the population and distribution objectives. Every ten years, success of recovery strategy implementation will be measured against the following performance indicators:

• the extent of occurrence is at least 9,457 km² for Jefferson Salamander, and at least 24,624 km² for dependent Unisexuals
• the number of extant breeding sites totals at least 28 for Jefferson Salamander and 53 for dependent Unisexuals
• the index of area of occupancy is at 188 km² or more for Jefferson Salamander, and 728 km² or more for dependent Unisexuals

9. Statement on action plans

One or more action plans will be completed for Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population by December 31, 2028.

10. Effects on the environment and other species

A strategic environmental assessment (SEA) is conducted on all SARA recovery planning documents, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals^{Footnote 34}. The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally sound decision-making and to evaluate whether the outcomes of a recovery planning document could affect any component of the environment or any of the Federal Sustainable Development Strategy’s^{Footnote 35} (FSDS) goals and targets.

Recovery planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that strategies may also inadvertently lead to environmental effects beyond the intended benefits. The planning process based on national guidelines directly incorporates consideration of all environmental effects, with a particular focus on possible impacts upon non-target species or habitats. The results of the SEA are incorporated directly into the strategy itself, but are also summarized below in this statement.

Recovery efforts that are focused on the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population will likely benefit species inhabiting extant breeding sites and the surrounding habitat, including Blue-spotted Salamander (Ambystoma laterale). No species of conservation concern are expected to be detrimentally affected from recovery activities for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population.

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Appendix A: Critical habitat maps

Figure A. Overview of critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada.

Figure A-1. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-2. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-3. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-4. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-5. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-6. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-7. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-8. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-9. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-10. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-11. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-12. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-13. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-14. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-15. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-16. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-17. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-18. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-19. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-20. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-21. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-22. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Figure A-23. Detailed critical habitat for the Jefferson Salamander and Unisexual Ambystoma, Jefferson Salamander dependent population in Canada. The area within which critical habitat is found for the Jefferson Salamander and the Unisexual Ambystoma, Jefferson Salamander dependent population in Canada, as described in section 7.1, is represented by the yellow shaded unit. Within this area, critical habitat only occurs where the biophysical attributes described in section 7.1.2 are found. The 1 km × 1 km UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Appendix B: NatureServe subnational conservation ranks (S-Ranks) for Ambystoma jeffersonianum and Ambystoma x 1 in Canada and the United States

Rank definitions

S1 – Critically Imperiled:

At very high risk of extirpation in the jurisdiction due to very restricted range, very few populations or occurrences, very steep declines, severe threats, or other factors.

S2 – Imperiled:

At high risk of extirpation in the jurisdiction due to restricted range, few populations or occurrences, steep declines, severe threats, or other factors.

S3 – Vulnerable:

At moderate risk of extirpation in the jurisdiction due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats or other factors.

S4 – Apparently Secure:

At a fairly low risk of extirpation in the jurisdiction due to an extensive range and/or many populations or occurrences but with possible cause for some concern as a result of local recent declines, threats or other factors.

S5 – Secure:

At very low or no risk of extirpation in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats.

SNA – Not Applicable:

A conservation status rank is not applicable because the species is not a suitable target for conservation activities.

SNR – Unranked

National or subnational conservation status not yet assessed.

SU:

Unrankable – Currently unrankable due to lack of information or due to substantially conflicting information about status or trends.

Part 2 – Recovery strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) in Ontario, prepared by J. Linton, J. McCarter and H. Fotherby for the Ontario Ministry of Natural Resources and Forestry, 2018

Jefferson Salamander (Ambystoma jeffersonianum) and Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) in Ontario

Ontario Recovery Strategy Series

2018

Natural. Valued. Protected.

Ministry of Natural Resources and Forestry

About the Ontario recovery strategy series

This series presents the collection of recovery strategies that are prepared or adopted as advice to the Province of Ontario on the recommended approach to recover species at risk. The Province ensures the preparation of recovery strategies to meet its commitments to recover species at risk under the Endangered Species Act (ESA) and the Accord for the Protection of Species at Risk in Canada.

What is recovery?

Recovery of species at risk is the process by which the decline of an endangered, threatened, or extirpated species is arrested or reversed, and threats are removed or reduced to improve the likelihood of a species' persistence in the wild.

What is a recovery strategy?

Under the ESA a recovery strategy provides the best available scientific knowledge on what is required to achieve recovery of a species. A recovery strategy outlines the habitat needs and the threats to the survival and recovery of the species. It also makes recommendations on the objectives for protection and recovery, the approaches to achieve those objectives, and the area that should be considered in the development of a habitat regulation. Sections 11 to 15 of the ESA outline the required content and timelines for developing recovery strategies published in this series.

Recovery strategies are required to be prepared for endangered and threatened species within one or two years respectively of the species being added to the Species at Risk in Ontario list.  Recovery strategies are required to be prepared for extirpated species only if reintroduction is considered feasible.

What's next?

Nine months after the completion of a recovery strategy a government response statement will be published which summarizes the actions that the Government of Ontario intends to take in response to the strategy. The implementation of recovery strategies depends on the continued cooperation and actions of government agencies, individuals, communities, land users, and conservationists.

For more information

To learn more about species at risk recovery in Ontario, please visit the Ministry of Natural Resources and Forestry Species at Risk webpage.

Recommended citation

Linton, J, J. McCarter and H. Fotherby 2018. Recovery Strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) in Ontario. Ontario Recovery Strategy Series. Prepared for the Ontario Ministry of Natural Resources and Forestry, Peterborough, Ontario. vii + 58 pp.

Cover illustration: Jefferson Salamander (top) photo by Jennifer McCarter. Unisexual Ambystoma (Jefferson Salamander dependent population) (bottom) photo by Joe Crowley.

Content (excluding the cover illustration) may be used without permission, with appropriate credit to the source.

Cette publication hautement spécialisée «Recovery strategies prepared under the Endangered Species Act, 2007», n’est disponible qu’en anglais en vertu du Règlement 411/97 qui en exempte l’application de la Loi sur les services en français. Pour obtenir de l’aide en français, veuillez communiquer avec recovery.planning@ontario.ca.

Authors

Jessica Linton, Natural Resource Solutions Inc.

Jennifer McCarter, Natural Resource Solutions Inc.

Heather Fotherby, Natural Resource Solutions Inc.

Acknowledgments

This document represents an update to a recovery strategy which was prepared by the Jefferson Salamander Recovery and Implementation Team (formerly called the Recovery Team) in 2010. The authors would like to acknowledge the extensive work that went into that strategy, which forms the basis of this document. In developing the original strategy the members of the Recovery and Implementation Team wished to acknowledge people who have submitted salamander eggs to the University of Guelph for identification, in particular Mary Gartshore, Bill Lamond, Al Sandilands and Craig Campbell. They also thanked David Servage, Lesley Lowcock and Alison Taylor, who made significant contributions to our understanding of the complex Ambystoma laterale (Blue-Spotted Salamander)–jeffersonianum complex during their tenures in the Master of Science program at the University of Guelph. Karine Bériault and Cadhla Ramsden’s research on habitat requirements and non-lethal sampling methods was invaluable. Leslie Rye and Wayne Weller were acknowledged for accumulating the information and producing a status report on Jefferson Salamander for the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Special mention was also extended to Brenda Van Ryswyk, John Pisapio and Albert Garofalo, who collected much of the data for radio-telemetry studies noted in this report, and to Pete Lyons, who provided property access. The Recovery and Implementation Team also thanked Fiona Reid and Don Scallen for their help with locating new populations of this species.

The authors of the recovery strategy for the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) would like to thank the Recovery and Implementation Team for their assistance with developing a comprehensive strategy. Dr. James Bogart at the University of Guelph provided guidance to the authors throughout the development of this strategy and is acknowledged for reviewing and providing feedback on various drafts. The following individuals are thanked for providing specific input based on their experiences in relevant jurisdictions: Sue Hayes, Heather Lynn, Anne Marie Laurence, Graham Buck, Mark Heaton, Joshua Shea, and Joe Crowley.

Declaration

The recovery strategy for the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) was developed in accordance with the requirements of the Endangered Species Act, 2007 (ESA). This recovery strategy has been prepared as advice to the Government of Ontario, other responsible jurisdictions and the many different constituencies that may be involved in recovering the species.

The recovery strategy does not necessarily represent the views of all of the individuals who provided advice or contributed to its preparation, or the official positions of the organizations with which the individuals are associated.

The goals, objectives and recovery approaches identified in the strategy are based on the best available knowledge and are subject to revision as new information becomes available. Implementation of this strategy is subject to appropriations, priorities and budgetary constraints of the participating jurisdictions and organizations.

Success in the recovery of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this strategy.

Responsible jurisdictions

Ontario Ministry of Natural Resources and Forestry

Environment and Climate Change Canada – Canadian Wildlife Service, Ontario

Executive summary

The Jefferson Salamander (Ambystoma jeffersonianum) is a relatively large, uniformly grey to brownish-grey salamander with variable amounts of grey-blue speckling along the sides of the body and the long, laterally compressed tail. The snout, limbs and toes on the hind feet are relatively long compared to other Ambystoma species. The Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale - (2) jeffersonianum) is morphologically similar to the Jefferson Salamander. Both salamanders occur sympatrically across Ontario and are only differentiated from each other through the genetic analysis of their genomotype. They generally occur in the eastern portion of the Carolinian zone and along the Niagara Escarpment in Ontario. Throughout this range, there are several geographically isolated subpopulations.

Recent estimates, based on long-term data sets for Jefferson Salamander, suggest a decline of more than 90 percent over the last three generations (33 years) of this species in Ontario. The Unisexual Ambystoma (Jefferson Salamander dependent population) have a unique reproductive strategy (kleptogenesis) where sperm from a male Jefferson Salamander is needed to initiate egg development. Their population is, therefore, dependent on the presence of Jefferson Salamander for their survival. A decline in the Jefferson Salamander would also result in a decline of unisexual Ambystoma Jefferson Salamander dependent population. The Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) were listed on the Species at Risk in Ontario (SARO) List as endangered in 2011 and 2017, respectively, affording each of them species and habitat protection under the Endangered Species Act (ESA, 2007).

The survival and recovery of the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) is primarily threatened by habitat loss, degradation, and fragmentation of woodlands and breeding ponds. The vast majority of suitable habitat within the known range of these two species has been cleared, initially for agriculture and subsequently for urban development. Other major threats include road-related threats (for example, vehicles and pollutants) and changes in pond hydrology. They are threatened to a lesser extent by forestry activities, recreational land uses, unauthorized collection, invasive and introduced species, and agricultural land uses.

The recommended recovery goal is to ensure that existing threats to populations and habitat of the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) are sufficiently removed to allow populations to become stable or increase in abundance and distribution throughout Ontario. The protection and recovery objectives are to:

1. identify and monitor extant populations of the Jefferson Salamander and unisexual Ambystoma Jefferson Salamander dependent populations in Ontario
2. continue to research the species’ movements and habitat use to inform habitat protection and restoration
3. identify historic and presently unoccupied areas with the potential for enhancement, restoration (that is, recovery habitat) and eventual recolonization or reintroduction of the species
4. assess and quantify threats to Jefferson Salamander and unisexual Ambystoma Jefferson Salamander dependent populations
5. develop, test and implement threat mitigation techniques in order to reduce threats affecting Jefferson Salamander and unisexual Ambystoma Jefferson Salamander dependent populations
6. develop a communication strategy to inform municipalities, planners, the development industry, property managers and other stakeholders of the habitat mapping and protection requirements for the Jefferson Salamander and Jefferson dependent unisexuals under the ESA 2007 and actively engage these stakeholders in effective habitat creation and restoration techniques and other recovery planning initiatives

The short-term recovery approaches should focus on the protection of existing populations of the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) by minimizing further loss or degradation of known habitat or potential recovery habitat. Recovery approaches should also focus on verifying, documenting, and monitoring the distribution and habitats used by extant, historic, and potential subpopulations. Developing and evaluating mitigation and restoration techniques, actively conducting research, and developing long-term management activities should also be prioritized to ensure the recommended recovery goal will be achieved.

On February 18, 2010, a habitat regulation came into force under the ESA 2007 for the Jefferson Salamander (O. Reg. 242/08). Although the Unisexual Ambystoma (Jefferson Salamander dependent population) was not protected under the ESA at the time, the species was used as a surrogate to indicate the presence of Jefferson Salamander, since their existence is dependent on the presence of male Jefferson Salamanders. Therefore, in cases where unisexual Ambystoma Jefferson Salamander dependent populations were found, the ESA applied. Generally, the regulation includes breeding ponds for both salamanders, the 300 m area adjacent to breeding ponds which provides suitable foraging, dispersal, migration or hibernation conditions, potential breeding ponds to which juveniles could disperse to within 1 km of a known breeding pond, and suitable terrestrial dispersal habitat between these areas.

The current regulation is effective at protecting both Jefferson Salamander and the Unisexual Ambystoma (Jefferson Salamander dependent population), however some amendments should be considered. Recommended amendments include adding Unisexual Ambystoma (Jefferson Salamander dependent population) as a distinct taxon and adding additional areas (the Municipality of Chatham-Kent, Durham Region, and Oxford and Perth Counties) in which the regulation applies.

1.0 Background information

Jefferson Salamander (Ambystoma jeffersonianum) was first described by Green in 1827 (Uzzell and Goldblat 1967). Considerable confusion about the species’ taxonomy has followed because of the sympatric occurrence of polyploid, all-female unisexual populations of Ambystoma salamanders that use sperm from male Jefferson Salamanders in reproduction (COSSARO 2016). The taxonomic and nomenclature histories of the Jefferson Salamander and sympatric unisexual salamanders include taxonomic groups now considered distinct species or synonyms (Matson 2013). The debate surrounding the taxonomic status of the Unisexual Ambystoma (Jefferson Salamander dependent population) is summarized in detail in COSEWIC 2016. Briefly, they do not correspond to any species concept other than comprising a monophyletic mitochondrial lineage which makes them genetically distinct.

Populations of unisexuals which occur sympatrically with Jefferson Salamander are referred to as Jefferson dependent unisexuals (Ambystoma laterale - (2) jeffersonianum) throughout this report for simplicity. Populations of unisexual Ambystoma also occur in Canada in association with other bisexual species whose males serve as sperm donors. This includes a unisexual Ambystoma Small-mouthed Salamander dependent population (Ambystoma laterale - texanum) and a unisexual Ambystoma Blue-spotted Salamander dependent population (Ambystoma (2) laterale - jeffersonianum). The morphology and distribution of unisexual Ambystoma populations is determined by their associated sperm-donating species.

1.1 Species assessment and classification

1.2 Species description and biology

Species description

The Jefferson Salamander is a relatively large (60-130 mm total length or 65–95 mm snout-to-vent length), uniformly grey to brownish-grey salamander with variable amounts of grey-blue speckling along the sides of the body and the long, laterally compressed tail (Figure 1) (Petranka 1998, Mills 2016). The snout, limbs and toes on the hind feet are relatively long compared to other species of Ambystoma (Mills 2016).

Jefferson dependent unisexual salamanders (Figure 2) are morphologically similar to the Jefferson Salamander; however, because they have chromosome sets from two or more species, the number and species origin of those chromosome sets dictates their morphology. All Jefferson dependent unisexuals possess at least one set of Blue-spotted Salamander (Ambystoma laterale) chromosomes which typically gives them more grey-blue-flecks or spots along the sides than Jefferson Salamanders (COSEWIC 2016).

Despite slight variations in appearance, Jefferson Salamanders and unisexuals dominated by either Jefferson or Blue-spotted Salamander genomes cannot be reliably distinguished from appearance alone; genetic analysis is required. The larvae and juveniles of both the Jefferson Salamander and Jefferson dependent unisexuals are also morphologically indistinguishable. After hatching, larvae are olive green to brown with yellow mottles on the sides. They are 8-10 mm in total length with four legs (unlike frog or toad larvae), a tall tail fin and feathery external gills behind a relatively broad head (Figure 3) (Petranka 1998, Mills 2016). Recently metamorphed individuals are 45-75 mm in total length (Petranka 1998, Matson 2013) and look like miniature adults. They are uniformly greenish or grayish-brown in colour with a dark dorsal line (Fotherby, pers. obs. 2017) and some speckling on the sides (Figure 4).

Figure 1. Adult Jefferson Salamander (Photo: Jennifer McCarter)

Figure 2. Adult unisexual Ambystoma Jefferson dependent population (Photo: Jessica Linton)

Figure 3. Young salamander larva (Photo: Jessica Linton)

Figure 4. Mature larva prior to transformation (Photo: Jessica Linton)

Figure 5. Recently metamorphed salamander (Photo: Jessica Linton)

Species biology

Jefferson Salamanders and Jefferson dependent unisexuals, like all species in the family Ambystomatidae, spend most of their lives underground (Petranka 1998, COSEWIC 2010, 2016). Their underground behaviours are not well documented, but they are thought to be ‘sit and wait’ predators, preying on earthworms and other invertebrates (Petranka 1998). Jefferson dependent unisexuals appear to exhibit the same behaviours as female Jefferson Salamanders throughout their life cycle (COSEWIC 2016). Both species are long-lived, having extremely high adult survivorship (Weller 1980) and potentially live at least 30 years (COSEWIC 2016).

Life cycle and reproduction

Jefferson Salamander and Jefferson dependent unisexuals are the earliest breeding Ambystoma species in Ontario. They typically migrate to breeding ponds during the first rainy nights of the spring when temperatures are above freezing, often before breeding ponds have completely thawed (COSEWIC 2016).

Breeding commences when groups of adults gather in scattered locations in a breeding pond. Male Jefferson Salamanders approach and court female salamanders, and deposit their spermatophores on pond substrates for females to pick up in their cloacae (Petranka 1998). Male Jefferson Salamanders are able to chemically distinguish between bisexual and unisexual females (Dawley and Dawley 1986) and are more likely to court and produce spermatophores for bisexual females (Uzzell and Goldblatt 1967, Uzzell 1969). Unisexual males have been documented in nature, although they are very rare. Bogart and Klemens (2008) looked at the genome composition of 1377 salamanders from 118 sites in Connecticut, Massachusetts, New Jersey, New York, Pennsylvania, and Virginia and found that the frequency of unisexual males was only 1.32 percent. Bogart (2003) suggests that such individuals are probably sterile and it is unknown if they could stimulate gynogenetic development of unisexual eggs.

One to two days after mating, females deposit small egg masses on emergent vegetation, twigs, or tree branches that have fallen into the water (Petranka 1998). Each egg mass is made up of 16 to 40 large (2.0 to 2.5 mm) eggs, which contain a black or dark brown embryo enclosed in a distinct envelope. A loose, watery layer of protective gel surrounds the eggs (Bishop 1947) (Figure 6).

Figure 6. Jefferson Salamander egg mass (Photo: Jessica Linton)

The dark melanin pigment, gel, symbiotic algae in the gel, and the dissolved organic matter in the water protect the developing embryos from damaging ultraviolet B radiation (Licht 2003). Individual females lay several egg masses, which altogether may contain more than 200 eggs, depending on the size of the female. Jefferson Salamander egg masses have lower egg mortality than Jefferson dependent unisexual egg masses. Hatching success of Jefferson Salamander eggs has been reported to be between 60 and 88 percent (Cook 1983) compared to 20 to 39 percent for Jefferson dependent unisexuals (Wilbur 1971, Bogart and Licht 1986, Bogart et al. 1987, Bogart et al. 2009).

Survival rates of larvae prior to metamorphosis are believed to be very low at 0 to 0.7 percent (Thompson et al. 1980, Mullen and Klueh 2009, Matson 2013). In Ontario, larval survival rates have been observed to be low in most breeding ponds, especially for the Jefferson dependent unisexuals, which is thought to have genetic viability issues (Bogart and Licht 1987). In addition, survival and recruitment can be highly variable year to year and can be negatively affected by ponds drying prior to larval transformation (COSEWIC 2010).

Jefferson Salamander larvae exhibit a slightly shorter larval period than Jefferson dependent unisexuals; their larval period is 94.6 days on average compared to an average of 95.8 days for unisexual larvae (Wilbur 1971). This may provide a competitive advantage to Jefferson Salamander larvae as breeding ponds begin to dry up and food supplies become depleted throughout the summer (Wilbur 1971).

Breeding success varies from year to year, depending on spring weather and water-level conditions. However, because they are long-lived, populations under normal conditions can be resilient to such variable reproductive output. Larvae hatch after two to four weeks (depending primarily on water temperature) and then spend another two to four months foraging in the pond (Petranka 1998). Jefferson Salamander larvae are known to cannibalize other salamander larvae, including conspecifics (Matson 2013). The larval stage varies in duration and can extend into early September. In Ontario, metamorphosis from the aquatic to terrestrial body form normally occurs in July and August. After transformation the salamanders move out of the pond and seek shelter in the forest litter.

Male Jefferson Salamanders in Ontario have been estimated to return to their natal ponds to breed approximately 22 months after metamorphosis (Weller 1980). Female Jefferson Salamanders and Jefferson dependent unisexuals, on the other hand, are estimated to reach sexual maturity after 34 months (Weller 1980). Jefferson dependent unisexuals breed more frequently than bisexual salamanders; Jefferson Salamanders, especially females, do not breed every year (Weller 1980).

There are no studies that examine age-specific survivorship of Jefferson Salamander, but Jefferson dependent unisexuals are thought to live longer than bisexual salamanders (COSEWIC 2010). Based on mark-recapture data, Matson (2013) found that males live for at least 9 years, bisexual females can live for more than 10 years, and Jefferson dependent unisexuals can live for more than 11 years. However, a study examining skeletochronology of another Ambystoma species, Spotted Salamanders (Ambystoma maculatum), suggests that they may live up to 32 years (Flageole and Leclair 1992). In addition, a Jefferson dependent unisexual individual first observed breeding in 1988 was still alive in 2015 meaning that it would be at least 30 years old (COSEWIC 2016).

Dispersal

Both Jefferson Salamander and Jefferson dependent unisexuals occupy terrestrial and aquatic habitats and may play an important role in channeling nutrients between the aquatic and upland wooded environments (Capps et al. 2014, Davic and Welsh 2004). Terrestrial habitat use and emigration by Jefferson Salamanders and Jefferson dependent unisexuals, especially metamorph dispersal and movements of juveniles, have not been well studied. Although radio-telemetry can provide accurate data on adult salamander movements, it has several limitations such as limited battery life and the requirement of invasive surgical procedures. In addition, the size of the transmitters only allows for implantation in adults and, therefore, no radio-telemetry studies have been conducted on juvenile salamander movements.

Weller (1980) marked metamorph Jefferson Salamanders and sympatric unisexuals using digit amputation in the Region of Peel in the late 1970s. Until recently, this was the only known mark-recapture study conducted in Ontario on dispersal of Jefferson Salamander metamorphs. Williams (1973) tracked metamorph Jefferson Salamanders using radioactive tags in Indiana and reported that individuals were found an average of 92 m from the breeding pond in 10 days, with a range of 3 to 247 m.

A multi-year metamorph and juvenile dispersal study initiated in 2015 employing pitfall trap capture-mark-recapture in the Hamilton area of Ontario has documented that the majority of metamorphs (n= 26) spent their first winter 6 to 14 m from the edge of their natal pond (Linton et al. 2016). Metamorphs travelled considerably less distance than reported in the literature (Williams 1973). It was theorized that, because the habitat is uniformly high quality around the study pond, metamorphs did not need to travel far to find suitable foraging and overwintering habitat (Williams 1973). To date, a strong correlation between time and travel distance has not been observed. Based on the distance between traps, one individual travelled 47 m in two days, while another took 10 days to travel 27 m.

Many subpopulations are separated from each other by more than one kilometre; given the maximum known movement distances, salamanders are unlikely to be able to disperse between them (COSEWIC 2016).

Intraspecific competition and/or predation

In a recent Ontario study, Jefferson Salamanders had a much higher larval transformation success rate than Jefferson dependent unisexuals despite there being a higher proportion of unisexual adults in the population (Linton et al. 2016). This suggests that, despite being in the minority of salamanders breeding in the study pond, Jefferson Salamanders were the most successful at recruiting metamorphs (Linton et al. 2016). Explanations for this observation include: Jefferson Salamanders are known to have a higher proportion of viable eggs, a shorter larval period, cannibalistic larvae, and Jefferson Salamander males prefer to breed with bisexual females. Unisexuals, in turn, may make up a higher proportion of the adult population if they live longer or return more frequently to the pond to breed.

Jefferson Salamander larvae are voracious aquatic predators that feed on moving prey such as insect larvae, small crustaceans and amphibian larvae including other Ambystoma larvae. Adults and larvae are likely prey for wetland predators, such as snakes, rodents and birds (COSEWIC 2016). At one site where pond levels receded drastically due to drought, predation of larvae by Raccoon (Procyon lotor) and Wild Turkey (Meleagris gallopavo) was observed to increase as the pond levels decreased (Linton, pers. observation 2016).

Genetics

Contrary to earlier theories, there is no evidence of past or present hybridization between Jefferson and Blue-spotted Salamanders (Bogart 2003). Mitochondrial DNA from Ambystoma unisexual individuals pre-dates that of the Jefferson Salamander (and Blue-spotted Salamander) (Bogart et al. 2007) and aligns most closely with that of a Kentucky population of the Streamside Salamander (Ambystoma barbouri) (Bogart 2003). Jefferson dependent unisexuals all share a very similar mitochondrial DNA, which arose 3 to 5 million years ago, that is distinctly different from any bisexual species, making them the oldest lineage of unisexual vertebrates known (Bi and Bogart 2010).

The nuclear genome of unisexual Ambystoma individuals is unrelated to their mitochondrial genome and is generally polyploid. Polyploid genomes contain three or more complete sets of chromosomes and Jefferson dependent unisexuals are usually triploid, however, diploid, tetraploid and pentaploid individuals have also been documented (Bogart 2003). An increase in ploidy levels in unisexual Ambystoma is a result of the incorporation of nuclear genomes from sympatric populations of bisexual species. The nuclear genome of Jefferson dependent unisexuals is predominated by chromosomes that have been incorporated from Jefferson Salamander. This is in contrast, for example, to unisexual Ambystoma Blue-spotted Salamander dependent population where chromosomes are predominated by Blue-spotted Salamander chromosomes.

The genetic mixing that occurs between unisexual Ambystoma and bisexual populations is attributed to an unusual reproductive strategy referred to as kleptogenesis (Bogart et al. 2007). Under this reproductive strategy, unisexual females lay unreduced eggs or eggs whose number of sets of chromosomes is equivalent to that of the parent’s somatic cells. Sperm from a diploid male is required to initiate development of the eggs and the male’s genome is normally not incorporated (Elinson et al. 1992). In some cases, however, the male’s genome is incorporated into the genome of the embryos (Bogart 2003). This incorporation can result in ploidy elevation (from triploid to tetraploid) or genome replacement if the male’s genome is incorporated in an egg that has possibly undergone a meiotic reduction. Ploidy elevation has been documented to occur in several populations and can be induced experimentally (Bogart et al. 1989). A possible advantage to this reproductive strategy is the incorporation of genes that are highly adapted to a particular environment as well as the ability to eliminate genomes that have deleterious alleles (Bogart et al. 2007).

All-female populations of Jefferson dependent unisexuals coexist with Jefferson Salamander populations owing to their reliance on the presence of a male Jefferson Salamander sperm donor for reproduction. In the absence of a bisexual Jefferson Salamander sperm donor, they do not appear to be able to reproduce parthenogenetically or use the sperm of other co-occurring species of Ambystoma such as Spotted Salamanders (Bogart et al. 2017). Therefore, both the Jefferson Salamander and the Jefferson dependent unisexuals are limited by their dependence on male Jefferson Salamander sperm donors for reproduction (Bogart and Licht 1987, COSEWIC 2016). Jefferson dependent unisexuals have been found in ponds without a sperm donor, although it is presumed that a sperm donor was present at one time (Bogart et al. 2017). In this regard, the presence of eggs of Jefferson dependent unisexuals necessarily and absolutely indicates the presence of a breeding bisexual Jefferson Salamander at some point in time (Rye and Weller 2000, Bogart and Klemens 1997, 2008, COSEWIC 2016).

Species and ploidy identification

At the University of Guelph, microsatellite molecular markers for the Jefferson Salamander (Julian et al. 2003) have been, and continue to be, used effectively to identify and distinguish Jefferson Salamanders from Jefferson dependent unisexuals. These markers may also help address other questions regarding population dynamics and genetics that involve the unisexual members of the complex.

With support from the Species at Risk Research Fund for Ontario, an Environmental DNA (eDNA) survey protocol was developed and tested (MNRF 2015). This method could be used to rapidly detect genetic material shed by Jefferson Salamanders into the environment and could be used to better understand the distribution and occurrence of that species across its range. The Biodiversity Institute of Ontario at the University of Guelph is currently conducting a study to assess the detection probability of eDNA for the Jefferson Salamander, quantify the distribution of eDNA across space and time in multiple vernal pools, and to determine if this type of detection is a viable means to monitor this species (S. Crooks pers. comm. 2017). Initial results have been promising for detection of Jefferson Salamander and unisexuals. Since the eDNA method currently targets mitochondrial DNA, which is virtually the same in all unisexual Ambystoma, it cannot distinguish between Jefferson dependent and Blue-spotted dependent unisexuals (J. Bogart pers. comm. 2018). Once unisexuals, which are the most common members of the complex in most ponds in southern Ontario, are confirmed in a pond through eDNA methods, more intensive sampling can be done to determine whether the sperm donor is a Jefferson Salamander (J. Bogart pers. comm. 2018).

1.3 Distribution, abundance and population trends

Global range

The global distribution of the Jefferson Salamander is restricted to eastern North America, extending from Illinois in the west, which has isolated populations in only two eastern counties (Petranka 1998), across Indiana, Kentucky and West Virginia to Virginia in the east and northeast to Vermont and New Hampshire. The Canadian range of the Jefferson Salamander is only known to occur in southern Ontario and represents the species’ northern range limit (Figure 7).

Throughout northeastern North America, unisexual Ambystoma are found in association with their sperm-donating bisexual salamander species [Small-mouthed Salamander (Ambystoma texanum), Blue-spotted Salamander or Jefferson Salamander]. Unisexual Ambystoma do not extend to the northern limit of the Blue-spotted Salamander, however. Their northern limit only extends to north-central Ontario, southern Quebec, and Minnesota (COSEWIC 2016).

Jefferson dependent unisexuals are found in association with Jefferson Salamander populations throughout the Jefferson Salamander range. Genetic data describing the salamanders’ genomotypes are unavailable for much of the range, so the precise distribution of Jefferson Salamander compared to Jefferson dependent unisexuals is not known (Bogart and Klemens 1997). Jefferson dependent unisexuals have, however, been confirmed in 10 of the 14 states where the Jefferson Salamander occurs (Connecticut, Indiana, Kentucky, Massachusetts, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, and Vermont) (Bogart and Klemens 2008, Bogart pers. data 2017). Jefferson dependent unisexuals have also been confirmed in southeastern Michigan, although Jefferson Salamander has not yet been documented in the state (Bogart pers. data 2017). The presence of the Jefferson dependent unisexuals in southeastern Michigan indicates that Jefferson Salamander likely were, or are still, present in the area.

Figure 7. Global Range of Jefferson Salamander and/or unisexual Ambytoma Jefferson dependent population

(Map produced by Natural Resource Solutions Inc. based on NatureServe 2016 and Bogart pers. data 2017).

The current global conservation status rank for the Jefferson Salamander is G4 or ‘Apparently Secure’, a level of ranking assigned to species with greater than 100 site occurrences and greater than 10,000 individuals (NatureServe 2016). In the United States, the Jefferson Salamander is nationally listed as ‘Apparently Secure’ (N4) as of 2001, although it is designated as ‘Imperilled’ (S2) in Illinois, Vermont and West Virginia and is considered to be ‘Apparently Secure’ (S4) in 4 of the 14 states where it is found (Table 3). In Canada, the Jefferson Salamander was assessed as ‘Imperilled’ (N2) in 2011 (NatureServe 2016) and is listed as endangered on Schedule 1 of the federal Species at Risk Act (SARA 2002). Jefferson Salamander was assessed as ‘Imperilled’ (S2) in Ontario and is listed as endangered under the Ontario provincial ESA, 2007.

Jefferson dependent unisexuals currently have no global conservation status ranking (NatureServe 2016). Several jurisdictions have provided Jefferson dependent unisexuals legal protection along with the Jefferson Salamander. In Connecticut, the Jefferson Salamander “complex”, and in Massachusetts, the Jefferson dependent unisexuals are listed as Special Concern (Connecticut Department of Energy and Environmental Protection 2015, Massachusetts Division of Fisheries and Wildlife 2016). Jefferson dependent unisexuals were assessed by the Committee on the Status of Species at Risk in Ontario (COSSARO) in December 2016 as endangered (COSSARO 2016). This resulted in the species being added to the SARO List under the provincial ESA, 2007 in June 2017 and being ranked S2 in Ontario (NHIC 2017).

Table 3 legend:

N2/S2

Imperilled (that is, extremely rare or especially vulnerable)

S2S3

The status could range from Imperilled to Vulnerable

S3

Vulnerable to extirpation or extinction (that is, rare and uncommon)

S3S4

The status could range from Vulnerable to Apparently Secure

G4/N4/S4

Apparently Secure (that is, uncommon but not rare)

SNR/NNR/GNR

conservation status not yet assessed

Canadian range

In Canada, Jefferson Salamander and Jefferson dependent unisexuals, generally occur in the eastern portion of the Carolinian zone and along the Niagara Escarpment in Ontario. There are also geographically isolated populations dispersed throughout the range (Figure 8).

There are records of Jefferson Salamander in Brant County, the City of Hamilton, Dufferin, Elgin, Grey and Haldimand Counties, Halton and Niagara Regions, Norfolk County, Peel and Waterloo Regions, Wellington County, and York Region (Figure 8). There are records of Jefferson dependent unisexuals, as they occur in all known Ontario Jefferson Salamander populations, in all the areas listed above as well as in the Municipality of Chatham-Kent, Durham Region, and in Oxford and Perth Counties (Figure 8).

Percentage of the global distribution in Canada

Populations of the Jefferson Salamander and Jefferson dependent unisexuals in Canada are situated at the northern limit of the species’ North American range. The Canadian populations probably represent a maximum of one to three percent of the estimated North American population, based on relative ranges (Rye and Weller 2000) (Figure 8).

Figure 8. Historical and current distributions of the Jefferson Salamander and unisexual Ambystoma Jefferson dependent population in Ontario (based on the database of all Ontario locations that was compiled by the Recovery and Implementation Team and housed by Dr. James Bogart at the University of Guelph).

Population sizes and trends

The present knowledge of this species indicates that the current isolated sub-populations are remnants of what was once a more extensive, continuous range throughout southern Ontario. Fragmentation and loss of habitat have led to the isolation of these sub-populations. In southern Ontario, 63 percent of the original forests and over 85 percent of historic wetlands have been lost since European settlement (Butt et al. 2005, DUC 2010). Habitats have been further lost and fragmented as a result of large-scale agriculture, urbanization, road networks and resource development activities, such as aggregate extraction.

Long-term, detailed trend data are not available for Jefferson Salamander and Jefferson dependent unisexuals across the entire range in Ontario due to the difficulties differentiating these species without genetic data. Prior to 2004, the method for genetically confirming individuals required that they be sacrificed for analyses (Bogart 1982). This made it impossible to determine the absolute frequencies of bisexual and unisexual individuals in populations or to estimate trends over time (COSEWIC 2016).

Normally, estimations of the distribution of vertebrate species may be obtained from museum records and voucher specimens. Historical identifications of Jefferson Salamander and unisexual Ambystoma specimens are, however, not necessarily accurate because genetic analysis techniques were not available. Unfortunately, it is very difficult to retrieve DNA from museum specimens as they were preserved in formalin and stored in ethanol (J. Bogart pers. comm. 2017). Therefore, it is not likely possible to distinguish between individuals of the complex that are catalogued in major museum collections.

New methods for genetic testing (using microsatellite DNA loci) allow for many individuals to be genotyped in a relatively short period of time using only small tissue samples (Ramsden et al. 2006, Bogart et al. 2007). Population trends have still only been estimated for very few populations, however, using observed numbers of egg masses over time (COSEWIC 2016). To collect accurate population trend data would require intensive survey efforts over multiple years which present limitations in terms of logistics and resources. Trends in population density and inferences on presence/absence data can only be estimated through repeated annual surveys of the same ponds combined with surveying several ponds in the same year (COSEWIC 2016). To ensure the protection of the species, restrictions on sampling effort are also applied (for example, standard protocols typically only allow for the collection of up to 20 tissue samples in a given pond per year).

Recent estimates, based on the best available long-term data sets for Jefferson Salamander, suggest a decline of more than 90 percent over the last three generations (33 years) (COSEWIC 2016). Repeat surveys over a 15-year timeframe (1990 to 2005) revealed that most subpopulations were declining and some were extirpated (COSSARO 2016). For example, surveys of 18 historically known breeding sites along the Niagara Escarpment that were documented in 1990 to 1991 revealed only three that were confirmed to still be supporting salamander populations in 2003 to 2004 (COSEWIC 2010). Overall, from 1990 to 2005, no subpopulation of Jefferson Salamanders in Ontario was estimated to be larger than when originally found (COSSARO 2011).

Based on the database that was compiled by the Recovery and Implementation Team (Figure 8) and the definition of a site as one or more breeding pond within 1 km of each other (COSEWIC 2016), a total of 40 sites in Ontario have been confirmed where Jefferson Salamander is known to occur. Twenty-eight of these sites have Jefferson Salamander observations from within the last 20 years (1997 to present), while the remaining 12 sites have no recent occurrences (that is, no documented observations since 1997). Jefferson dependent unisexuals have been confirmed in Ontario at a total of 83 sites, which includes sites where Jefferson Salamander are also known to occur. Fifty-three of these sites have observations of Jefferson dependent unisexuals from within the last 20 years (1997 to present), while the other 30 sites have no recent documented occurrences.

It is difficult to determine whether or not these species still occur at sites with historic records from greater than 20 years ago. Breeding habitat can be dynamic with conditions varying from year to year, depending on precipitation and water levels. This affects levels of breeding activity and success. Due to this variability, a minimum of three consecutive years of surveys are required at historic sites to determine the species’ absence with any degree of confidence. Such monitoring effort is rare. Although data is limited, it is anticipated that some of these populations are extirpated because of habitat changes associated with anthropogenic disturbance. For example, some historically-used breeding ponds have been stocked with predatory fish, some no longer hold water for the required time for larval development, and some have been lost to development (COSEWIC 2010).

Only a few studies have genetically identified large numbers of individuals in a given subpopulation to estimate comparative abundance of bisexual and unisexual individuals (see Table 4). In six studies that involved sample sizes larger than 100 individuals, the percentage of Jefferson dependent unisexuals ranged from approximately 60 to 92 percent of sampled individuals (Table 4).

Note: Frequencies are provided in numbers of individuals of each genomotype. All unisexual genomotypes have at least one A. laterale (L) chromosome complement and one or more A. jeffersonianum (J) complement or genomes. Diploids have 2, triploids have 3, and tetraploids have 4 chromosome complements.

1.4 Habitat needs

Jefferson Salamanders inhabit deciduous or mixed upland forests containing, or in close proximity to, suitable ponds for breeding (Klemens 1993). Jefferson Salamanders show fidelity to both their terrestrial and breeding habitats (Thompson et al. 1980, COSEWIC 2016, COSEWIC 2010, De Lisle and Grayson 2011). Jefferson dependent unisexuals use similar macro- and micro-habitats as bisexual Jefferson Salamanders (Bériault 2005, COSEWIC 2016, Hoffman 2017).

Terrestrial habitat

Following metamorphosis, Jefferson Salamanders and Jefferson dependent unisexuals are primarily terrestrial, using mature upland deciduous or mixed forest habitats for foraging, summer and fall movements, overwintering, and migration to and from breeding ponds (COSEWIC 2010). In general, these habitats are well-shaded, have a thick layer of leaf litter, high soil moisture, and lower substrate temperatures than random sites (Faccio 2003, Hoffman 2017). The amount of sub-canopy vegetation may or may not be an important factor for these salamanders. In Vermont, their forest habitats were characterized by a dense low shrub layer (Faccio 2003), whereas sites in Maine had lower levels of sub-canopy vegetation cover (<1 m tall) than random sites (Hoffman 2017). Various refugia are used during the active season including the underside of rocks, woody material and bark, beneath leaf litter, inside rotten logs, in rock fissures and between large rocks (Bériault 2005). The most commonly used active season refugia are small mammal burrows (Bériault 2005) which tend to be horizontal and highly branching (Faccio 2003).

Jefferson Salamanders and Jefferson dependent unisexuals may migrate through a variety of habitats during breeding migration movements including woodlands, plantations, agricultural fields, early successional areas, and across roads (COSEWIC 2010, 2016). Radio-telemetry studies have documented that post-breeding migratory movements of adults can range from hundreds of metres up to one kilometre from the breeding pond into surrounding habitat (Semlitsch 1998, Faccio 2003, Bériault 2005, COSEWIC 2016). While some individuals have been observed moving to locations outside forest habitats, under buildings, or near forest-lawn edges and roads, the vast majority of adults appear to stay within the forest habitat (Hoffman 2017). Radio-telemetry studies conducted in Ontario found that 90 percent of adults stay in the deciduous forest habitats within 300 m of their breeding pond (Bériault 2005, COSEWIC 2016).

Post-breeding observations of juveniles and adults are infrequent as they mostly remain secluded underground (Matson 2013). Very few studies have examined autumn movements of Ambystomatid salamanders. Two studies in Ontario investigated post-breeding terrestrial movements of Jefferson Salamander and/or Jefferson dependent unisexuals in Ontario through radio-telemetry (Beriault 2005, COSEWIC 2016). Neither of these studies, however, extended into the autumn to look at overwintering site selection and habitat use. For example, the Ontario Ministry of Natural Resources and Forestry (MNRF) Aurora District Office and Conservation Halton conducted radio-telemetry of post-breeding adult dispersal near Waterdown, Ontario but the radio transmitters’ batteries died by August so no insights into fall movements or specific overwintering habitats were gained (B. Van Ryswyk pers. comm. 2017).

Faccio (2003) used radio-telemetry to examine post-breeding terrestrial habitat use by Spotted Salamander (n=8) and Jefferson Salamander (n=8) between May and November in Vermont. Jefferson Salamanders moved an average of 122.6+ /- 44.4 m with a range of 11–405 m between their release point and their final overwintering site (Faccio 2003). This study concluded that overwintering occurs in deep, vertical small mammal burrows, and likely other small rock crevices or fissures, which extend below the frost line (Faccio 2003).

Breeding ponds

Mating, oviposition and larval development occurs in breeding ponds located in or near high quality forest habitats, including in limestone sinkhole ponds, kettle ponds and vernal pools (Nyman 1991) that have a sufficiently long hydro period (Matson 2013). These ponds are generally fed by groundwater, snowmelt or surface water, and dry in mid to late summer (COSEWIC 2010). Breeding ponds must be devoid of predatory fish and have sufficient egg mass attachment sites in the water, such as shrubs, twigs, fallen tree branches, submerged riparian vegetation or emergent vegetation (Thompson et al. 1980).

One study in Ontario found that breeding pond water depth, water temperature, pH, and other water-chemistry and water-quality parameters were not good predictors of the use of breeding ponds by Jefferson Salamander or Jefferson dependent unisexuals (Bériault 2005). Bériault acknowledged, however, that the sample size was small and that a narrow range of wetland types (wetlands that were confirmed breeding ponds or wetlands that looked suitable) were included in the study (2005). Jefferson Salamander larvae are not particularly susceptible to relatively low pH (COSEWIC 2010). Ample food to sustain the larvae must be present in breeding ponds. This includes small aquatic invertebrates and other amphibian larvae (COSEWIC 2010).

1.5 Limiting factors

Characteristics of Jefferson Salamander’s and Jefferson dependent unisexual’s life histories or ecology that may be limiting factors in their recovery include:

• intermittent juvenile recruitment
• limited dispersal ability
• terrestrial and breeding site fidelity
• requirement of the presence of male Jefferson Salamander sperm donors; and
• for Jefferson dependent unisexuals, competition with and/or predation by Jefferson Salamander during their larval stages

1.6 Threats to survival and recovery

The following threats to the Jefferson Salamander and Jefferson dependent unisexuals are presented in order of priority. This assessment is based on an analysis compiled by the Jefferson Salamander Recovery and Implementation Team with input from relevant land managers, a recent status assessment of Jefferson dependent unisexuals by COSSARO (2016) and an International Union for Conservation of Nature (IUCN) threats calculator to inform a COSEWIC status report on Jefferson dependent unisexuals (2016). It is inferred that threats to Jefferson Salamander and sympatrically occurring Jefferson dependent unisexuals are equal in terms of severity and scope.

High-impact threats to the survival and recovery of these salamander populations include habitat loss and degradation and fragmentation of woodlands and breeding ponds. This is attributed to a variety of activities and land uses described in more detail below. Most sub-populations are also exposed to high-medium road-related threats which include direct mortality, barriers to movement, and road-related pollutants (COSEWIC 2016). Additional low-impact threats include the introduction of carnivorous fish to breeding ponds, which can prey upon the egg, larval and adult stages of the species (MNRF 2015), agricultural land conversion, and free range livestock (COSEWIC 2016).

For consistency, the following discussion of threats is organized according to the IUCN-CMP (Conservation Measures Partnership) unified threats classification system (see Master et al. 2009 and CMP 2010 for details). Consistent with this approach, threats may be observed, inferred, or projected to occur in the near-term.

Habitat loss, fragmentation and degradation are considered the greatest threats to Jefferson Salamanders and Jefferson dependent unisexuals across their global range, including Ontario. Activities associated with urbanization, aggregate extraction and other resource development are the most significant threats to Jefferson Salamander and unisexual Ambystoma in southern Ontario.

Residential and commercial development (impact “high”)

The Carolinian forest reaches the northern limit of its distribution in southern Ontario, but the vast majority of this habitat in Ontario has been cleared, initially for agriculture and subsequently for urban development (COSSARO 2016). There is currently limited remaining habitat^{Footnote i} combined with a high development pressure of that habitat. Therefore, the most probable cause of low numbers of Jefferson Salamanders and Jefferson dependent unisexuals in Canada is the limited amount of suitable habitat, both breeding ponds and terrestrial foraging and migration habitat, and the continuing development pressures these habitats are experiencing.

Anthropogenic threats include development activities that result in the direct loss of habitat from a development footprint, cumulative loss and degradation of habitat, and fragmentation of breeding ponds and woodlands (see also Transportation and Service Corridors below). Habitat continues to be lost as a result of housing development, especially in areas experiencing rapid urban sprawl such as the Hamilton and Kitchener-Waterloo areas (COSEWIC 2016). Impacts from development include site clearing and grading that result in wetland filling, altered cover, topography and drainage patterns. Any alteration to the contributing drainage area of a wetland has the potential to negatively impact its hydrology and associated ecological function.

Development also increases impervious land cover, reduces groundwater recharge, and results in stormwater management which leads to sedimentation and altered natural hydroperiod regimes, water balance of adjacent wetlands (for example, shorter hydroperiods), and soil moisture content. Watercourse realignments through forests and swamps also have the potential to alter wetland hydrology and salamander breeding ponds specifically. During development, silt fencing can also prevent and/or hinder migration of salamanders if it is not properly positioned or timed.

Premature drying of ponds can result from the removal of a part of the protective canopy, drawing down the water table in developed areas, or altering watercourses for snowmelt and runoff. The reduction of vernal pond “envelopes” and buffer zones also has been suggested as contributing to the reduction and possible elimination of Ambystoma species (Calhoun and Klemens 2002).

Energy production and mining (impact “high”)

The Niagara Escarpment, which represents a substantial portion of the species’ range in Ontario, is a significant aggregate extraction area. When breeding ponds are filled or drained, local extirpations are inevitable. Any resource development activity that may alter the water table or cause a disruption or modification to groundwater flow has the potential to alter wetland hydroperiods and breeding habitat, water balance, wetland function and soil moisture regimes in adjacent salamander habitat. The presence of adequate water in the breeding ponds for the duration of the larval development period is critical to population recruitment.

Transportation and service corridors (impact “high – medium”)

Some roads (and urbanization) can create barriers that limit salamander dispersal and abundance. Southern Ontario has a dense network of roads and salamanders are frequently killed on roads by vehicles while migrating to or from a breeding pond (Beebee 2013). Road-kill is expected to have severe impacts on local populations of Jefferson Salamanders and Jefferson dependent unisexuals. Using data from 500 Spotted Salamander breeding ponds in Massachusetts, Gibbs and Shriver (2005) estimated an annual risk of road mortality of more than 10 percent can lead to local population extirpation. With a mortality risk of 20 to 30 percent, the entire population would be extirpated within 25 years (Gibbs and Shriver 2005). Road-kill is substantial in some areas in southern Ontario despite mitigation attempts (for example, road closures close to some breeding sites) (COSEWIC 2016).

Curbs can act as barriers to migratory movements and/or dispersal and catch basins can result in trapped individuals. Roads also are a source of chemicals and pollutants (for example, salt) that degrade adjacent aquatic and terrestrial habitat. Toxic effects of road salt application can extend considerable distances into wetlands and have been observed to have detrimental effects generally on amphibians and specifically on Spotted Salamanders (Turtle 2000, Karraker et al. 2008, Collins and Russell 2009). Roads also create zones of disturbance characterized by noise and light pollution, and may contribute to the desiccation of migrating adult salamanders or increase their vulnerability to predators.

Many woodlands in the province are traversed by utility easements (for example pipelines and hydro corridors), which require occasional maintenance work and often removal of vegetation. This work also has the potential to negatively impact the species and its habitat if appropriate mitigation measures (for example avoidance of sensitive timing windows, erosion and sediment control measures) are not implemented.

Agriculture and aquaculture (impact “low”)

Current rates of agricultural land conversion in southern Ontario are low; however where it occurs, the impacts to local populations can be severe if terrestrial salamander habitats are converted and/or breeding ponds are drained (COSEWIC 2016). Ongoing and new agricultural activities have the potential to cause further habitat loss and an increase in surface runoff, which could potentially have a negative impact on adjacent wetlands, including salamander breeding ponds. The installation of tile drains also has the potential to negatively impact wetlands and their adjacent areas.

Non-vegetated open areas such as agricultural fields may be used as migratory corridors between the breeding pond and forested areas. The extent to which agricultural practices (for example tilling) and chemical application impact individuals travelling through these habitats is not known.

Jefferson Salamanders and Jefferson dependent unisexuals are generally associated with deciduous woodlands making them vulnerable to forestry activities such as hazard tree removal and selective harvesting. Forestry activities and the equipment used may result in the filling of vernal pools, alteration of vernal pool hydrology, sedimentation, leaf litter and soil compaction removal or alteration of associated upland habitat (removal of canopy cover, stumps, logs and leaf litter, and alteration of nutrient inputs by leaves), pollution and fragmentation or isolation of vernal pools from the terrestrial habitat. The negative effects of forestry activities are not anticipated to be frequent but when they do occur, they could be severe.

Invasive and problematic species (impact “low”)

The potential impact of invasive species on Jefferson Salamander and Jefferson dependent unisexual populations is generally understudied. Although specific data are limited, introduced zooplankton is becoming an ecosystem-level problem in southern Ontario. Native arthropods are reluctant to feed on them and as a result, the salamander’s prey base could potentially be affected (COSEWIC 2016). Invasion by aquatic plants such as Common Reed (Phragmites australis), may also degrade breeding habitat, although specific data are unavailable.

Ambystomatid salamanders do not thrive with predatory fish, and many documented Jefferson Salamander breeding sites where the species no longer exists were noted to have been stocked with fish (COSEWIC 2016). Large predatory fish will prey on all life stages of the salamanders. Goldfish in Jefferson Salamander breeding ponds and associated potential impacts is an emerging concern, particularly for the Hamilton Conservation Authority (M. Stone, pers. comm. 2017).

Batrachochytrium salamandrivorans (Bsal) is a fungal pathogen that causes chytridiomycosis in salamanders and newts (Palahnuk and Buchanan 2015). It is thought to have originated in Asia and has recently been introduced to Western Europe where it is causing rapid population declines in European Fire Salamanders (Martel et al. 2014). A Chytrid Fungus Monitoring Project began in Ontario in 2013. To date, Bsal has not been reported in Ontario or anywhere else in North America (Palahnuk and Buchanan 2015). There are several other emerging amphibian pathogens such as Severe Perkinsea Infections (SPI) that are causing significant mortality in frogs (Isidoro-Ayza et al. 2017), however at this time there is no evidence to indicate it is a threat to salamander larvae.

In at least one known site, the presence of North American Beaver (Castor canadensis) has the potential to alter breeding pond hydrology (A. Featherstone pers. comm. 2017).

Climate change and severe weather (impact unknown)

The impacts that future climate change will have on Jefferson Salamanders and sympatrically occurring unisexuals is not known. Climate change predictions for southern Ontario include warmer temperatures, more winter precipitation, less summer precipitation (McDermid et al. 2015), and more extreme weather events such as droughts or flooding (IPCC 2014). Breeding occurs in ephemeral ponds; however adequate water must remain to support larval development through to transformation. Occasional early drying of vernal pools from prolonged droughts is likely normal and not detrimental to populations because adults have several breeding seasons and are long-lived (COSEWIC 2016). Multiple years of drought, however, especially consecutive years, would likely impact populations. The balance between winter snow accumulation, summer precipitation and water losses due to increased temperatures and evaporation will ultimately determine whether drought becomes an issue for salamander breeding.

Additional impacts to breeding ponds could occur due to more rapid snowmelt in the spring and intense rainfall events, which could increase runoff, erosion, sedimentation and decrease water retention, Mid-winter warm periods, which are more likely under current climate change scenario predictions (McDermid et al. 2015), can be problematic for the species, as well. In 2017, several jurisdictions reported early migrations to breeding ponds by Jefferson Salamander and Jefferson dependent unisexuals in late February. This warm period in 2017 was followed by a rapid drop in temperature and it is likely that many individuals, and potentially any egg masses laid, would have perished.

Biological resource use (impact unknown)

Collection of amphibians and reptiles for the pet trade is a growing concern and may be a threat to the Jefferson Salamander and unisexual Ambystoma. Specific location information is considered data sensitive and is not widespread in the general public.

Human intrusions and disturbance (impact unknown)

Heavy use by hikers, cyclists and all-terrain vehicle (ATV) users of recreational trails near breeding pools and in terrestrial habitats may result in salamander mortality or habitat degradation. ATVs sometimes damage breeding ponds, usually later in the summer, which may pose a threat to new metamorphs (COSEWIC 2016). At one site in Ontario, ATV-use has led to a substantial decline in high quality habitat (A. Featherstone pers. comm. 2017).

1.7 Knowledge gaps

Key knowledge gaps relating to the Jefferson Salamander and Jefferson dependent unisexuals include (but are not limited to) the following:

1. population abundance and proportion of Jefferson Salamander and Jefferson dependent unisexuals within subpopulations, as well as trends in these data over time
2. the effectiveness of mitigation efforts to address threats
3. the species’ current distribution and range, particularly in portions of the Oak Ridges Moraine Plan Area and the Greenbelt Plan Area
4. the impacts of agricultural practices on breeding ponds and migration
5. the species’ spatial ecology, including dispersal patterns, timing and distances; and
6. habitat use, particularly the location and characteristics of overwintering sites

1.8 Recovery actions completed or underway

The Jefferson Salamander has been protected from being killed, harmed, harassed, captured or taken since the ESA, 2007 came into force in 2008. Jefferson dependent unisexuals received equal protection when they were listed as endangered in 2017. Habitat protection for Jefferson Salamander has been in place since 2010 when the Ontario government completed a habitat regulation for the species. This habitat regulation, which was developed in response to the endangered status of the Jefferson Salamander, also protected habitat for sympatrically occurring Jefferson dependent unisexuals because they cannot persist without Jefferson Salamander being present.

Protecting the Jefferson Salamander and enforcing the regulation are key components in the implementation of the ESA 2007 and continue to be government-led actions, as identified in the Government Response Statement (MNRF 2015). Through the Species at Risk Stewardship Fund, the MNRF has supported more than 40 projects designed to contribute to the protection and recovery of the Jefferson Salamander (MNRF 2015).

Work on several of the original recommended recovery objectives identified for Jefferson Salamander in the 2010 Recovery strategy for the Jefferson Salamander (Ambystoma jeffersonianum) in Ontario has begun, and a number of studies on the species have been completed. A large proportion of this work informed the revision and development of updated recovery objectives for Jefferson Salamanders and Jefferson dependent unisexuals.

Identify and monitor extant populations of the Jefferson Salamander in Ontario

(Recovery Objective 1)

In 2002 and 2003, the Recovery and Implementation Team worked with the Regional Municipality of York to determine whether Jefferson Salamander and Jefferson dependent unisexual subpopulations existed in York Region. Field investigations revealed four subpopulations of Jefferson Salamander which are the only known occurrences in York Region and represent the easternmost occurrences in Ontario.

In 2003, the Recovery and Implementation Team formed a partnership with the University of Guelph to update the database of all known Jefferson Salamander and Jefferson dependent unisexuals occurrences. More than 100 wetlands with the potential to support Ambystoma species were searched to determine whether the Jefferson Salamander was present.

Also in 2003 and 2004, the Niagara Escarpment Biosphere Reserve, in partnership with Niagara Escarpment Commission’s Ontario’s Niagara Escarpment (ONE) Monitoring Program staff, and the University of Guelph, under the direction of the Recovery and Implementation Team, undertook a study to examine the location and habitat conditions of Jefferson Salamander breeding sites along the Niagara Escarpment. The study focused on historically known breeding locations that the University of Guelph had documented in 1990 and 1991.

In 2004, also under the direction of the Recovery and Implementation Team, a number of conservation authorities, including Grand River Conservation Authority, Hamilton Conservation Authority, Conservation Halton, Credit Valley Conservation, and Toronto and Region Conservation Authority, allocated staff time and resources to revisiting breeding sites previously known to support the Jefferson Salamander, and to investigating other potential habitats within their watersheds.

In 2006 and 2007, the University of Toronto Mississauga, Evergreen, EcoSource and Credit Valley Conservation, under the direction of the Recovery and Implementation Team, partnered to assess groundwater contributions and the potential impacts from recreational trails on a Jefferson Salamander breeding pond in Peel Region.

In 2013, the Recovery and Implementation Team updated a documented titled Sampling Protocol for Determining the Presence of Jefferson Salamanders (Ambystoma jeffersonianum) in Ontario. It is updated periodically to reflect the best scientific information available and feedback on the success of the methods it outlines. This document, which is equally applicable to Jefferson dependent unisexuals, includes information on salamander ecology, survey methods for determining presence/absence, recommendations on avoiding between-site contamination and permitting requirements to carry out survey work. This standardized data collection protocol has ensured consistent data collection since it was first produced in 2012.

The Niagara Peninsula Conservation Authority (NPCA) completed Jefferson Salamander surveys since 2013 at Woolverton, Cave Springs, and Wainfleet Bog Conservation Areas (K. Frohlich pers. comm. 2018). Jefferson Salamander and Jefferson dependent unisexuals were documented in 2013 and 2014 at Woolverton Conservation Area. Jefferson dependent unisexuals were documented at Cave Springs Conservation Area, where NPCA completed surveys for four years (2013, 2015-2017), with a fifth year planned for 2018. Although surveys were completed at Wainfleet Bog for three consecutive years (2013-2016), no Jefferson Salamander or Jefferson dependent unisexuals were documented.

The MNRF Guelph District Office has been surveying for Jefferson Salamanders at various sites since 2009 (G. Buck pers. comm. 2018). No Jefferson Salamander or Jefferson dependent unisexuals were captured in surveys at one site in Brant County (2009) or at one site off Maltby Road south of Guelph (2011). In 2011, the MNRF Guelph District Office also partnered with the Hamilton Conservation Authority (HCA) to conduct surveys in the Dundas Valley. Jefferson Salamander and Jefferson dependent unisexuals were confirmed and re-confirmed at six new and historic ponds throughout the area. HCA has since continued surveys in this area. In 2015, surveys were completed at two ponds in the Sudden Bog Area of Natural and Scientific Interest (ANSI), and at various locations in Puslinch Township (five ponds near Crieff), Flamborough (two ponds near Troy), and just outside Paris. Of these sites, Jefferson dependent unisexuals were only captured in the Sudden Bog ANSI. Surveys conducted again in Puslinch Township in 2016 were also negative. Finally, the MNRF sampled three ponds in the Wilmot and Hoffsetter Tracts just west of Kitchener (near Petersburg) in 2017; no Jefferson Salamander or Jefferson dependent unisexuals were captured.

Species and ploidy identification

At the University of Guelph, microsatellite molecular markers for the Jefferson Salamander (Julian et al. 2003) have been, and continue to be, used effectively to identify and distinguish Jefferson Salamanders from Jefferson dependent unisexuals. These markers may also help address other questions regarding population dynamics and genetics that involve the unisexual members of the complex.

Through the Species at Risk Research Fund for Ontario, an Environmental DNA (eDNA) survey protocol was developed and tested (MNRF 2015). This method could be used to rapidly detect genetic material shed by Jefferson Salamanders into the environment and could be used to better understand the distribution and occurrence of the species across its range. The Biodiversity Institute of Ontario at the University of Guelph is currently conducting a study to assess the detection probability of eDNA for Jefferson salamander, quantify the distribution of eDNA across space and time in multiple vernal pools, and to determine if this type of detection is a viable means to monitor this species (S. Crooks pers. comm. 2017).

Apply research findings on the species’ movements and habitat use to ensure protection of habitat

(Recovery Objective 2)

Post-breeding adults

In 2004, the University of Guelph initiated a radio-telemetry study focused on the movement and habitat use of 16 triploid Jefferson dependent unisexual individuals in Halton Region (Bériault 2005). The MNRF continued and expanded the study in 2005, with another 17 Jefferson dependent unisexuals from the same Halton Region location and 19 individuals at two different sites in Peel Region. In 2007 and 2008, MNRF conducted additional radio-telemetry monitoring of both unisexuals and Jefferson Salamanders Halton Region. With a total sample size of 111, these studies have generated extensive data on the movements and terrestrial habitat use of post-breeding adult Jefferson Salamander and Jefferson dependent unisexuals.

Juveniles

In 2015, a multi-year study focused on juvenile dispersal in a population of Jefferson Salamander and Jefferson dependent unisexuals was initiated by Natural Resource Solutions Inc. (NRSI) as a condition of an “overall benefit” 17(2)(c) permit under the ESA 2007. The timing and patterns of dispersal of metamorphs from the study pond were closely monitored by marking and tracking each individual encountered at pitfall trap fences and arrays. This was the first study of its kind in Ontario, and possibly throughout their range, that genetically examined metamorph Jefferson Salamander and Jefferson dependent unisexuals rather than breeding adults.

Fall movements and overwintering locations

In 2017, NRSI conducted a fall radio-telemetry study of adult Jefferson Salamander and Jefferson dependent unisexuals, which provided new insights into fall movements and the location and character of overwintering areas.

Seasonal use of habitats

Patricia Huynh, a PhD Candidate at the University of Waterloo, is exploring the limiting factors of breeding success of Jefferson Salamander by monitoring pool hydrology, water quality, food availability, and juvenile dispersal in vernal pools in the Halton and Peel Regions. This research, which is in its early stages, is in collaboration with Halton Region, Conservation Halton, Credit Valley Conservation, and MNRF.

Stephen Van Drunen, a MSc Candidate in the Norris Lab at University of Guelph, , in collaboration with Natural Resource Solutions Inc., is studying demography, survival and annual movement patterns of Jefferson Salamander and Jefferson dependent unisexuals. This study will use data collected through NRSI’s juvenile dispersal and planned radio-telemetry research.

Develop a communication strategy to inform municipalities, planners, the development industry, property managers and other stakeholders of the habitat mapping and protection requirements for the Jefferson Salamander under the ESA 2007 and other recovery planning initiatives

(Recovery Objective 4)

In May 2003, MNRF ran workshops in Halton Region and Waterloo Region that provided instruction on Jefferson Salamander egg mass identification and outlined the protocol for obtaining samples for genetic analyses. Recovery and Implementation Team members, many of whom are associated with, or work for, regional conservation groups or authorities, attended these workshops.

In Niagara, Halton, and Peel Regions, viewing platforms and interpretive signs have been installed next to Jefferson Salamander breeding ponds to protect them from visitor-related impacts while providing the public with an opportunity to observe and learn about this important species and its habitat. This educational opportunity was promoted through the press for the platform and signs that were installed in the Niagara Region.

A public tour program ran in the Oak Ridges Moraine from 2009 to 2011 to educate the public about the Jefferson Salamander (in addition to other species at risk) and its habitat. This program reached a total of 257 students and members (MNRF 2015).

Over 55 “protection and recovery” 17(2)b permits under the ESA 2007 have been issued by the MNRF pertaining to the Jefferson Salamander (MNRF 2015). These types of permits are issued if the activity of the permit holder would assist in the protection or recovery of the species. These permits enabled a variety of organizations to undertake activities such as conducting surveys to verify and document the locations of Jefferson Salamander populations, restoring habitat, managing invasive species, and installing a boardwalk and fencing to minimize human impacts (MNRF 2015).

Develop and evaluate mitigation and restoration techniques employed to address threats

(Recovery Objective 5)

Road closures

Annual road closures during the spring migration period have been implemented in the City of Burlington and the City of Kitchener to reduce mortalities associated with vehicle traffic. King Road in the City of Burlington has been closed every spring for a period of three weeks since 2012, and was determined to be effective if physical barriers (i.e. cement barriers) were put in place (B. Van Ryswyk pers. comm. 2017).

Stauffer Drive in the community of Doon South in the City of Kitchener has been closed for spring salamander movement formally since 2012 and was informally closed in several springs prior to 2012 (B. Steiner pers. comm. 2018). Road mortality of Ambystomatid salamanders was monitored on Stauffer Drive for five nights each year during their spring migration to/from suitable breeding habitat starting in 2008. This monitoring was originally required and undertaken as a condition of approval of Draft Plans for a Subdivision on the adjacent lands (B. Steiner pers. comm. 2018). From 2012 to 2016, as a condition of an ESA permit for the development north of Stauffer Drive, monitoring was increased to every night of the road closure, which varied year to year depending on weather conditions but generally ran from mid-March through to the first of May. The City anticipates permanently closing this road in 2018 (B. Steiner pers. comm. 2018).

These sorts of measures can be logistically challenging, particularly in years where the conditions suitable for migration occur at atypical times, however the approach and timing of the road closures are adequate to mitigate mortality during peak movements.

Eco-passages

MNRF Aurora District Office has five eco-passages being implemented, under ESA permits to reduce road mortality of Jefferson Salamanders in Peel Region (M. Heaton pers. comm. 2018).

Managing hydroperiod in breeding ponds

Dufferin Aggregates (a division of CRH Canada Group Inc.) has implemented a method to protect and enhance the hydroperiod in Jefferson Salamander breeding pools located near their Milton Quarry Extension. A Water Management System (WMS) was established around the perimeter of the quarry cells, in order to protect offsite water-dependent features (for example creeks, wetlands, Jefferson Salamander breeding pools, etc.) from the dewatering effects of quarrying dolostone from below the water table. The system includes a reservoir that holds groundwater and a system of pump stations, watermains and recharge wells that maintain offsite groundwater levels at seasonal targets and discharges water to nearby wetlands.

This method has proven to be very effective. One pond that was monitored annually from 2003 to 2008 had a suitable hydroperiod for salamander recruitment in only 1 of the 6 years. Since the commencement of WMS in 2009, this pond now has a suitable hydroperiod every year regardless of local climatic conditions and successful salamander breeding has occurred every year which has been confirmed through juvenile recruitment. Artificially maintaining the hydroperiod of salamander breeding ponds with similar WMS may be an important recovery strategy as climate change progressively renders the hydroperiod of more ponds unsuitable for salamander recruitment.

Address emerging pathogens

The Government of Canada has implemented a one-year import restriction on salamanders. The restriction, which is implemented through an amendment to the Wild Animal and Plant Trade Regulations (WAPTR) was approved by the Governor in Council and was published in the Canada Gazette, Part II, on May 31, 2017.

The purpose of the amendment is to prevent the introduction of Batrachochytrium salamandrivorans (Bsal), a pathogenic chytrid fungus that infects salamanders and newts (Palahnuk and Buchanan 2015), into Canadian ecosystems by temporarily prohibiting the import of all species of the order Caudata (such as salamanders, newts and mudpuppies) unless authorized by a permit issued by Environment and Climate Change Canada, for a period of one-year, until May 11, 2018.

During this time, the Government of Canada will explore longer-term measures to protect Canadian salamanders. Prohibiting the import of all salamander species is consistent with the precautionary principle, and takes into consideration the limited and evolving understanding of the disease, as well as the enforcement challenges associated with identifying different salamander species at Canada’s numerous ports of entry.

2.0 Recovery

2.1 Recommended recovery goal

The recommended recovery goal is to ensure that existing threats to populations and habitat of the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) are sufficiently removed to allow populations to become stable or increase in abundance and distribution throughout Ontario.

2.2 Recommended protection and recovery objectives

The focus of the short-term recovery objectives, and the recommended overall recovery goal, is the protection of existing populations of the Jefferson Salamander and Jefferson dependent unisexuals by ensuring that no further loss or degradation of known habitat or potentially suitable habitat (recovery habitat) occur. Habitat protection is critical to the survival of these species. Protection of existing habitat and enforcement of the habitat regulation should have priority over compensation for lost habitat (that is, the creation of habitat). Consistent with general principles of conservation biology for species at risk, the avoidance of negative impacts should be the first approach and compensatory measures such as habitat creation and species relocation efforts should be undertaken only as a last resort and when other measures (for example, mitigation) have proven unsuccessful.

Protection, restoration and enhancement of existing Jefferson Salamander and Jefferson dependent unisexual habitat are the priority recovery planning recommendations. Habitat alterations that would adversely affect these species should be discouraged.

Although habitat created through the permitting process is protected as part of the overall benefit for the species, at present, there is no basis for protecting other newly created features (for example, breeding ponds) because colonization and use of such features has not been sufficiently documented. Created habitat cannot immediately replace existing habitat that Jefferson Salamanders use. In addition, restoration of forests and wetlands over the long-term (that is, 50+ years) intended to compensate for habitat loss are not in keeping with recovery planning for Jefferson Salamander, Jefferson dependent unisexuals and other species at risk.

2.3 Recommended approaches to recovery

Table 6 of part 2. Recommended approaches to recovery of the Jefferson Salamander and Jefferson dependent unisexuals in Ontario

2.4 Area for consideration in the development of the habitat regulation

Under the ESA, a recovery strategy must include a recommendation to the Minister of Natural Resources and Forestry on the area that should be considered in developing a habitat regulation. A habitat regulation is a legal instrument that prescribes an area that will be protected as the habitat of the species. The recommendation provided below by the author will be one of many sources considered by the Minister when developing the habitat regulation for this species.

On February 18, 2010, the following habitat regulation came into force under the ESA 2007 for the Jefferson Salamander (O. Reg. 242/08):

Jefferson salamander habitat

28. For the purpose of clause (a) of the definition of “habitat” in subsection 2 (1) of the Act, the following areas are prescribed as the habitat of the Jefferson salamander:

1. In the City of Hamilton, the counties of Brant, Dufferin, Elgin, Grey, Haldimand, Norfolk and Wellington and the regional municipalities of Halton, Niagara, Peel, Waterloo and York,
   1. a wetland, pond or vernal or other temporary pool that is being used by a Jefferson salamander or Jefferson dominated polyploid or was used by a Jefferson salamander or Jefferson dominated polyploid at any time during the previous five years
   2. an area that is within 300 metres of a wetland, pond or vernal or other temporary pool described in subparagraph i and that provides suitable foraging, dispersal, migration or hibernation conditions for Jefferson salamanders or Jefferson dominated polyploids
   3. a wetland, pond or vernal or other temporary pool that,
      1. would provide suitable breeding conditions for Jefferson salamanders or Jefferson dominated polyploids
      2. is within one kilometre of an area described in subparagraph i, and
      3. is connected to the area described in subparagraph i by an area described in subparagraph iv, and
   4. an area that provides suitable conditions for Jefferson salamanders or Jefferson dominated polyploids to disperse and is within one kilometre of an area described in subparagraph i

Although the Jefferson dependent unisexuals were not protected under the ESA 2007 at the time the regulation came into force, their presence triggered the application of the habitat regulation. This is because the presence of Jefferson dependent unisexuals indicates the presence of Jefferson Salamander at some point in time (Bogart et al. 2017).

Considerations for the refinement of the habitat regulation:

The current regulation is effective at protecting both Jefferson Salamander and Jefferson dependent unisexuals, however the following amendments should be considered:

• Jefferson dependent unisexuals should be added as a distinct taxon to which the regulation applies
• the terminology in the regulation should be updated to replace “Jefferson dominated polyploids” with Unisexual Ambystoma (Jefferson Salamander dependent population) for consistency
• the Municipality of Chatham-Kent, Durham Region, and Oxford and Perth Counties should be added to the areas in which the regulation applies

Exclusions

The following features should not be included within the habitat regulation:

• existing houses, buildings, and structures that are within 300 m of a breeding pond
• open areas such as agricultural fields that are within 1 km of a breeding pond that do not directly separate the pond from forested areas or other breeding ponds and therefore do not serve as corridors between habitats and/or breeding areas

Naturalized anthropogenic features

Jefferson Salamanders and Jefferson dependent unisexuals occasionally breed in old farm ponds and human-created depressions that have reached a substantial state of wetland succession (probably after decades) and that occur within, or close to, existing forested or other naturally vegetated areas. Most of these ponds/depressions occur in locations where wetlands had originally existed or where portions of wetlands have been deepened. The vast majority of wetlands on the landscape that existed before agricultural conversion have been eliminated and at higher rates in areas where drainage and filling has been feasible and practicable. Therefore, these salamanders may use some naturalized human-created depressions as breeding habitat. Naturalized anthropogenic features such as old farm ponds and human-created depressions where Jefferson Salamanders and Jefferson dependent unisexuals are confirmed to breed should be included in the habitat regulation.

Glossary

Bisexual species:

The condition of an organism capable of producing both male and female gametes (sex cells)

Extant population:

A population that has been confirmed in the last 20 years

Chromosome:

A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes

Committee on the Status of Endangered Wildlife in Canada (COSEWIC):

The committee established under section 14 of the Species at Risk Act that is responsible for assessing and classifying species at risk in Canada

Committee on the Status of Species at Risk in Ontario (COSSARO):

The committee established under section 3 of the ESA, 2007 that is responsible for assessing and classifying species at risk in Ontario

Conservation status rank:

A rank assigned to a species or ecological community that primarily conveys the degree of rarity of the species or community at the global (G), national (N) or subnational (S) level. These ranks, termed G-rank, N-rank and S-rank, are not legal designations. Ranks are determined by NatureServe and, in the case of Ontario’s S-rank, by Ontario’s Natural Heritage Information Centre. The conservation status of a species or ecosystem is designated by a number from 1 to 5, preceded by the letter G, N or S reflecting the appropriate geographic scale of the assessment. The numbers mean the following:

1 = critically imperilled
2 = imperilled
3 = vulnerable
4 = apparently secure
5 = secure
NR = not yet ranked

Conspecific:

A member of the same species

Control site:

A study site against which all other study sites will be compared. In the case of the Jefferson Salamander, a control site is one where conditions are known to be typical for the species and where there is a lack of disturbance

Demography:

Demography is the study of the size, structure, and distribution of populations, and population changes in space and time in response to birth, death, aging, and migration

Diploid:

When an organism has two complete sets of chromosomes, one from each parent

Element occurrence:

As used by NatureServe conservation data centers, an occurrence of an element of biodiversity (for example, species or ecological community) on the landscape, an area of land and/or water on/in which an element is or was present. The NHIC uses a 1 kilometre radius to define element occurrences of the Jefferson Salamander in Ontario

Endangered Species Act, 2007 (ESA):

The provincial legislation that provides protection to species at risk in Ontario

Extant:

Still in existence; not extirpated

Extirpated:

Species, community or population is believed to be lost from the nation, state/province or site

Genomotype:

The genetic constitution of an individual organism

Gynogenetic development:

Development in which the embryo contains only maternal chromosomes due to activation of an egg by a sperm that degenerates without fusing with the egg nucleus

Historic population:

A population that has not been confirmed in the last 20 years but is not yet confirmed as extirpated

Hydroperiod:

The duration, depth and extent of saturation of water in a vernal pool or other wetland

Isozymes:

Each of two or more enzymes with identical function but different structure, from different genes such that they can be used for identification of species

Juvenile:

An individual in its second, or subsequent years, which has not yet reached sexually maturity

Kleptogenesis:

Reproduction by a unisexual species using sperm 'stolen' by mating with members of a related bisexual species

Metamorph:

An individual that has recently transformed or completed metamorphosis

Metamorphosis:

The process of transformation from an immature form to an adult form in two or more distinct stages. In salamanders, metamorphosis is the process where an individual changes from a gilled larva into a juvenile that lacks gills

Microsatellite DNA:

A section of repetitive DNA widely used for DNA profiling in population genetics, in which certain DNA motifs (ranging in length from 2–5 base pairs) are repeated, typically 5–50 times

Mitochondrial lineage:

Mitochondrial DNA is the DNA located in mitochondria, cellular organelles within cells that convert chemical energy from food into a form that cells can use. In most species, mitochondrial DNA is inherited solely from the mother, leading to distinguishable lineages of related organisms

Monophyletic:

A group of organisms descended from a common evolutionary ancestor or ancestral group

Morphology:

They physical form of living things

Natal:

Relating to the place or time of an organism’s birth

Pentaploid:

When an organism has five complete sets of chromosomes

Ploidy:

The number of sets of chromosomes in a cell, or in the cells of an organism

Polyploid:

[Of] An organism that contains more than two sets of chromosomes (for example, triploid – three sets of chromosomes, tetraploid – four sets of chromosomes). Examples within the Ambystoma laterale–jeffersonianum complex include LJJ, LLJ, LJJJ, and so on

Population:

For the purposes of this report, a population is defined as a group of salamanders that use one or many breeding ponds in a contiguous area of suitable habitat

Recruitment:

When juvenile organisms survive to be added to a population, by birth or immigration

Refugia:

Areas in which organisms can survive through a period of unfavorable conditions

Site:

For the purposes of this report, a site is defined as a single salamander breeding pond or group of breeding ponds that function to support a subpopulation

Skeletochronology:

Used to determine the chronological age of an organism by counting the concentric growth rings found in a cross section of bone

Species at Risk Act (SARA):

The federal legislation that provides protection to species at risk in Canada. This act establishes Schedule 1 as the legal list of wildlife species at risk. Schedules 2 and 3 contain lists of species that at the time the Act came into force needed to be reassessed. After species on Schedule 2 and 3 are reassessed and found to be at risk, they undergo the SARA listing process to be included in Schedule 1

Species at Risk in Ontario (SARO) List:

The regulation made under section 7 of the ESA, 2007 that provides the official status classification of species at risk in Ontario. This list was first published in 2004 as a policy and became a regulation in 2008

Spermatophore:

A capsule of sperm on a gelatinous base that male salamanders deposit on the substrate of a breeding pond for females to take up

Snout to vent length (SVL):

A standard measurement of an animal’s body length. The measurement is from the tip of the nose (snout) to the cloaca (vent), and excludes the tail

Subpopulation:

For the purposes of this report, a subpopulation is the group of salamanders that use a particular breeding pond or set of breeding ponds within 1km of each other

Sympatric:

Occurring within the same geographical area, overlapping in distribution

Triploid:

When an organism has three complete sets of chromosomes

Tetraploid:

When an organism has four complete sets of chromosomes

Unisexual Ambystoma:

A female member of the Ambystoma laterale–jeffersonianum complex that uses a form of reproduction whereby sperm is required to stimulate egg development but the male’s genes are normally not incorporated. The offspring are genetically identical to their mothers

Vernal pool:

Also known as an “ephemeral wetland,” a landform depression that temporarily fills with water following snowmelt in the spring and heavy rainfall or as a result of a high water table. Vernal pools vary in their size, shape, depth, timing and duration of flooding, and the types of species that are able to use them. A defining feature of vernal pools is that they usually dry by the middle of the summer, some vernal pools, however, may dry only every couple of years

Water balance:

In hydrology, the term water balance refers to the flow of water into and out of a system. Water sources include groundwater, surface water and precipitation while water losses can occur through evaporation, plant transpiration from plants, runoff, or drainage

References

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List of abbreviations

COSEWIC:

Committee on the Status of Endangered Wildlife in Canada

COSSARO:

Committee on the Status of Species at Risk in Ontario

CWS:

Canadian Wildlife Service

ESA:

Ontario Endangered Species Act, 2007

ISBN:

International Standard Book Number

IUCN:

International Union for Conservation of Nature and Natural Resources

MNRF:

Ontario Ministry of Natural Resources and Forestry

NHIC:

Natural Heritage Information Centre

SARA:

Canadian Species at Risk Act

SARO:

Species at Risk in Ontario

Part 3 – Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) – Ontario Government Response Statement, prepared by the Ontario Ministry of the Environment, Conservation and Parks, 2019

Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) 
Ontario government response statement

Protecting and recovering species at risk in Ontario

Species at risk recovery is a key part of protecting Ontario’s biodiversity. The Endangered Species Act, 2007 (ESA) is the Government of Ontario’s legislative commitment to protecting and recovering species at risk and their habitats.

Under the ESA, the Government of Ontario must ensure that a recovery strategy is prepared for each species that is listed as endangered or threatened. A recovery strategy provides science-based advice to government on what is required to achieve recovery of a species.

Within nine months after a recovery strategy is prepared, the ESA requires the Ontario government to publish a statement summarizing the government’s intended actions and priorities in response to the recovery strategy. The response statement is the government’s policy response to the scientific advice provided in the recovery strategy. In addition to the strategy, the government response statement considered (where available) input from Indigenous communities and organizations, stakeholders, other jurisdictions, and members of the public. It reflects the best available local and scientific knowledge, including Traditional Ecological Knowledge where it has been shared by communities and Knowledge Holders, as appropriate and may be adapted if new information becomes available. In implementing the actions in the response statement, the ESA allows the government to determine what is feasible, taking into account social, cultural and economic factors.

The Recovery Strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale – (2) jeffersonianum) in Ontario was completed on May 30, 2018. Given the similar distribution and threats, the recovery efforts for Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) are addressed collectively in a single government response statement. The government response statement for Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) builds on and replaces the existing government response statement for Jefferson Salamander (2010).

In 2010, the Government of Ontario developed a government response statement in response to the Recovery Strategy for the Jefferson Salamander in Ontario (2010). Since that time, progress has been made toward all government-led actions and several of the government-supported actions outlined in the GRS. Through the Species at Risk Stewardship Fund, the Ontario government has supported a total of 40 projects designed to contribute to the protection and recovery of Jefferson Salamander. Three of these projects focused exclusively on the species, while the other 37 projects focused on multiple species at risk, including Jefferson Salamander. For a complete summary of the progress that has been made toward the protection and recovery of Jefferson Salamander in Ontario please see the 2015 Five-Year Review of Progress.

Jefferson Salamander is a relatively large, uniformly grey to brownish-grey mole salamander with variable amounts of grey-blue speckling along the sides of the body and tail. The Unisexual Ambystoma (Jefferson Salamander dependent population), which co-exist with Jefferson Salamanders, are morphologically similar but genetically distinct. In Canada, the two species’ have only been found in Southern Ontario, mainly along the Niagara Escarpment.

Protecting and recovering Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population)

Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) (also referred to hereafter as Jefferson dependent unisexuals) are listed as endangered species under the ESA, which protects both the salamanders and their habitat. The ESA prohibits harm or harassment of the species and damage or destruction of their habitat without authorization. Such authorization would require that conditions established by the Ontario government be met. In addition to protection under the ESA, Jefferson Salamander is also listed under Schedule 10 of the Fish and Wildlife Conservation Act (FWCA) as a Specially Protected Amphibian.

The global distribution of the Jefferson Salamander is restricted to eastern North America. In Canada, they are only known to occur in southern Ontario, which represents the northern extent of the species’ range. Jefferson dependent unisexuals are found in association with Jefferson Salamander populations throughout the Jefferson Salamander range. In Ontario, Jefferson Salamander and Jefferson dependent unisexuals generally occur in the eastern portion of the Carolinian zone and along the Niagara Escarpment. There are also geographically isolated populations dispersed throughout the range. Present knowledge indicates that the current isolated sub-populations of these species are remnants of what was once a more extensive, continuous range throughout southern Ontario. Recent estimates for Jefferson Salamander suggest a decline of more than 90 percent over the last three generations (33 years) of this species in Ontario. Within their distribution in Ontario, both salamanders co-occur and are only differentiated from each other through genetic analysis.

Jefferson Salamander and Jefferson dependent unisexuals are members of the Mole Salamander family (Ambystomatidae), a family name that refers to spending the majority of their time underground or beneath cover except when breeding.

All Unisexual Ambystoma (Jefferson Salamander dependent population) salamanders are females and have a unique reproductive strategy whereby the sperm from male Jefferson Salamanders is needed to initiate egg development. Their offspring are unique in that they are also all females. While the sperm may or may not be incorporated into the Jefferson dependent unisexual egg, the species does not appear to be able to reproduce in the absence of a Jefferson Salamander. Therefore, the persistence of the Unisexual species is dependent on the presence of Jefferson Salamander.

Jefferson Salamander and Jefferson dependent unisexuals are the earliest of the mole salamanders to arrive at breeding ponds in the spring. They typically migrate to breeding ponds during the first rainy nights of the spring when temperatures are above freezing. Jefferson dependent unisexuals appear to exhibit the same behaviours as Jefferson Salamanders throughout their life cycle. Breeding commences when groups of adults gather in a breeding pond; males deposit sperm capsules on the pond substrate, which are picked up by the females. Within a day or two, females deposit egg masses on twigs or emergent vegetation. In Ontario, transformation from the aquatic (larval) to terrestrial body form normally occurs in July and August. After transformation the salamanders move out of the pond and seek shelter in forested areas, where they spend most of their time underground. Jefferson Salamanders, especially females, do not breed every year and breeding success varies depending on spring weather and water-levels.

Adult Jefferson Salamanders and Jefferson dependent unisexuals are found within deciduous or mixed upland forests containing, or adjacent to, suitable breeding ponds. Breeding ponds are typically ephemeral, or vernal, woodland pools that dry in late summer. Terrestrial habitat is in mature woodlands that have small mammal burrows or rock fissures that enable adults to overwinter underground below the frost line.

In Ontario, the Jefferson Salamander and Jefferson dependent unisexuals are limited by availability of suitable habitat. The vast majority of suitable habitat in Ontario has been cleared, initially for agriculture and subsequently for urban development and there remains high development pressure on the limited remaining habitat. Key knowledge gaps include the effectiveness of mitigation measures to address threats, information on the species’ movements including dispersal patterns, timing and distances, and habitat use, particularly the location and characteristics of overwintering habitat.

The primary threats to the two species include habitat loss, degradation, and fragmentation of woodlands and breeding ponds, road-related threats (for example, vehicles and pollutants) and changes in pond hydrology. Other threats may include forestry activities, recreational activities, unauthorized collection, invasive and introduced species, agricultural land uses and climate change.

Currently there is insufficient science to support whether or not created features (for example, artificial breeding ponds) can be successfully colonized. Given this, efforts to recover Jefferson Salamander and Jefferson dependent unisexuals will be focused on promoting the conservation and protection of existing populations and habitat, rather than creating new habitat. Priority will be given to reducing primary threats (i.e., road mortality, habitat degradation) and curtailing further loss or degradation of known habitat or potentially suitable habitat in areas where the species occurs or where their range is likely to naturally expand. Improving habitat connectivity will help enable the species’ to naturally recolonize areas where they formerly occurred or where there is suitable habitat adjacent to occupied sites. Approaches to recovery will include continued inventory and monitoring, reducing threats to Jefferson Salamander and Jefferson dependent unisexuals and their habitat, filling knowledge gaps and increasing levels of engagement and awareness.

Government’s recovery goal

The government’s goal for the recovery of the Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) is to ensure long-term viability and persistence of the extant distribution, and to support the expansion of the species’ range to include historically-occupied areas in Ontario.

This will be achieved through approaches such as removing or sufficiently mitigating high priority threats, enhancing or restoring habitat and improving habitat connectivity.

Actions

Protecting and recovering species at risk is a shared responsibility. No single agency or organization has the knowledge, authority or financial resources to protect and recover all of Ontario’s species at risk. Successful recovery requires inter-governmental co-operation and the involvement of many individuals, organizations and communities. In developing the government response statement, the government considered what actions are feasible for the government to lead directly and what actions are feasible for the government to support its conservation partners to undertake.

Government-led actions

To help protect and recover Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population), the government will directly undertake the following actions:

• continue to protect Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) and their habitat through the ESA. Amend the 2010 habitat regulation for Jefferson Salamander to include the Unisexual Ambystoma (Jefferson Salamander dependent population) and expand the geographic scope to areas where the species have been newly discovered. Continue to implement, promote compliance with and enforce habitat protections using the species-specific habitat regulation
• ensure appropriate timing windows as well as additional avoidance and/or mitigation measures are considered in the application of the ESA for activities undertaken in and around Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) habitat
• continue monitoring, restoration and awareness efforts in protected areas where Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) have been found
• educate other agencies and authorities involved in planning and environmental assessment processes on the protection requirements under the ESA
• encourage the submission of Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) data to Ontario’s central repository through the citizen science projects that they receive data from (for example, iNaturalist) and directly through the Natural Heritage Information Centre
• undertake communications and outreach to increase public awareness of species at risk in Ontario
• support conservation, agency, municipal and industry partners, and Indigenous communities and organizations to undertake activities to protect and recover Jefferson salamander and Unisexual Ambystoma (Jefferson Salamander dependent population). Support will be provided where appropriate through funding, agreements, permits (including conditions) and/or advisory services
• encourage collaboration, and establish and communicate annual priority actions for government support in order to reduce duplication of efforts

Government-supported actions

The government endorses the following actions as being necessary for the protection and recovery of Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population). Actions identified as “high” may be given priority consideration for funding under the Species at Risk Stewardship Program. Where reasonable, the government will also consider the priority assigned to these actions when reviewing and issuing authorizations under the ESA. Other organizations are encouraged to consider these priorities when developing projects or mitigation plans related to species at risk.

Focus area: Research, monitoring and population management

Objective: Increase knowledge of Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) distribution, biology, habitat requirements, threats, and limiting factors.

Although progress has been made toward the development of a standardized survey protocol, further action is required to implement the protocol to fill knowledge gaps around the species’ current distribution and range in Ontario, particularly in portions of the Oak Ridges Moraine and Greenbelt Plan areas. Knowledge gaps also exist around the species’ spatial ecology, including dispersal patterns, timing and distances. Confirming where the species are present and the habitat requirements for all life stages will help determine where recovery efforts are best focused. Implementation of a standardized long-term monitoring program will aid in understanding the status of both species, the effectiveness of recovery efforts, and determine whether habitat management actions may be required. Monitoring the proportion of Jefferson Salamander and Jefferson dependent unisexuals within sample populations will help fill knowledge gaps in trends in these data over time. Jefferson Salamander and Jefferson dependent unisexuals are limited by the amount of suitable habitat. Understanding mitigation strategies to protect breeding pond hydrology will assist in ensuring suitable habitat is available for the full duration of the breeding period.

Actions:

1. (High) Implement a standardized survey protocol (i.e., presence/absence) to verify historic populations and document potential new populations of Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population).

2. (High) Continue to research the species’ movements and habitat use to inform habitat protection, including investigation of habitat needs for all life-stages and life processes.

3. Develop a standardized long-term monitoring protocol and monitoring schedule to be implemented at subpopulations throughout the species’ range. Monitoring activities could include assessment of:

• species presence/absence
• population viability, recruitment and distribution
• site-specific threats
• trends in habitat condition and use; and
• changes in proportional abundance of Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population)

4. Investigate, implement where appropriate and test the effectiveness of mitigation approaches to reduce or avoid impacts to breeding pond hydrology. Actions may include:

• identifying mitigation strategies (for example, water management systems) to ensure sufficient quantity and duration of water present in breeding ponds adjacent to industry activities; and
• addressing or mitigating the potential impacts of climate change on pond hydrology

5. Investigate the effects and severity of additional known and potential threats to Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population), including:

• the potential effects of introduced or invasive species; and
• the potential effects of environmental contaminants, disease and parasites

6. Investigate the ecological relationship between Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) to assess potential demographic constraints to species’ recovery (for example, related to reproductive output, recruitment, and survival in the larval and adult life stages).

7. Investigate the potential need for, feasibility of and likely success of assisted recruitment techniques at existing sites to support the recovery goal for Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population). If found to be feasible and necessary, implement, evaluate, adapt and improve recruitment techniques with consideration for Jefferson Salamander ecology and the Unisexual Ambystoma (Jefferson Salamander dependent population) as a whole. An example of a priority recruitment technique is:

• exploring the potential benefits and need for a cost-effective head-starting protocol/program (for example, reproductive monitoring, artificial incubation of eggs, and release of juveniles)

Focus area: Habitat and threat management

Objective: Maintain or improve habitat quality and reduce threats to Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population).

Habitat loss, fragmentation and degradation are considered the greatest threats to Jefferson Salamander and Jefferson dependent unisexuals across their global range, including Ontario. Developing, implementing and evaluating practical actions that municipalities, developers, academics, conservation partners and the public can undertake to address high priority threats, such as road mortality, will help support the protection and recovery of these species. Promoting beneficial actions that stakeholders, land managers and Indigenous communities and organizations can take proactively to enhance and restore habitat and improve habitat connectivity are also encouraged.

Actions:

8. (High) Collaborate with municipalities, developers, local organizations and members of the public to mitigate the effects of roads. Actions may include:

• developing, implementing and evaluating the effectiveness of best management practices and techniques to reduce road mortality (for example, ecopassages, barrier fencing, traffic calming measures, seasonal closures) particularly in areas of high mortality
• installing permanent control measures to prevent sediment and pollution from roads from entering breeding ponds; and
• developing programs or campaigns to reduce road mortality, which may include installing signs and publicizing the need for cautious driving, particularly in areas of high mortality

9. (High) Collaborate with local groups and land managers to assess current, historic and presently unoccupied areas with suitable habitat and identify candidate areas for habitat enhancement and restoration, prioritizing currently occupied habitat. This may involve identifying site-specific restoration needs and goals and developing restoration plans. Actions could include:

• targeting removal of fish or invasive species from breeding ponds using appropriate and approved methods
• creating a mosaic of suitable habitat with a focus on increasing connectivity between suitable habitat patches; and
• applying techniques to ensure sufficient water levels and quality in breeding ponds during the breeding season. This may include buffering for the potential effects of climate change on water levels in the future and exploring opportunities to support hydrology at a watershed scale (for example, restoring riparian habitat)

10. Develop, implement and evaluate best management practices and techniques to mitigate impacts of additional threats (for example, industry activities, recreational use) on Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) individuals and their habitat.

Focus area: Awareness

Objective: Increase public awareness and promote protection of Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population) and their habitats in Ontario.

Increasing awareness amongst local land managers, municipalities and developers and promoting integration with other relevant planning processes are critical to addressing key threats such as habitat loss and road mortality. Raising awareness amongst the public, local land owners and organizations of Jefferson Salamander and Jefferson dependent unisexuals, as well as how to reduce threats to the species’ and how to enhance their habitat will help promote and encourage protection of the species’ and their habitat in Ontario.

Actions:

11. (High) Support the development of tools and approaches for municipalities, planning authorities, industries, property managers and other stakeholders to ensure habitat mapping and protection requirements under the ESA are integrated into official plans and other relevant planning processes.

12. Identify communication needs and develop products that will provide information and resources to landowners, property managers, the aggregate industry, local stewardship councils, local conservation authorities and other stakeholders to assist in recovery efforts and promote land stewardship.

Implementing actions

Financial support for the implementation of actions may be available through the Species at Risk Stewardship Program. Conservation partners are encouraged to discuss project proposals related to the actions in this response statement with program staff. The Ontario government can also advise if any authorizations under the ESA or other legislation may be required to undertake the project.

Implementation of the actions may be subject to changing priorities across the multitude of species at risk, available resources and the capacity of partners to undertake recovery activities. Where appropriate, the implementation of actions for multiple species will be co-ordinated across government response statements.

Reviewing progress

The ESA requires the Ontario government to conduct a review of progress towards protecting and recovering a species not later than five years from the publication of this response statement. The review will help identify if adjustments are needed to achieve the protection and recovery of Jefferson Salamander and Unisexual Ambystoma (Jefferson Salamander dependent population).

Acknowledgement

We would like to thank all those who participated in the development of the Recovery Strategy for the Jefferson Salamander (Ambystoma jeffersonianum) and Unisexual Ambystoma (Jefferson Salamander dependent population) (Ambystoma laterale – (2) jeffersonianum) in Ontario for their dedication to protecting and recovering species at risk.

For additional information

Visit the species at risk website at Ontario Species at risk

Contact the Natural Resources Information Centre

1-800-667-1940

TTY 1-866-686-6072

mnr.nric.mnr@ontario.ca