Greenish-white Grasshopper (Hypochlora alba): management plan [proposed] 2022

Official title: Management Plan for the Greenish-white Grasshopper (Hypochlora alba) in Canada

Species at Risk Act

Management Plan Series

Proposed

2022

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 management plans for listed species of special concern and are required to report on progress within five years after the publication of the final document on the SAR Public Registry.

The Minister of Environment and Climate Change and Minister responsible for the Parks Canada Agency is the competent minister under SARA for the Greenish-white Grasshopper and has prepared this management plan as per section 65 of SARA. To the extent possible, it has been prepared in cooperation with the provinces of Alberta, Saskatchewan, and Manitoba as per section 66(1) of SARA.

Success in the conservation 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 plan and will not be achieved by Environment and Climate Change Canada and the Parks Canada Agency or any other jurisdiction alone. All Canadians are invited to join in supporting and implementing this plan for the benefit of the Greenish-white Grasshopper and Canadian society as a whole.

Implementation of this management plan is subject to appropriations, priorities, and budgetary constraints of the participating jurisdictions and organizations.

Acknowledgments

This document was prepared by Lynne Burns (Environment and Climate Change Canada (ECCC), Canadian Wildlife Service – Prairie Region), with assistance from Sarah James (ECCC) and Mark Wayland (retired from ECCC). Valuable reviews were provided by Yeen Ten Hwang, Medea Curteanu, Angela Barakat (ECCC), Joanne Tuckwell (Parks Canada Agency), James Tansey and Jeff Keith (Government of Saskatchewan), Nicole Firlotte and Chris Freisen (Manitoba Agriculture and Resource Development) and Dan Johnson (University of Lethbridge). The Manitoba Conservation Data Centre provided updated element occurrences. Thanks are extended to Dan Johnson (University of Lethbridge) for providing species information, including records and photographs. Thanks are also extended to Owen Lonsdale (Agriculture and Agri-Food Canada) for providing records from the Canadian National Collection of Insects, Arachnids, and Nemtodes, and to Stéphanie Boucher (Lyman Entomological Museum, McGill University),Jason Gibbs (Wallis Roughley Museum of Entomology, University of Manitoba), Laura Burns (Assiniboine Park Zoo), Kerry Hecker and Rachel Turnquist (ECCC) and Stefano Liccioli (PCA) for providing Canadian records of the species. Also thanks to Michael Fitzsimmons, Joseph Kotlar, and Rachel Turnquist (all of ECCC) and to Scott Hartley, Trevor Lennox and James Tansey (all of Saskatchewan Agriculture) for information about pesticide use in rangeland habitat. Jeff Harder and Elizabeth Beck (ECCC) are acknowledge for help creating the maps.

Executive summary

Greenish-white Grasshopper (Hypochlora alba) is a small, distinctive, pale milky-green coloured Orthopteran insect. The colouration closely matches that of the host plant, White Sagebrush (Artemisia ludoviciana), that the species relies on for multiple life stages. Greenish-white Grasshopper is a late-hatching species (mid-July) and females are typically larger than males.

The species’ distribution in Canada is small being known only from southern Alberta, Saskatchewan, and Manitoba. The distribution is at the northern periphery of the species global range. Existing records encompass 47 sites where Greenish-white Grasshoppers have been observed in Canada, including 33 from 2010 until 2021, eight from 1985-2009 and six historical sites prior to 1985. Greenish-white Grasshopper is listed as a species of Special Concern under the Species at Risk Act (SARA).

The most significant limiting factors for Greenish-white Grasshopper are its reliance on a single host plant that occurs in patches of low densities, and a low dispersal ability to move among habitat patches. With a reliance on one main host plant, any threats to this host plant constitute a threat to this rare grasshopper. Several poorly understood threats have been identified for Greenish-white Grasshoper including habitat loss, degradation or fragmentation from grassland conversion to cultivated crops; herbicide and pesticide use; road construction or maintenance; and oil and gas drilling. Other threats that result in changes to the natural disturbance regime include enhancing forage production in pastures, or changes to grazing or fire regimes, landscape hydrology and climate.

The management objective for Greenish-white Grasshopper is to maintain the distribution of the species, based on records from 1985 until 2021, in Alberta, Saskatchewan and Manitoba, as well as any additional populations that are discovered or rediscovered in the future.

Broad strategies to address the threats and attain the management objective include inventory and monitoring, research to address knowledge gaps of the species and its habitat, habitat management and conservation, and lastly communication, collaboration and engagement. Conservation measures are described to address these broad strategies.

1. COSEWIC* species assessment information

Date of assessment: November 2012

Common name (population): Greenish-white Grasshopper

Scientific name: Hypochlora alba

COSEWIC status: Special Concern

Reason for designation: This distinctive grasshopper is restricted to dry mixed grass prairie in southernmost Saskatchewan and southwestern Manitoba. Most of the Canadian population is found in only a few sites with many sites having very small populations. There is evidence that there has been a decline in the western part of the range. A number of threats have been documented including conversion to tame pasture, pesticide use and overgrazing. Re-establishment of lost populations and rescue effect are limited by the fact that this species is mostly flightless, although some Canadian habitat is continuous across the border.

Canadian occurrence: Alberta, Saskatchewan, Manitoba

COSEWIC status history: Designated Special Concern in November 2012.

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

2. Species status information

In Canada, Greenish-white Grasshopper (Hypochlora alba) was listed as Special Concern under Schedule 1 of the Species at Risk Act (SARA) on February 2, 2018. It is estimated that approximately 5.7 % of the range of the Greenish-white Grasshopper occurs in Canada (based on global range boundaries in Pfadt 1996 and Capinera et al. 2004). However, this is difficult to estimate since the species distribution and abundance is not known in many states in the United States.

NatureServe (2021) designates a ranking of the global population of Greenish-white Grasshopper as Secure (G5; status last reviewed 2017). Nationally the species is ranked as Apparently Secure or Secure (N4N5) in Canada and Secure (N5) in the United States (Nature Serve 2021). Table :1 describes the NatureServe status rankings of the species at the sub-national level for provinces and states where the status is defined.

Greenish-white Grasshopper is not listed in any of the provinces where it is found. In Alberta, the Pest and Nuisance Control 184/2001 Regulations under the Agricultural Pests Act list Grasshopper (Locustidae) under Schedule 1, Part 1 as insects declared to be pests throughout Alberta. In Saskatchewan, The Pests Declaration Regulations Chapter P-7 REG 2 list grasshoppers (Section 2 (c)) as declared pests for the purposes of The Pest Control Act. Despite a broad listing of grasshoppers as pests in these provinces, Greenish-white Grasshopper has not had any significant pest status attributed to it in North America (COSEWIC 2012). This is because it does not feed on economically important plant species in any appreciable amount to cause high levels of damage requiring population suppression measures or interventions.

3. Species information

3.1 Species description

The Greenish-white Grasshopper is an insect that is a member of Order Orthoptera (grasshoppers, locusts, crickets and katydids), and is placed in the Family Acrididae (short-horned grasshoppers). Within the Acrididae, it is further placed in the Subfamily Melanoplinae, the spur-throated grasshoppers (COSEWIC 2012). Members of this subfamily have a characteristic ventral spine or spur between their front legs, in a position approximating the location of the throat (Johnson 2002). It is the only member of the genus Hypochlora that is found in North America.

While generally known as the Greenish-white Grasshopper in Canada, it is also known by several other common names. This includes the Sage Grasshopper in Alberta and Manitoba (ACIMS 2017, MB CDC 2017), Cudweed Grasshopper in Saskatchewan (SK CDC 2017), and Cudweed Sagewort Grasshopper or Sagebrush Grasshopper in the U.S. These names reflect the close association with its host plant, White Sagebrush (Artemisia ludoviciana) which is also known as Cudweed Sagewort and Prairie Sage (Knutson 1982, Pfadt 1996).

Greenish-white Grasshopper displays a typical grasshopper life cycle as it is univoltine, having one generation per year, composed of 3 stages: egg, nymph (consisting of several immature stages) and adult (Criddle 1935, Pfadt 1994). The nymph stage represents a gradual metamorphosis from hatchling to adult. Each immature stage resembles a smaller version of the adult where every sequential nymphal stage shows a successive increase in size. In Canada the first nymphs hatch from eggs (the overwintering stage) in mid-July with adults being observed on the landscape by August (COSEWIC 2012). This timing makes them a late-developing grasshopper species.

Adults -The colouring of the adult Greenish-white Grasshopper is cryptic as it closely matches the milky-green colouring of its primary host plant, White Sagebrush, making it difficult to distinguish when on the plant (Smith and Grodowitz 1987). Adult Greenish‑white Grasshoppers are small, generally flightless grasshoppers with greatly reduced forewings. Females occasionally are encountered with long wings but this is infrequent (Pfadt 1996). Males are typically smaller compared to females in overall length (males 1.1 to 1.5 cm, females up to 2.0 cm; D. Johnson pers. comm) and weight (males 122 mg, females 326 mg; Pfadt 1996).

The body is an overall pale milky-green colour with a broad green band running from behind the eyes on each side of the body to the pronotum (a saddle shaped structure of the thoracic region^{Footnote 3}) (Figure 1; Pfadt 1996). A white stripe on either side of the body gives the appearance of four light green stripes when viewed from above. The eye is grey to tan and the legs are light green in colour, but may be slightly darker green than the body (COSEWIC 2012). In Canadian populations, the antennae are reddish-brown/tan through to grey in adults but these may be more green in southerly U.S. populations (COSEWIC 2012).

Figure 1. Photo of Greenish-white Grasshopper.

Nymphs – There are 5 nymphal stages, known as instars, which can be individually identified based on size, structures present, and colour (see Pfadt 1996 for details). Instar 1 hatch from eggs at an approximate body length of 5.5 mm proceeding through subsequent stages until reaching Instar 5 with a range in size of 1.1 -1.82 cm (Pfadt 1996). All instars are green in colour with varying patterns of brown speckles. The nymphs live in the same habitats and consume the same food sources making it have the same host plant as adults (Pfadt 1996). In more southerly US populations the nymphal period from first hatching to adult lasts approximately 44-46 days (Alexander and Hilliard 1969, Pfadt 1996) but this time period is currently not known for Canadian populations.

Eggs – Eggs are laid in late summer just under the surface of the soil close to host White Sagebrush plants. With soil temperature building through the summer this timing allows laid eggs to reach a suffient development stage before they will overwinter in the ground in a state of diapause^{Footnote 4} (Fisher et al. 1996). The eggs are approximately 4 mm in length, tan in colour, and are laid in groups of 8 to 12 in egg pods that are oriented vertically in the soil (Pfadt 1996).

3.2 Species population and distribution

Global distribution

The Greenish-white Grasshopper is endemic to North America, being widely distributed within the Great Plains Region. It extends from southern Alberta, Saskatchewan and Manitoba, south into Montana, Wyoming, Colorado and into northern Texas, and east into North and South Dakota, Western Minnesota, Iowa, Nebraska, Kansas and Oklahoma (Figure 2; Brooks 1958, Pfadt 1996, Capinera et al. 2004, COSEWIC 2012). The species range is irregular and restricted within the broader distribution of the host food plant, White Sagebrush. The host plant has a range that extends further north and south (Northwest Territories through to Mexico), and east and west to both the Atlantic and Pacific coasts (Anderson 2005). Within its range, the Greenish-white Grasshopper is restricted in its distribution being found at lower elevations (e.g., generally <1800 m: Alexander and Hilliard 1969), and may be patchy as it is absent from areas where grasslands have been converted to annual crop agriculture (COSEWIC 2012).

Figure 2. Greenish-white Grasshopper global range (adapted from COSEWIC 2012, Pfadt 1996 and Vickery and Kevan 1985).

Canadian distribution and population

Like many prairie grassland species in Canada, populations of the Greenish-white Grasshopper are at the northern edge of their North American range. It is restricted to a small geographic area in the prairie provinces stretching across southern Alberta, southern Saskatchewan and southwestern Manitoba. Ecoregions represented in the distribution include the Mixed Grassland of Alberta and southwestern and south-central Saskatchewan, Moist Mixed Grassland of southeastern Saskatchewan and lastly into the Aspen Parkland of southwestern Manitoba. The estimated extent of occurrence^{Footnote 5} in Canada ranges from >43 000 to 46 000 km² and index of area of occupancy^{Footnote 6} ranges from 100 – 400 km² (COSEWIC 2012).

Historical records (prior to 1985) include 6 locations stretching from Onefour, AB; south of Coronach and near Big Muddy, SK, to Carberry, MB, primarily below 50°N clustering close to the border with the United States (Brooks 1958). Survey work from 1985 to 2009 found additional sites for the species around Medicine Hat, AB; in and around the Great Sand Hills, and in the west block of Grasslands National Park, SK (summarized in COSEWIC 2012). This work extended the range northward by nearly 100 km. The species was noted as being generally rare with low population sizes at some sites suggesting a decline in the number of sites and overall distribution from 2000 to 2007 (COSEWIC 2012). Directed searches for the species in southern Alberta and Saskatchwen from 2008 - 2010 by D. Johnson (University of Lethbridge) documented the species at 12 locations in southeastern Saskatchewan and southwestern Manitoba (Figure 3). In these surveys, the number of individuals identified ranged from 1 to >40 individuals per 10 m² at the sites. More recent surveys, since 2015, have reconfirmed occurrences of the species in the southern prairie provinces with many new occurrences at locations where the species had not been observed during earlier surveys and with highest abundance and frequency of occurrence noted in 2020 (D. Johnson pers. comm. 2020, R. Turnquist and K. Hecker, pers. comm. 2021, J. Tuckwell and S. Liccioli, pers. comm., 2021)

Collectively, existing records encompass 47 sites where Greenish-white Grasshoppers have been observed in Canada, including 33 from 2010-2021, eight from 1985-2009 and six historical sites prior to 1985 (Figure 3 and in Appendix A). In addition, recent information has emerged about several undocumented observations of the species since 2015 and especially in 2020 in southern Alberta (D. Johnson pers. comm. 2020).

Figure 3. Distribution of Greenish-white Grasshopper records in Alberta, Saskatchewan, and Manitoba based on records from 1920 until 2021. Note: at the scale shown some records overlap making them indistinguishable as distinct locations.

It is difficult to estimate the population size for a species that is naturally rare and poorly studied given the currently available data. The relative rarity of the species can be inferred from Johnson (1989) who failed to find Greenish-white Grasshopper among more than 11,000 grasshoppers collected near Taber, Alberta in habitat typically used by Greenish-white Grasshopper (Johnson 1989). Based on an extrapolation of numbers within designated areas, COSEWIC (2012) coarsely estimated that there are up to 1000 individuals on a typical 1000 ha site and that there would be over 100,000 grasshoppers within the currently known sites in Canada. However, there is a great deal of uncertainity associated with this estimate since relatively few sites have been surveyed and the field surveys that were conducted were not designed to estimate the species population size in Canada. Further complicating the estimation of population size is that temporal variability in numbers appears to be high, as individuals were encountered frequently in 2020 at locations in southern Alberta where they had not been observed in earlier years (D. Johnson pers. comm. 2020).

Surveys from 2008-2010 reconfirmed a northward decline in population densities where higher densities were observed at Canadian sites in close proximity to the United States border with the highest densities recorded at sites south of the border in North Dakota (COSEWIC 2012). At Canadian sites near the border, populations were confirmed at 12 of 15 sites that contained White Sagebrush although a zone along the Souris River in Saskatchewan had low grasshopper densities that had previously been high (COSEWIC 2012). Nevertheless, trends from these surveys show increases at some sites, such as south and west of Estevan, Saskatchewan where numbers observed exceed those recorded in the previous 20 years (COSEWIC 2012). Fluctuations in population size and density are natural in grasshopper populations owing to variation in weather conditions, availability and productivity of host plants, and pressures from disease and natural enemies such as predators and parasitoids (Branson 2005, Joern 2000, Laws and Joern 2012). Recent population increases in Greenish-white Grasshopper are believed to be closely tied to the growth of White Sagebrush, with large population increases observed in years when the food plant was abundant and experienced excellent growth (D. Johnson pers. comm. 2020, COSEWIC 2012).

3.3 Needs of the Greenish-white Grasshopper

General habitat requirements

The Greenish-white Grasshopper is a species of the Great Plains of North America where it is typically found in relatively undisturbed, dry mixed-grass prairie habitats such as managed pastures and grasslands (grazed but not improved rangelands and natural grasslands; COSEWIC 2012). In more southern areas of its range in the U.S., it can also be found in tallgrass and sandhills prairie habitats (Evans 1988, Joern 1983a). Within these general areas, the species is associated with habitats where primary host White Sagebrush plants occur. This can include sites such as native prairie, grazed rangelands and livestock pastures, uncultivated areas along roadsides, fencelines, streams, shelterbelts, and some disturbed sites (COSEWIC 2012, Whipple et al. 2012). Greenish-white Grasshopper is not found at every site where the primary host plant occurs however; it can occur at a small proportion of the sites with host plants or also be absent from areas where abundance of host plants is quite high (COSEWIC 2012). Since the species overwinters as eggs laid just under the surface of the soil, suitable soils with the appropriate composition, texture and generally favourable soil conditions (e.g., moisture, topographic position) may also be important (Criddle 1935).

Host plant specificity

In contrast to the large majority of grasshoppers that typically feed on a wide variety of plant species, the Greenish-white Grasshopper is a specialist species feeding primarily on White Sagebrush (Knutson 1982, Joern 1985). This plant is not eaten to any great extent by other grasshopper species since it has physical and/or chemical defenses that make it less palatable. These include a dense covering of largely indigestible small hairs on the leaves (trichomes) that the Greenish-white Grasshopper is capable of ingesting and others are not (Smith and Kreitner 1983, Blust and Hopkins 1987a). The plant also produces volatile compounds such as terpenoids that deter other grasshopper species and/or attract the Greenish-white Grasshopper to it (Blust and Hopkins 1987b). An ability to use a food plant that other grasshoppers do not may mean competition for food resources is lowered for Greenish-white Grasshopper. Other secondary plant foods occasionaly used by the species in other parts of its range include other sage plants like Pasture Sage (A. frigida) and Silver Sagebrush (A. cana), forbs such as Purple Locoweed (Oxytropis lambertii) and Western Wallflower (Erysimum asperum), and grasses such as Blue grama (Bouteloua gracilis), Buffalograss (Bouteloua dactyloides) and needle-and-thread grass (Hesperostipa comata) (Joern 1985, Chapman 1990, Pfadt 1996). It is important to note that these other plants are consumed in much smaller amounts compared to White Sagebrush.

White Sagebrush is used as food for all life stages of the Greenish-white Grasshopper from hatched nymphs through to adults making it a key food plant for the species. Plants are a silvery-green colour that appear as greenish-white from a distance owing to the covering of fine trichomes on stems and leaves (USDA 2017). It typically reaches a size of 20 to 50 cm in height and it flowers from August to September with yellow-ish flowers (USDA 2017). The species is native to the prairies and it responds fairly well to disturbances such as fire, grazing and occasional flooding depending on the intensity and timing of these activities (Archibold et al. 2003, Anderson 2005). Although widely distributed, White Sagebrush is often a minor component of plant communities owing to climatic factors and specific site disturbance histories that make its distribution on the landscape quite patchy (Smith and Grodowitz 1987, Anderson 2005, Adams et al. 2013, COSEWIC 2012).

In addition to feeding on White Sagebrush, Greenish-white Grasshopper also lays eggs in the top layer of the soil near host food plants (Criddle 1935, Pfadt 1996). This facilitates newly hatched nymphs being in proximity to the food plant upon hatching for rapid development which is beneficial for a late-hatching species. The species shows a general low mobility compared to other grasshoppers and shows strong host-plant fidelity (Joern 1983b, Pfadt 1996). In a study in Kansas, daily movements were found to be quite low (averaging around 106 cm and at maximum 3 m) with individuals remaining in close proximity to host plants, if not the same plant for multiple days (Smith and Grodowitz 1987). In that same study, dispersal among host plant patches was also exceptionally low with marked individuals never being recorded moving among study plant patches separated by a distance of only 8 m. Movements in general may be low if a sufficient number of high quality host food plants are available in a local patch area to meet the needs of grasshoppers. These movements may be larger in areas or years when food plant resources are less abundant and available. The finding of some females with long wings may suggest the species can make larger movements from time to time although this is not known (COSEWIC 2012). The species is not currently known to migrate (COSEWIC 2012).

With the colour of Greenish-white Grasshopper closely matching that of the host plant, White Sagebrush also likely provides camouflage to the species to minimize predation (Knutson 1982, Smith and Grodowitz 1987). When disturbed and flushed, they will jump off a plant but almost immediately jump back to another nearby host plant, rather than remain on the ground (Pfadt 1996). This supports the idea of the grasshoppers using the plants for shelter from predators. Thus, Greenish-white Grasshoppers carry out multiple daily activities on the plants including taking advantage of various opportunities for optimizing their thermal conditions. Activities include stretching out their legs to better expose their abdomen to the sun’s rays for warming (basking), retreating to shaded areas of plants during hot periods, or in taking shelter overnight (Pfadt 1996, Blust and Hopkins 1990).

3.4 Limiting factors^{Footnote 7}

Reliance on a single host plant

Greenish-white Grasshopper relies heavily on one species of plant for multiple aspects of its life history including feeding by immature nymphs during development, feeding by adults, and to some extent, for breeding and overwintering. Thus, the species almost continually occupies or is in close contact with host White Sagebrush plants where the distribution and abundance of plants at a site will impact these same parameters of Greenish-white Grasshopper populations (Pfadt 1996). Any reductions in the growth, density or distribution of the host plant could result in periodic reductions in the abundance of the species (COSEWIC 2012).

Limited dispersal capability

As it is currently understood, the species has a low dispersal ability as it is small in size, generally flightless, and has low mobility since individuals make limited movements (Smith and Grodowitz 1987). The re-establishment of historical and now lost populations, and rescue effects from the movement of individuals from more abundant populations (e.g., from those in the United States) may be limited due to this low dispersal ability. Furthermore, dispersal from fragmented or destroyed habitat to colonize new habitat is also likely limited. Combined with other other traits such as being a late-hatching species, and having a high reliance on one host plant means that recovery from low population abundances or a reduced distribution could take longer (COSEWIC 2012).

Natural predators and parasites

In addition to factors such as weather and host plant availability and quality, grasshopper populations are also influenced by pressures from competition with other species, disease, predators and parasitoids (Joern 2000, Branson 2005, Laws and Joern 2012). Predation by birds has been shown to contribute to regulation of grasshopper populations (Bock et al. 1992, Branson 2005). However, the effects can be complex and variable across locations as they may depend on the local site grasshopper community and availability of food resources (Belovsky and Joern 1995). It is suspected that Greenish-white Grasshopper is subject to bird predation although this has not yet been documented for the species (COSEWIC 2012).

Other known predators of grasshoppers include spiders but similar to bird predation, the effects can be context-dependent (Oedekoven and Joern 2000, Laws and Joern 2015). Still other known grasshopper predators include beetles, crickets and bee flies that feed on grasshopper eggs (Joern and Gaines 1990). Parasitoid^{Footnote 8} flies have been shown to prey on Greenish-white Grasshopper which, in turn, impacts the reproductive output of individuals (Laws and Joern 2012). Other parasites like mites and nematodes may also infect and impact the species such as those found in other grasshopper species (Branson 2003, Laws 2009). Since the impacts of these biotic interactions are variable, dependant on habitat and resource availability, and have not generally been looked at collectively for the species, these interactions and effects are not known in how they impact Greenish-white Grasshopper population dynamics.

Thermal and moisture sensitivity

It is thought that Greenish-white Grasshopper is likely not resistant to conditions of prolonged extreme heat and drought because it has a delicate integument^{Footnote 9}, and the abdomen is not protected by heavy forewings as is found in other prairie grasshoppers (COSEWIC 2012). These physical characteristics may mean that the species has a high susceptibility to drying out, heat stress and overheating, which in turn may limit the species’ survival rate; however, this has not been directly investigated.

4. Threats

4.1 Threat assessment

The Greenish-white Grasshopper threat assessment is based on the IUCN-CMP (World Conservation Union–Conservation Measures Partnership) unified threats classification system. Threats are defined as the proximate activities or processes that have caused, are causing, or may cause in the future the destruction, degradation, and/or impairment of the entity being assessed (population, species, community, or ecosystem) in the area of interest (global, national, or subnational). Limiting factors are not considered during this assessment process. For purposes of threat assessment, only present and future threats are considered. Historical threats, indirect or cumulative effects of the threats, or any other relevant information that would help understand the nature of the threats are presented in the Description of Threats section.

^a Impact – The degree to which a species is observed, inferred, or suspected to be directly or indirectly threatened in the area of interest. The impact of each threat is based on Severity and Scope rating and considers only present and future threats. Threat impact reflects a reduction of a species population or decline/degradation of the area of an ecosystem. The median rate of population reduction or area decline for each combination of scope and severity corresponds to the following classes of threat impact: Very High (75% declines), High (40%), Medium (15%), and Low (3%). Unknown: used when impact cannot be determined (e.g., if values for either scope or severity are unknown); Not Calculated: impact not calculated as threat is outside the assessment timeframe (e.g., timing is insignificant/negligible or low as threat is only considered to be in the past); Negligible: when scope or severity is negligible; Not a Threat: when severity is scored as neutral or potential benefit.

^b Scope – Proportion of the species that can reasonably be expected to be affected by the threat within 10 years. Usually measured as a proportion of the species’ population in the area of interest. (Pervasive = 71–100%; Large = 31–70%; Restricted = 11–30%; Small = 1–10%; Negligible < 1%).

^c Severity – Within the scope, the level of damage to the species from the threat that can reasonably be expected to be affected by the threat within a 10-year or three-generation timeframe. Usually measured as the degree of reduction of the species’ population. (Extreme = 71–100%; Serious = 31–70%; Moderate = 11–30%; Slight = 1–10%; Negligible < 1%; Neutral or Potential Benefit ≥ 0%).

^d Timing – High = continuing; Moderate = only in the future (could happen in the short term [< 10 years or 3 generations]) or now suspended (could come back in the short term); Low = only in the future (could happen in the long term) or now suspended (could come back in the long term); Insignificant/Negligible = only in the past and unlikely to return, or no direct effect but limiting.

4.2 Description of threats

The threats that impact Greenish-white Grasshopper are poorly understood as the specific information of these threats to the species is generally incomplete (COSEWIC 2012). With the species relying on primarily one main host plant, ultimately any threats to the host White Sagebrush plants are threats to Greenish-white Grasshopper (Hall et al. 2011). The loss of host plants or a reduction in the quality of host plants as habitat could occur as a result of threats acting together or on their own. This could occur from changes to the natural disturbance regime such as changes to grazing or fire regimes, landscape hydrology and climate. Direct habitat loss, degradation or fragmentation can also occur from multiple threats such as enhancing forage production in pastures, conversion to cultivated crops, herbicide and pesticide use, road construction or maintenance, and oil and gas drilling. The identified threats to Greenish-white Grasshopper are discussed in depth below.

IUCN-CMP threat 2. Agriculture and aquaculture (low)

Threat 2.1 Annual and perennial non-timber crops

The historical conversion of native prairie habitat to cultivated crops likely contributed to an overall loss and fragmentation of Greenish-white Grasshopper habitat. Conversion of current native grasslands and rangeland habitats (where host plants occur) to planted areas for cereal and forage crops remains an ongoing threat to the species. This is due to factors such as increased prices for specific crops and advancements in new agricultural technologies and practices (Wright and Wimberly 2013, Lark et al. 2015). When these factors reduce production costs and drive demand for these crops and land for their cultivation, this may make areas previously less suitable for cultivation (e.g., rangelands and native grasslands) attractive as new targets for planted crops. Those grassland habitats that contain host plants for Greenish-White Grasshopper that are converted to cultivated crops would represent loss and potentially fragmentation of key habitat for the species.

Threat 2.3 Livestock farming and ranching

The host plant of Greenish-white Grasshopper has a generally low forage value for livestock and is thus not a highly desired plant for grazing livestock (Tannas 2004, Anderson 2005) although is often a minor component of the plant community of grazed pastures (COSEWIC 2012). Pastures and ranges are sometimes improved by seeding or overseeding with desired pasture plants to improve yields or extend the seasonal timing of productivity. These improved pastures are sometimes known as tame pastures. If these planted species are strong plant competitors, they can outcompete the host plant. Any reductions in host plant population or distribution would then negatively impact Greenish-white Grasshopper.

Before the introduction of cattle, the grasslands of Canada were primarily grazed by herbivores such as Bison (Bison bison), Pronghorn (Antilocapra americana) and Elk (Cervus Canadensis) such that Greenish-white Grasshopper evolved in a landscape subject to grazing that occurred at variable intensities, locations and frequencies (Anderson 2006, Shorthouse and Larson 2010a). Cattle grazing has a long history on pastures and rangelands that occur within the range of Greenish-white Grasshopper dating back to European settlement. Areas were subjected to varying grazing intensities managed at a localized level depending on land tenure, local site environmental conditions (e.g., weather, topography), and practices of range management at the time (Wang et al. 2014). Grazing has been shown to have mixed effects on White Sagebrush where in one study it reduced plant density (Brand and Goetz 1978) but in others there was increased plant growth (Anderson 2005). This suggests that some level of grazing is tolerated by the plant but heavy and intensive grazing (overgrazing) may limit the plants a bility to grow and recover such that other plants takeover resulting in the elimination of host plants (COSEWIC 2012). Specific grazing conditions (e.g., cattle stocking rates^{Footnote 10}, rest periods etc.) that are tolerated or are beneficial to White Sagebrush plants are not currently known.

IUCN-CMP threat 3. Energy production and mining (low)

Threat 3.1 Oil and gas drilling

The construction of oil and gas wells could destroy or fragment White Sagebrush habitat for Greenish-white Grasshopper. These impacts would depend on the size, number and extent (e.g., density) of disturbed areas in relation to distribution and abundance of the host plants on the landscape. Impacts from from oil and gas drilling are expected to continue in the future and may increase depending on the economic conditions that drive energy demand and exploration. There are other impacts from oil and gas activities and these are covered under their respective threat categories (pipelines, roads and invasive non-native species).

IUCN-CMP threat 4. Transportation and service corridors (low)

Threat 4.1 Road and railroads

The construction of roads can destroy, degrade or fragment habitat containing White Sagebrush host plants that are essential for Greenish-White Grasshopper survival. Roads can result in direct loss of habitat and create large linear disturbances of degraded habitat from introducted plant species that out-complete White Sagebrush (see threat 8.1; Nasen et al. 2011, Manier et al. 2014). These impacts would act to to isolate local Greenish-white Grasshopper populations since it is a largely flightless species that has limited dispersal ability.

Roads and associated road allowance maintenance can result in mortality to individuals and some occurrence records for the species are from known from road allowances. Mechanized mowing for weed control and harvest (e.g., haying) is known to impact grasshoppers by causing direct mortality of individuals or result in their displacement from habitats as they move to escape the disturbance (Gardiner and Hill 2006, Humbert et al. 2012). Displacement could result in mortality for Greenish-white Grasshopper if they are unable to find new host plants. This would be of concern in situations where road allowances containing host plants are surrounded by cultivated areas and thus represent isolated and fragmented habitat islands for Greenish-white Grasshoppers. Chemical control of weeds on road allowances are discussed in threat 9.3. The threat of road construction and maintenance is expected to continue in future years.

IUCN-CMP threat 7. Natural system modifications (unknown)

Threat 7.1 Fire and fire suppression

Insects living on the prairie such as Greenish-white Grasshopper, evolved with disturbances such as grazing, and periodic drought and fire that impacted the distribution and abundance of plant resources these insects require (Hall et al. 2011). Land management practices since European settlement have resulted in the reduction in frequency and extent of fires on the prairie from reductions in grass biomass fuels (from introduced livestock grazing) and fire suppression (Brockway et al. 2002). Host plants of Greenish-white Grasshopper have shown a mixed response to prescribed fires. In studies in Alberta and Saskatchwan, density and canopy coverage of White Sagebrush was shown to increase post-burn (Bailey and Anderson 1978, Archibold et al. 2003). However, in other studies little or negative-effects of fire have been shown depending on the burn season and interaction of other disturbance histories at the sites (e.g., grazing; reviewed in Anderson 2005). The specific effects of prescribed burns and long-term fire suppression on Greenish-white Grasshopper subpopulations are not currently known.

Threat 7.2 Dams and water management/use

The host plant of Greenish-white Grasshopper is frequently associated with moist and mesic sites such as streambanks, floodplains, roadsides and valley bottoms (Coupland 1950, Coxson and Looney 1986). The natural water flow at a site can be altered by the construction and operation of man-made dams, dugouts, ditches and resevoirs for livestock watering, irrigation of cropland, and wetland drainage. These structures divert water and can reduce the magnitude and/or frequency of flood events and instream flow such that important natural disturbances like overflow and sedimentation are interrupted (McNeil et al. 2004). This is particularily problematic during periods of drought. Since White Sagebrush is associated with mesic sites that may be subject to periodic flooding, changes to the natural hydrology of these sites from these man-made structures may alter plant productivity or result in elimination of plant subpopulations and may negatively impact Greenish-white Grasshopper populations.

IUCN-CMP threat 9. Pollution (low)

Threat 9.3 Agricultural and forestry effluents

A small proportion (approximately 12%) of the more than 85 species of grasshoppers found in the Canadian prairies are considered to be pests (at certain times) because they damage crop or forage plants of economic importance when their populations are large (Calpas and Johnson 2003). Greenish-white Grasshopper is not considered a pest species since it does not feed on plants of high economic value and occurs in low numbers (COSEWIC 2012). Nevertheless, the use of broad spectrum insecticides to control grasshoppers in pastureland and other types of land where Greenish-white Grasshopper habitat exists would likely kill individual Greenish-white Grasshoppers and could result in the loss of small local populations (COSEWIC 2012). Although several insecticides are approved for use to control grasshoppers in pastures (e.g., Government of Saskatchewan 2021), the extent of their use in such habitat where Greenish-white Grasshopper is most often found, is unknown, but is believed by several experts to be low (J. Kotlar and R. Turnquist, ECCC, 2021; S. Hartley and J. Tansey, Government of Saskatchewan, pers. comm, 2021). The contention that use of insecticides for grasshopper control in pastures is low is supported by an economic analysis indicating that the cost of applying insecticides to pastures to control grasshoppers likely exceeds the benefit derived from that application unless the cost is subsidized by the government (Shewchuk and Kerr 1993), as was the case during the 1980’s but is no longer the case today. Furthermore, it is unknown whether Greenish-white Grasshopper would be affected by the use of bran-bait insecticides which are labelled for control of grasshoppers in pastures and rangelands, but which may not attract Greenish-white Grasshopper given the species’ fidelity to White Sagebrush. Negative effects could also occur due to drift from pesticide application in cropland areas that lie adjacent to Greenish-white Grasshopper habitat, although the amount of drift would likely decline steepily within a short distance from the edge of the crop (Bird et al. 1996).

In controlling weedy or invasive plant species on linear disturbances (road allowances, pipelines, transmission lines) or managed tame pastures, the use of broad-spectrum herbicides, such as glyphosate, to control undesirable plants could reduce host plant productivity or eliminate host plant populations such that Greenish-white Grasshopper populations are in turn negatively impacted (COSEWIC 2012).

IUCN-CMP threat 11. Climate change and severe weather (unknown)

Threat 11.2 Drought

An increased frequency of dry periods could decrease populations of Greenish-white Grasshopper because the species does not seem to have physical characteristics that would enable them to deal well with such conditions (COSEWIC 2012). Climate change scenarios for the prairie provinces project greater precipitation, and possibly warmer weather, but this precipitation may fall outside of the dry summer season (Sauchyn and Kulshreshtha 2008). Further, warmer conditions may impact winter hydrological inputs (e.g., negative effects on snowpack and glaciers) and evaporation rates in spring and summer such that drought conditions would increase in frequency or severity (Sauchyn and Kulshreshtha 2008, Schindler and Donahue 2006). While the potential of this threat specifically to Greenish-white Grasshopper is currently not known, it is possible that low winter snowpack and sudden cold snaps could have a deleterious impact on overwinter egg survival (J. Tansey pers. comm. 2021).

5. Management objective

The management objective for Greenish-white Grasshopper is to maintain the distribution of the species, based on records from 1985 until 2021, in Alberta, Saskatchewan and Manitoba, as well as any additional populations that are discovered or rediscovered in the future.

With information generally lacking on the overall distribution, local population abundances and trends for the species in Canada, it is currently not feasible to develop a quantitative management objective. Moreover, as its Canadian distribution represents the northern edge of its global range and as it appears to occur patchily across its Canadian distribution and to experience wide and unpredictable population fluctuations over time, a distribution-based management objective may be the most reasonable approach for the Greenish-white Grasshopper. This objective will be achieved by reducing or eliminating threats to the species and its habitat.

6. Broad strategies and conservation measures

6.1 Actions already completed or currently underway

Relatively little work has been done in advancing our understanding of the biology and ecology of Greenish-white Grasshopper in Canada. Actions specific to monitoring and/or conserving the species, that have been completed or are currently underway include:

Actions completed

The BIObus project of the Centre for Biodiversity Genomics at the University of Guelph samples arthropod diversity across National Parks in Canada. Surveys for grassland arthropods were carried out in Grasslands National Park in Saskatchewan. Specimens were collected and submitted for genetic analysis (i.e., DNA sequencing to obtain DNA barcodes ) that included the collection, sequencing and identification of a Greenish-white Grasshopper in the summer of 2008.

In preparation for the COSEWIC status report, targeted surveys for the species were carried out by Dr. Dan Johnson (University of Lethbridge) along road-side transects in Alberta, Saskatchewan, and Manitoba (2008 -2010).

Actions current/ongoing

Monitoring for Greenish-white Grasshopper continues to be carried out by Dr. Dan Johnson (University of Lethbridge) in Alberta and Saskatchewan (2011-current).

A photo identification guide of prairie grasshoppers for non-specialists is being developed by Dr. Dan Johnson (University of Lethbridge). It will update an earlier one that he published in 2008 by Dr. Johnson.

Under the umbrella of NatureServe, the Manitoba Conservation Data Centre and Sasktachewan Conservation Data Centre track and store information of Greenish-white Grasshopper occurrences in their respective provinces.

Data collection by the general public on occurrences and distribution of the species in North America through iNaturalist^{Footnote 11} and the Global Biodiversity Information Facility (GBIF)^{Footnote 12} databases.

6.2 Broad strategies

To achieve the management objective, conservation measures to be carried out are organized under four broad strategies:

• inventory and monitoring
• research to address knowledge gaps of the species and its habitat
• communication, collaboration and engagement
• habitat management and conservation

6.3 Conservation measures

^a “Priority” reflects the degree to which the measure contributes directly to the conservation of the species or is an essential precursor to a measure that contributes to the conservation of the species. High priority measures are considered those most likely to have an immediate and/or direct influence on attaining the management objective for the species. Medium priority measures may have a less immediate or less direct influence on reaching the management objective, but are still important for the management of the population. Low priority conservation measures will likely have an indirect or gradual influence on reaching the management objective, but are considered important contributions to the knowledge base and/or public involvement and acceptance of the species.

6.4 Narrative to support conservation measures and implementation schedule

Broad strategy – inventory and monitoring

Few targeted surveys have been carried out for Greenish-white Grasshopper in Prairie Canada where these surveys assessed presence/no evidence of presence and were not able to estimate population size. Further, owing to the large area to be surveyed across the species range in three provinces, these previous surveys have been largely opportunistic or highly targeted in nature where only small areas at a time could be surveyed and they have not been revisited. The use of existing recent survey data in conjunction with new surveys could be explored for developing a habitat suitability model to help identify priority search areas to target survey efforts. The implementation of a standardized methodology for surveys throughout the species range is needed to locate new populations, re-confirm historical populations and tease out important habitat characteristics for the species. Given the large area to be surveyed, the use of standardized methods will facilitate multiple groups or organizations to collaborate in survey efforts where data can be combined across surveys in a comprehensive manner. Standardized methods will enable a monitoring program to be developed and implemented to estimate population sizes, track population dynamics and explore these interactions with habitat conditions over time. Citizen science initatives such as iNaturalist (www.inaturalist.org) have significant potential to yield new data about occurrences of the species and should be supported.

Broad strategy – research to address knowledge gaps of the species and its habitat

There are many knowledge gaps on several aspects of the species’ life cycle characteristics, ecology, and threat impacts that require research. Basic aspects of the timing and duration of the various life stages (i.e., overwintering eggs, nymphs and adults) are poorly characterized in Canada. Since populations in Canada are at the northern periphery of the species range these may be different from more southern populations in the US. Critical aspects of the species ecology such as dispersal, recruitment, survival, and genetic connectivity of populations are lacking. These parameters and characteristics are important for understanding basic population dynamics (e.g., size, status and trends) of the species. They are also important for understanding the adaptability of the species to help determine if there are periods of sensitivity. Collectively, these are important components of understanding how and when the identified threats specifically impact the species. In general, the impacts of the identified threats are poorly understood and research on these is needed. For example, specific grazing conditions (e.g., cattle stocking rates, rest periods etc.) or natural disturbance regimes (e.g., fire, floods) that are tolerated, beneficial or harmful to White Sagebrush plants and thus Greenish-white Grasshopper are not currently known. Lastly, research that links aspects of the species biology and ecology to the effects of a changing climate are also needed.

Broad strategy – communication, collaboration and engagement

The role of grasshoppers as important components of biodiversity in grassland ecosystems is not often considered or is underappreciated. Their roles include being being a key food source for organisms such as grassland songbirds (Martin et al., 2000) and in contributing to nutrient cycling in grasslands via grazing as insect herbivores (Belovsky 2000). Often all prairie grasshoppers are grouped together and viewed uniformly as pest species that exhibit periodically damaging outbreaks to economically important crops. As a result, prescriptive broad level grasshopper controls (e.g., spraying with pesticides) may be applied regardless of what species they are and what plants they consume. Increasing education and awareness of non-pest grasshopper species and their ecological value and roles, including Greenish-white Grasshopper, is recommended through various communications (e.g., grasshopper identification materials, species at risk guides). Beneficial management practices (e.g., for mowing and grazing regimes to retain and maintain high quality host plants; and integrated pest management) should be developed and implemented. This can be accomplished through collaborations with species groups experts such as academic researchers, and research scientists with Agriculture and Agri-Food Canada or provincial agriculture departments. Further, many existing conservation organizations have programs that actively engage land owners and managers already and would be valuable collaborators for these efforts. Examples include MULTISAR and Operation Grassland Community in Alberta, SODCAP Inc. in Saskatchewan, and the Manitoba Habitat Heritage Corporation in Manitoba.

Broad strategy – habitat management and conservation

Key management and conservation of habitat for Greenish-white Grasshopper will occur from voluntary measures such as beneficial management practices for managing pastures and grasslands, and from stewardship agreements for land management and protection. Land use planning at multiple levels (municipal, provincial, federal) that incorporates the retention and protection of important habitat features (e.g., native grasslands and managed pastures) will assist in the long term conservation and persistence of Greenish-white Grasshopper habitat for current and future populations.

7. Measuring progress

The performance indicator presented below provides a way to measure progress towards achieving the management objectives and monitoring the implementation of the management plan.

• the populations of Greenish-white Grasshopper found from 1985 until 2021 in Alberta, Saskatchewan, and Manitoba, as well as any additional populations newly located or rediscovered in the future, are maintained or increased by 2031

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Personnal communication

James Tansey – Government of Saskatchewan

Appendix A: Summary of Greenish-white Grasshopper records in Canada

^a Data source abbreviations as follows: AAFC – Agriculture and Agri-Foods Canada; CNC - Canadian National Collection of Insects, Arachnids, and Nematodes; COSEWIC – Committee on the Status of Endangered Wildlife in Canada (2012); UGCBG – University of Guelph, Centre for Biodiversity Genomics; D. Johnson – D. Johnson, University of Lethbridge, AB; inaturalist.org – www.inaturalist.org; JBWM – JB Wallis/RE Roughley Museum at University of Manitoba; LEM – Lyman Entomological Museum, McGill University; Vickery and Kevan - Vickery, V.R., and D.K. McE. Kevan. 1985. The Grasshoppers, crickets and related insects of Canada and adjacent regions. Agriculture Canada, Research Branch, Publication 1777, Ottawa.

Appendix B: 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 13}. 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 14} (FSDS) goals and targets.

Conservation planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that implementation of management plans 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 management plan itself, but are also summarized below in this statement.

This management plan will benefit the environment by promoting the conservation of the Greenish-white Grasshopper. The potential for the plan to inadvertently lead to adverse effects on other species was considered. The SEA concluded that this plan will benefit the environment and will not entail any significant adverse effects. The most significant effect that conservation and habitat management for Greenish-white Grasshopper will have on other species will be the protection of grassland habitats.

Many other species use native grassland habitats during all or portions of their life cycles in locations that overlap to varying degrees with the range of Greenish-white Grasshopper. This includes several federal species at risk: Dakota Skipper (Hesperia dacotae), Monarch (Danaus plexippus), Morman Metalmark (Apodemia mormo), McCown’s Longspur (Rhynchophanes mccownii), Baird’s Sparrow (Ammodramus bairdii), Chestnut-collared Longspur (Calcarius ornatus), Long-billed Curlew (Numenius americanus), Sprague’s Pipit (Anthus spragueii), Sage Thrasher (Oreoscoptes montanus), Ferruginous Hawk (Buteo regalis), Greater Sage-grouse (Centrocercus urophasianus), American Badger taxus subspecies (Taxidea taxus taxus), Swift Fox (Vulpes velox) and Buffalograss (Bouteloua dactyloides). Conservation and management efforts that are designed to conserve and restore native prairie or create grassland habitats could benefit these species. To avoid potential negative effects on other species at risk, the ecological risks to other species should be evaluated prior to the implementation of habitat management actions for Greenish-white Grasshopper. For more information on how Greenish-white Grasshopper interact with other species and the ecosystem, refer to the following sections of this document: Species Description, Needs of the Greenish-white Grasshopper, Threats and Conservation Measures.