Short-fruited Rush (Juncus brachycarpus): COSEWIC assessment and status report 2024

Official title: COSEWIC assessment and status report on the Short-fruited Rush (Juncus brachycarpus) in Canada

Committee on the status of Endangered Wildlife in Canada (COSEWIC)

Endangered 2024

COSEWIC assessment summary

Assessment summary – November 2024

Common name: Short-fruited Rush

Scientific name: Juncus brachycarpus

Status: Endangered

Reason for designation: This large perennial rush has a very restricted range in Canada where it is known from remnant patches of tallgrass prairie in Windsor, Ontario. The Canadian population has declined to 130 flowering stems at two extant sites. Historically the plant has lost habitat to agriculture, housing, and transportation infrastructure, and continues to be threatened with habitat degradation due to invasive plants and fire suppression.

Occurrence: Ontario

Status history: Designated Endangered in November 2024.

COSEWIC executive summary

Short-fruited Rush

Juncus brachycarpus

Wildlife species description and significance

Short-fruited Rush (Juncus brachycarpus) is a comparatively large perennial rush with a highly localized distribution in Canada. The inflorescence is a panicle of 1 to 10 densely spherical heads, with 30 to 100 flowers per head. The fertilized flowers develop into brown capsules, which do not exceed the length of the tepals. The absence of a tail-like appendage on the seeds separates this species from some others in the genus.

The species is part of a remnant assemblage of vascular plants that occur in tallgrass prairie, a formerly more extensive ecosystem in southern Ontario that has significantly declined as a result of agricultural and urban development.

Aboriginal (Indigenous) knowledge

Aboriginal Traditional Knowledge (ATK) is relationship-based. It involves information on ecological relationships between humans and their environment, including characteristics of species, habitats, and locations. Laws and protocols for human relationships with the environment are passed on through teachings, stories, and Indigenous languages, and can be based on long-term observations. All species are significant and are interconnected and interrelated. There is no species-specific ATK in the report.

Distribution

Short-fruited Rush occurs throughout much of the eastern United States but, in Canada, is found only in Windsor, Ontario. The species requires specific habitat and has only been identified in remnant tallgrass prairie habitats, which once dominated the region but have been reduced to a fraction of their previous extent. Its current distribution is in small remnant patches of suitable habitat, with the largest patch being the Ojibway Prairie Complex in the City of Windsor.

Habitat

In Canada, Short-fruited Rush is a habitat specialist, and is only found in wet-mesic to mesic prairie habitat.

Across the U.S., Short-fruited Rush is reported to occur in a variety of open habitat types, including lakeplain wet prairies and seasonally inundated sandy depressions, where it is often found in association with other rare species.

Biology

Short-fruited Rush is a perennial rush that reproduces asexually through rhizomes, as well as sexually by seeds. The seeds are contained within a capsule-like fruit, which often persists through the winter.

Population sizes and trends

Fieldwork undertaken in 2022 resulted in 154 individuals counted at three sites. One site (Northway) is the result of sod transplanted from a natural prairie as part of a restoration project and, following COSEWIC guidelines, is not included in the quantitative criteria in this assessment. Currently, 130 individuals are known in the other two extant sites. Four previously reported sites could not be relocated and are considered extirpated. The abundance of Short-fruited Rush prior to European contact or the large-scale conversion of tallgrass prairie and savannah habitats to agricultural lands across southern Ontario is unknown. Most verified reports of this species in Canada do not include species counts beyond a rough estimate. There are no historical population estimates for Short-fruited Rush in Canada.

Threats

Invasive species are considered to be a serious and plausible threat to the persistence of Short-fruited Rush in Canada. Several sites where the species was known to occur have been lost through encroachment of European Common Reed. Autumn Olive is also increasing in the area and is believed to be negatively altering the habitat of this species.

Fire suppression is also a major threat, because the sites are surrounded by suburban development. Prescribed burns have been carried out at all the extant sites and help to maintain the integrity of the tallgrass ecosystem, but the nearby housing in the area puts limitations on their use. Thus, continuous human intervention may be required to support the existing habitat.

Recreational activities are considered a low-impact threat that persists at some of the sites, particularly potential threats from ATV use and impacts due to trampling.

Protection, status, and recovery activities

The status of Short-fruited Rush has not previously been assessed by the Committee on the Status of Species at Risk in Ontario (COSSARO). The species has a NatureServe conservation status rank of N1 (Critically Imperilled) in Canada and S1 (Critically Imperilled) in Ontario. The species is ranked S1 in New York, New Jersey, Pennsylvania, and West Virginia; S1S2 (Critically Imperilled to Imperilled) in Michigan where it is afforded some protection; and S2? (Imperilled?) in North Carolina.

The Ojibway Prairie provincial park is designated as a nature reserve class park, under the official name Ojibway Prairie Provincial Nature Reserve, pursuant to the Provincial Parks and Conservation Reserves Act (2006) and will continue to provide habitat for this species. The other sites occur on public lands administered by the Ontario Ministry of Transportation.

Technical summary

Juncus brachycarpus

Short-fruited Rush

Jonc à fruits courts

Range of occurrence in Canada: Ontario

Demographic information

Generation time (usually average age of parents in the population)

Approximately 3 to 10 years.

Based on data for other perennial Juncus species

Is there an [observed, estimated, inferred, or projected] continuing decline in number of mature individuals?

Yes

Observed losses of four sites and inferred decline due to ongoing threats

[Observed, estimated, or projected] percent of continuing decline in total number of mature individuals within 3 years [or 1 generation; whichever is longer up to a maximum of 100 years]

Unknown

Insufficient data to infer % change over this time scale

[Observed, estimated, or projected] percent of continuing decline in total number of mature individuals within 5 years [or 2 generations; whichever is longer up to a maximum of 100 years]

Unknown

Insufficient data to infer % change over this time scale

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last 10 years [or 3 generations; whichever is longer]

Unknown

Insufficient data to infer % change over this time scale

[Projected, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations, up to a maximum of 100 years]

Unknown

Insufficient data to infer % change over this time scale

[Observed, estimated, inferred, projected, or suspected] percent [reduction or increase] in total number of mature individuals over any period of 10 years [or 3 generations; whichever is longer, up to a maximum of 100 years], including both the past and future (up to a maximum of 100 years in future)

Unknown

Insufficient data to infer % change over this time scale

Are the causes of the decline clearly reversible?

Possibly

Management of invasive species and controlled burning may reverse decline.

Are the causes of the decline clearly understood?

Yes

Current declines in microhabitat availability in protected sites are due to invasive species.

Have the causes of the decline clearly ceased?

No

Conversion of suitable habitat to agriculture has ceased, but loss from infrastructure development (roads and utilities) continues. Invasive species and fire suppression continue to be a threat to the species.

Are there extreme fluctuations in number of mature individuals

Unlikely

Insufficient data exist to make an estimate of fluctuations in number of mature individuals; however, it is unlikely to be extreme because the species is a perennial plant in a managed landscape.

Extent and occupancy information

Estimated extent of occurrence (EOO)

4 km²

The calculated EOO is 0.94 km² (2022). Because the EOO is smaller than the Index of area of occupancy (IAO), the larger IAO value is used.

Index of area of occupancy (IAO), reported as 2x2 km grid value

4 km²

Is the population “severely fragmented”, that is, is >50% of individuals or >50% of the total area “occupied” (as a proxy for number of individuals) in habitat patches that are both (a) smaller than required to support a viable subpopulation, and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse?

1. Unknown
2. Unknown

The population is small, fragmented, and isolated; however, the amount of habitat required to support a viable population is unknown.

Number of “locations” (use plausible range to reflect uncertainty if appropriate)

2

As of 2022, there were two known locations based on land ownership, which reflects the potential for managing threats in locations.

Is there an [observed, inferred, or projected] continuing decline in extent of occurrence?

Yes. Observed.

There is an observed decline in the extent of occurrence. Four of the previously reported sites in the Windsor area are now extirpated. The EOO of 0.94 km² represents an 82% decline from the historical EOO of 4.65 km², based on data from 1996 to 2022. Habitat decline is continuing due to the spread of invasive plants.

Is there an [observed, inferred, or projected] continuing decline in area of occupancy?

Yes

There is an inferred decline in the area of occupancy based on the historical loss that is believed to be continuing.

Is there an [observed, inferred, or projected] continuing decline in number of subpopulations?

No.

Losses are occurring in sites within a single subpopulation.

Is there an [observed, inferred, or projected] continuing decline in number of “locations”?

Yes. Observed.

There is an observed decline in the number of locations. Four sites, representing two locations, are now extirpated.

Is there an [observed, inferred, or projected] continuing decline in [area, extent and/or quality] of habitat?

Yes

There is an observed continuing decline in the quality and extent of available habitat. Invasive species have eliminated or altered the conditions that this species requires for survival, including at a site on Ojibway Prairie. Species such as European Common Reed and Autumn Olive continue to spread and threaten to further impact the quality and extent of habitat.

Are there extreme fluctuations in number of subpopulations?

No

All known sites are within a single subpopulation.

Are there extreme fluctuations in number of “locations”?

No

Are there extreme fluctuations in extent of occurrence?

No

The species is restricted to a small region, so extreme fluctuations in the EOO are unlikely.

Are there extreme fluctuations in index of area of occupancy?

No

The IAO has not been previously calculated. However, due to the perennial nature of the plant, extreme fluctuations are not expected.

Number of mature individuals (by site)

The number of individuals at each site is based on a count of mature culms conducted by Ryan Morin in 2022.

Ojibway Prairie Provincial Nature Reserve: 85

Chappus Street: 45

(Northway Avenue) excluded: (24)

Total: 130

Based on fieldwork conducted by Ryan Morin (2022)

Quantitative analysis

Is the probability of extinction in the wild at least 20% within 20 years [or 5 generations], or 10% within 100 years]

Unknown

An analysis has not been conducted.

Threats

Was a threats calculator completed for this species?

Yes (see Appendix 1)

Overall assigned threat impact: High (2023)

Key threats were identified as:

1. Other Ecosystem Modifications (invasive species) (IUCN 7.3) – High impact
2. Fire and Fire Suppression (IUCN 7.1) - Medium to High impact
3. Recreational Activities (IUCN 6.1) - Low impact
4. Climate Change and Extreme Weather (IUCN 11) - Unknown impact

What limiting factors are relevant?

• Shade intolerant
• Range restricted in Canada
• Specific habitat requirements

Rescue effect (from outside Canada)

Status of outside population(s) most likely to provide immigrants to Canada.

Critically Imperilled to Imperilled

The species is ranked S1S2 (Critically Imperilled to Imperilled) in adjacent Michigan, and S1 (Critically Imperilled) in New York.

Is immigration known or possible?

Possible

Immigration is possible from sites in adjacent Michigan.

Would immigrants be adapted to survive in Canada?

Possibly

Lack of data to make a confident assessment; however, it is assumed to be possible.

Is there sufficient habitat for immigrants in Canada?

No

Limited habitat is a key factor in the limited range of the species in Canada.

Are conditions deteriorating in Canada?

Yes

Are conditions for the source (that is, outside) population deteriorating?

Yes

The populations in surrounding jurisdictions are also Critically Imperilled and are experiencing similar threats.

Is the Canadian population considered to be a sink?

No

Is rescue from outside Canada likely, such that it could lead to a change in status?

Unlikely

Rescue from outside of Canada is unlikely, due to limitations being driven by habitat loss and declining populations.

Wildlife species with sensitive occurrence data (general caution for consideration)

Could release of certain occurrence data result in increased harm to the Wildlife Species or its habitat?

No

The species does not currently face pressure from harvesting or other threats associated with disclosure of its locality. No additional localized threats in the Windsor area are predicted.

Status history

COSEWIC status history: Designated Endangered in November 2024.

Status and reasons for designation

Status: Endangered

Alpha-numeric codes: B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i,ii); D1

Reason for change in status: Not applicable

Reasons for designation: This large perennial rush has a very restricted range in Canada, where it is known from remnant patches of tallgrass prairie in Windsor, Ontario. The Canadian population has declined to 130 flowering stems at two extant sites. Historically the plant has lost habitat to agriculture, housing, and transportation infrastructure, and continues to be threatened with habitat degradation due to invasive plants and fire suppression.

Applicability of criteria

A: Decline in total number of mature individuals

Not applicable.

Insufficient data to reliably infer, project, or suspect population trends

B: Small range and decline or fluctuation

Meets Endangered, B1ab(i,ii,iii,iv,v)+2 ab(i,ii,iii,iv,v)

The EOO (4 km²) and IAO (4 km²) are both below the threshold for Endangered, and the population is known to occur from (a) fewer than 5 locations (that is, 2); and (b) there is an observed continuing decline in the (i) EOO, (ii) IAO, (iii) extent and quality of habitat, and (iv) number of locations and an inferred continuing decline in (v) the number of mature individuals.

C: Small and declining number of mature individuals

Meets Endangered, C2a(i,ii)

There is a projected continuing decline in the number of mature individuals, with a single subpopulation of only 130 individuals, below the threshold of 250.

D: Very small or restricted population

Meets Endangered, D1

Number of mature individuals observed (130) is fewer than the threshold of 250

E: Quantitative analysis

Not applicable.

Analysis not conducted

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2022)

Wildlife Species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)*

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)**

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)***

A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

*

Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.

**

Formerly described as “Not In Any Category”, or “No Designation Required.”

***

Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.

Wildlife species description and significance

Name and classification

Current classification:

Class: Equisetopsida

Order: Poales

Family: Juncaceae

Genus: Juncus

Species: Juncus brachycarpus Engelmann (in Gray 1867)

Subspecies in Canada: none

Common names: Brouillet et al. (2010)

English: Short-fruited Rush, Shore Rush, White-root Rush

French: Jonc à fruits courts

Indigenous (specify language): none known

Synonyms and notes: There are no synonyms for this species.

Juncus is the largest genus in the rush (Juncaceae) family, containing approximately 300 species globally (Brooks and Clemants 2000). The Latin name brachycarpus is a reference to “short fruit,” which is a diagnostic characteristic of this species, distinguishing it from other closely related rushes.

Description of wildlife species

Short-fruited Rush is a stout, rhizomatous rush with round leaves with interior cross-partitions. The involucral leaf rarely extends beyond the inflorescence, which helps distinguish Short-fruited Rush from the similar-looking rush species found in adjacent habitats throughout Ontario.

The inflorescence is a panicle of 1 to 10 dense, spherical heads, with 30 to 100 flowers per head (cover photo). The capsules that develop from the fertilized flowers are brown and do not exceed the length of the tepals, an important identification feature distinguishing it from similar rush species (Michigan Department of Natural Resources 2023). Unlike some other members of the Juncus genus, the seeds do not have “tails” (a tail-like appendage).

Designatable units

Short-fruited Rush only occurs in a small geographic area in Canada and there are no recognized subspecies or varieties in Canada or elsewhere. A single designatable unit is recommended for the species.

Special significance

Short-fruited Rush is representative of southern Ontario’s rich natural heritage, particularly its tallgrass communities, which have largely been lost due to land conversion that began in the 1800s. Tallgrass prairie and oak savannah habitats have received significant attention in efforts to preserve biodiversity in recent years, and are an important component of the City of Windsor, Ontario, and Canada’s natural heritage.

Aboriginal (Indigenous) knowledge

Aboriginal Traditional Knowledge (ATK) is relationship-based. It involves information on ecological relationships between humans and their environment, including characteristics of species, habitats, and locations. Laws and protocols for human relationships with the environment are passed on through teachings, stories, and Indigenous languages, and can be based on long-term observations. Place names provide information about harvesting areas, ecological processes, spiritual significance, or the products of harvest. ATK can identify life history characteristics of a species or distinct differences between similar species.

Cultural significance to Indigenous peoples

There is no species-specific ATK in the report. However, Short-fruited Rush is important to Indigenous Peoples who recognize the interrelationships of all species within the ecosystem.

Distribution

Global range

Short-fruited Rush is only found in North America (Brooks and Clemants 2000). In the United States, it ranges from Massachusetts in the north to Texas in the south, and inland to Kansas, Oklahoma, and the Midwest; in Canada, it occurs as far north as southern Ontario (Penskar 2004; Figure 1).

Figure 1. Global range of Short-fruited Rush (created by Ryan Morin using QGIS).

Canadian range

Short-fruited Rush has an extremely limited distribution in Canada, restricted to the vicinity of Windsor, Ontario and representing less than 1% of its global range. The species requires specific habitat and has only been identified in remnant tallgrass prairie habitats which, although they were historically dominant locally, have been reduced to a fraction of their previous extent.

The first known collection in Canada was by J. M. Bigelow in 1868 on “low ground, wet in the spring, near Sandwich, Canada west, with J. marginatus” (NYBG2379287) a year after the species was described (Gray 1867).

The current distribution of the species is in small remnant patches of suitable habitat, with the largest patches of potential habitat in the Ojibway Prairie Provincial Nature Reserve in the City of Windsor. Although suitable habitat occurred further northeast in Ontario prior to European settlement, the species has only been reported in the Windsor area.

Fieldwork conducted in 2022 confirmed that one subpopulation exists, including one site in Ojibway Prairie Provincial Nature Reserve and two sites which are, or may be, the result of manipulation (Chappus Street and Northway Avenue; Table 1).

Editorial note: This table has been modified to remove precise location information. Please contact the COSEWIC Secretariat if you require this information.

Manipulated subpopulations

Two of the three extant sites (Northway Avenue and Chappus Street) in the species’ Canadian range have been manipulated. Individuals are believed to have been transplanted to these sites when sod from prairie grassland was moved as part of the recovery efforts for the construction of the Herb Gray Parkway in Windsor and LaSalle, Ontario (Wood 2020; WSP 2022). The plants at the Northway Avenue site were found growing exclusively in transplanted sod in what was previously an old field. Sod was also transplanted to the Chappus Street prairie; this area also contains remnant prairie and it is not clear if the plants originated in the native prairie or are part of the sod transplants. In accordance with the Manipulated Wildlife Species Guideline #4 (COSEWIC 2018), the Northway Avenue site is excluded from the quantitative assessment criteria because the plants have not spread beyond the transplanted sod and have not been demonstrated to have a positive impact on the species. The Chappus Street site may contain plants that are not manipulated, and has therefore been included in this status report.

Population structure

In this document, “population” refers to all Short-fruited Rush individuals in Canada as a single unit. “Subpopulations” are geographically distinct groups within the Canadian population between which there is believed to be little migration or genetic exchange (typically one successful migrant gamete per year or less). This report defines subpopulations as all sites of Short-fruited Rush that fall within the 1-km minimum separation distance, which can be increased to up to 3 km if the gap between suitable habitat is less than 1 km wide, which is consistent with the guidelines prepared by NatureServe (2020). “Site” refers to a geographical locality where Short-fruited Rush occurs or has occurred.

Extant sites are separated by highways, residential developments, and non-contiguous habitat types, but are all considered to consist of a single subpopulation, as none exceed the separation distances above. Individuals occur within small geographic areas that reflect the small fragments of remaining suitable habitat. Genetic studies have not been carried out on Short-fruited Rush in Canada.

Extent of occurrence and area of occupancy

Current EOO

The extent of occurrence (EOO) within Canada is 0.94 km², calculated using a minimum convex polygon that encompasses the known extant sites from 2022 (Figure 2). The two sites are separated by 940 m and buffered by a 1 km corridor.

Figure 2. EOO and IAO of extant sites (created by the COSEWIC Secretariat 2024).

Current IAO

The index of area of occupancy (IAO) in Canada is 4 km², calculated using a 2 x 2 km grid drawn over known sites from 2022 that can be moved to capture the minimum number of grid squares (Figure 2).

Fluctuations and trends in distribution

Due to the limited information available for this species, it is difficult to determine trends over time. The European conversion of prairie to agricultural land in this part of southwestern Ontario throughout the 19th and 20th centuries undoubtedly resulted in a historical reduction of the species’ presence, along with its suitable habitats. At present, the remaining habitat is largely found in protected areas.

A population census for this species was not conducted until 2022, which limits the ability to analyze fluctuations or trends in the number of mature stems. On the basis of the evidence found in 2022 of extirpated sites and the proliferation of invasive species, it is likely that the EOO, IAO, and number of mature individuals of the species have been continuously declining. If all sites were included, the EOO would have been 4.65 km², representing a decline of 82% (Figure 2). If all documented sites including extirpated ones were included, the IAO would have been 12 km² (Figure 2).

Spring Garden Natural Area is a large park in the City of Windsor where the species was reported by Ontario Natural Heritage Information Centre (NHIC) staff in the 1990s. The area where this species was reported was found to be overtaken by European Common Reed (Phragmites australis spp. australis) by 2022 (Morin pers. obs. 2022, Figure 3). Short-fruited Rush was not located elsewhere in the natural area during the 2022 fieldwork.

Figure 3. European Common Reed dominating a site previously reported to contain Short-fruited Rush (Spring Garden) (Morin, August 2022).

In the Ojibway Prairie Complex, the species was reported in 1974 specifically in the area “north of Titcombe Road” by Reznicek and Pratt (Table 1), and was collected by Pratt in 1976 (CAN 129837), but no associated coordinates were provided. Oldham also collected a specimen in 1982 from underneath the power lines (iNaturalist 2023). When visited in 2022, this area, known as the Tallgrass Prairie Heritage Park, was densely vegetated with grasses, including the invasive European Common Reed and native species such as Big Bluestem (Andropogon gerardii). Short-fruited Rush was not detected in 2022. It is possible that a change in the moisture regime or fire suppression has altered the habitat.

Short-fruited Rush has been extirpated from one site and is currently extant at one site in the Ojibway Prairie Provincial Nature Reserve. In addition, two sites in Spring Garden Natural Area and one site in the Reaume Road Prairie are extirpated (Table 1).

The Northway Avenue site and possibly the Chappus Street site are the result of the transplantation of sod by the Ontario Ministry of Transportation during the reconstruction of Highway 401, beginning in 2010, as a permitting requirement under the Ontario Endangered Species Act (2007). Short-fruited Rush seeds or root masses appear to have been transplanted during this effort. It is unknown if the species occurred in either of these sites prior to the prairie relocation activities, although it is highly unlikely that the species was present at the Northway Avenue site due to the absence of suitable tallgrass prairie habitat.

Biology and habitat use

Life cycle and reproduction

Short-fruited Rush is a perennial rhizomatous rush that reproduces both asexually through rhizomes as well as sexually by seed. The seeds are enclosed in a capsule-like fruit and each mature culm can contain several mature capsule-bearing heads. Unlike some other members of the Juncus genus, the seeds in the capsules do not have “tails.” The species is capable of reproducing every year once the individual reaches maturity. Short-fruited Rush can produce several individual mature culms along the rhizome. Eleuterius and Caldwell (1981) studied shoot longevity in several populations of Salt Marsh Rush (Juncus roemerianus), and found that plants can live to up to four years, with approximately 10% of shoots surviving for 40 months. Studies on the age of sexual maturity in Short-fruited Rush have not been undertaken.

Seeds of other rush species do not germinate until the April following ripening, but may remain dormant for 60 years (Bond et al. 2007). Rushes are major contributors to the seedbank in a variety of grasslands, but only low numbers are recorded in higher quality British grasslands (Roberts 1981 in Bond et al. 2007). Buried seeds can remain viable in the soil for 20 years (Wolton 2004 in Bond et al. 2007). For the purposes of this report, the generation time was estimated to be 3 to 10 years, which is based on 2 years for culms and 1 to 8 years for the seedbank to mature.

Habitat requirements

In Ontario, Short-fruited Rush occurs in high quality mesic to wet-mesic tallgrass prairie. Every site has a group of upland prairie associates that include several rare species—White Colicroot (Aletris farinosa; Endangered), Dense Blazing Star (Liatris spicata; Threatened), Tall Tickseed (Coreopsis tripteris; N1N2 [Critically Imperilled to Imperilled in Canada]), and Grey-headed Coneflower (Ratibida pinnata; N3 [Vulnerable in Canada])—as well as some more common species such as Flowering Spurge (Euphorbia corollata), Buffaloberry (Shepherdia canadensis), Big Bluestem, and Grass-leaved Rush (Juncus marginatus). According to Pratt (1979), the soils of Ojibway Prairie are seasonally saturated, and portions of the site can flood in March and April. During the summer months the water table drops 1–-2 m to the depth of the underlying clay.

Across the United States, Short-fruited Rush is reported to occur in a variety of open habitat types, including lakeplain wet prairies and seasonally inundated sandy depressions (Penskar 2004), often in association with rare species and Atlantic Coastal Plain disjuncts. In Michigan, Short-fruited Rush occurs in “hydroxeric” sandy prairies which have fluctuating water tables and are associated with glacial lakeplains and, less frequently, pitted outwash plains (Bassett pers. comm. 2024).

Short-fruited Rush has a low tolerance for shade, and is only found in open habitats without canopy cover. Across North America, it grows in damp clay, peat, or sandy soils, and in wet prairies (Brooks and Clemants 2000).

Movements, migration, and dispersal

Dispersal in Short-fruited Rush has not been specifically studied. However, as is the case for other facets of the species’ biology, inferences can be made based on the other rush species. Short-fruited Rush reproduces by seed and rhizomes. Dispersal in Path Rush (Juncus tenuis), a common and widespread Juncus species, has been studied to understand the plant’s potential for spreading into disturbed habitats (Devlaeminck et al. 2005). Another study found Path Rush “well adapted for dissemination by human or animal agency” (Salisbury 1974), suggesting that Path Rush may utilize wildlife for seed dispersal. It is likely that other species of Juncus, including Short-fruited Rush, can disperse via physical contact with animals that occur in the habitat (zoochory), causing the capsules to break open and exposing the seeds to adjacent suitable habitats. Wet seeds of Path Rush were found to be mucilaginous and aggregating, which may help facilitate adhesion to the feet of birds (Salisbury 2010). This dispersal strategy, which is particularly adapted to seasonally inundated habitats, is likely employed by other members of the genus. Dispersal may also be assisted by terrestrial wildlife. The Windsor area ecosystem supports species such as White-tailed Deer (Odocoileus virginianus), Red Fox (Vulpes vulpes), and Coyote (Canis latrans), which may be capable of longer distance dispersal. Juncus species were found to be the most frequently represented genus in a study on seeds in the feces of wild deer and boar (Sus scrofa; Picard et al. 2016).

Interspecific interactions

Predators and competitors

No specific predators of this species have been identified in the literature, although it is likely susceptible to a variety of graminoid predators. No predators are known to be contributing to a decline in, or limiting the recovery of, this species.

Competitors of Short-fruited Rush have not been specifically studied at the Ontario sites; however, competition with native and non-native species likely occurs at a local scale. European Common Reed was found to invade and take over sites previously occupied by Short-fruited Rush (Figure 3). Stands of Short-fruited Rush in the Ojibway Prairie Complex appear to vary in numbers over the years, with localized extirpations suggesting some competition with local native species, including the dominant Big Bluestem (Figure 4). Big Bluestem appears to respond more vigorously to management measures involving prescribed burns.

Figure 4. Suitable prairie habitat with high species richness in Ojibway Prairie, with a mature seed head of Short-fruited Rush in the centre of the frame (Morin, August 2022).

Host/parasite/disease interactions

No specific parasites or diseases affecting this species are identified in the literature. No parasites or diseases are known to be responsible for the decline of this species or to limit its recovery.

Physiological, behavioural, and other adaptations

There are no specific studies on the physiology or adaptability of Short-fruited Rush. The species is found in wet meadows in tallgrass prairie in eastern North America and is not reported as an invasive species in other parts of the world.

The physiology and adaptability of Soft Rush (Juncus effusus) and Compact Rush (Juncus conglomeratus) have been studied as part of the effort to control them as invasive species. Studies have found that these species lose their competitive advantage over bluegrass (Poa) species as soil moisture decreases (Kaczmarek-Derda et al. 2019; Ashby et al. 2020).

Limiting factors

The species is shade intolerant, is found near its northern limit in Canada, and is reliant on a rare and restricted habitat type.

Population sizes and trends

Data sources, methodologies, and uncertainties

There is a paucity of data on Short-fruited Rush in Ontario due to a variety of factors, including the species’ limited geographic distribution and the difficulty of identifying rush species from photos. Previous estimates of population size are based on rough estimates from previous reports of occurrences.

All historical occurrence data were provided by Ontario’s Natural Heritage Information Centre (NHIC 2022), which has conducted infrequent surveys in remnant prairies in the City of Windsor since the 1990s. Short-fruited Rush was not targeted during these surveys and was treated instead as an incidental species (Oldham pers. comm. 2024).

In August 2022, the report writer investigated potential and historical sites of the species (Table 1) by conducting field inventories of all such sites. All historical records provided by NHIC (2022) that included site coordinates and descriptions were searched in their entirely. Additional sites were searched based on geographic proximity to potential habitat and reports on the public data-sharing platform iNaturalist. In total, complete searches of nine potential sites were carried out over two days, resulting in three sites identified as extant (Table 1). The potential sites were chosen based on historically reported occurrences as well as recent reports of new sites on iNaturalist.

In recent years, data-sharing platforms such as iNaturalist, which allows citizen scientists to submit incidental reports that are confirmed by botanists, have increased the likelihood of detecting species such as Short-fruited Rush.

Abundance

Most verified reports of this species in Canada do not include more than a rough estimate of numbers. There are no historical estimates of the Short-fruited Rush population in Canada. Fieldwork in 2022 resulted a count of 154 flowering stems (mature individuals) across three sites. In the largest tract of remaining habitat, in the Ojibway Prairie Provincial Nature Reserve, 85 flowering stems were counted in 2022 in an approximately 2,500 m² patch. Larger, dominant graminoids such as Big Bluestem make detecting Short-fruited Rush individuals more difficult and may result in an underestimate of numbers at the site. The Chappus Street site is south of Highway 401 (Herb Gray Parkway) and E. C. Rowe Expressway on Ministry of Transportation land. This site was reported on iNaturalist in 2013, 2019, and 2020, and a visit in 2022 identified 45 flowering stems. The Northway Avenue site, adjacent to Highway 401 (Herb Gray Parkway) in Windsor on public lands, was found to be supporting 24 flowering stems in 2022; however these plants were found growing in transplanted sod and are therefore excluded from this assessment. The population count undertaken in 2022 is likely an underestimate due to factors that could hinder the ability to detect the species, such as the extent of private property and fences surrounding the remaining habitat fragments. Undetected sites could potentially exist on private property in the area surrounding or within the existing subpopulation. Even small areas of suitable habitat could potentially contain as many individuals as those found at the occupied sites. However, because the surrounding land is highly developed and suitable habitat is extremely rare, additional persistent occurrences are fairly unlikely.

No population estimates are available for Short-fruited Rush in the United States. However, in Michigan, 15 element occurrences (EO) of J. brachycarpus were observed most recently in or after 1989 (18 total, 3 pre-1980 and likely extirpated). Eleven of the EOs have numerical estimates, ranging from 10 individuals or less (5 EOs), to 10 to 100 (2 EOs), 100 to 250 (3 EOs), and more than 2,000 (1 EO). Non-numerical estimates include “no data,” “locally frequent to abundant,” “frequent,” “occasional,” “locally common,” and “small, localized colony.” If the 15 non-historical EOs are extant and as described in the EO data, this makes approximately 5,000 individuals in Michigan, which may fluctuate significantly from year to year, probably with the water table (Bassett pers. comm. 2024).

Fluctuations and trends

Short-fruited Rush habitat in southwestern Ontario was dramatically reduced by the conversion of prairies to agricultural land across the region in the 19th and 20th centuries. In addition, one site, despite being located in Spring Garden Natural Area, has apparently disappeared due to the habitat being overtaken by invasive species. Since a population census was not conducted until 2022, data on population fluctuations are limited.

Continuing decline^{Footnote 1} in number of mature individuals

Opportunistic observations of this species made while conducting fieldwork on other species have provided an estimate of the size of the subpopulation (NHIC 2022; Oldham pers. comm. 2024). It can be inferred, based on the loss of individuals at four sites, that the number of mature individuals has declined. Some sites, despite occurring in the protected Ojibway Prairie Provincial Nature Reserve, have been extirpated by invasive species, and it can be inferred that the number of mature individuals in the subpopulation has declined. Impacts from invasive species and vegetation densification due to fire suppression suggest that further decline will occur in the future.

Evidence for past decline (3 generations or 10 years, whichever is longer) that has either ceased or is continuing (specify)

Comprehensive population studies have not been undertaken in the past; however, fieldwork in 2022 confirmed that two previously occupied sites (Spring Garden and Reaume Road Prairie) have been adversely affected by invasive species and/or human activity (that is, site is in a suburban area, so includes the mowing of adjacent prairie by property owners, trampling by dogs, and introduction of landscape plants), resulting in the apparent extirpation of these sites. Sites have also been extirpated in the Ojibway Prairie Provincial Nature Reserve. No other specific evidence of decline over the past ten years or three generations is known.

Evidence for projected or suspected future decline (next 3 generations or 10 years, whichever is longer, up to a maximum of 100 years)

According to the threats calculator, the remaining sites could be impacted by invasive species and other significant threats over the next 10 to 30 years (Appendix 1). The threat impact is rated as High, which means a potential 22 to 70% decline due to threat 7.3. The loss of four sites suggests that this type of decline is quite possible.

Long-term trends

The abundance of Short-fruited Rush prior to European contact and the extent of the large-scale conversion of tallgrass prairie and savannah habitats to agricultural lands in southern Ontario are difficult to estimate. Long-term trend data are limited, as are historical data on loss or fluctuations. The greatest threat to the species historically—conversion to agriculture—is assumed to be no longer a threat at the remaining sites. However, other threats, such as habitat loss due to infrastructure (road and utilities) development, fire suppression, climate change, and competition with invasive species, suggest a continuing decline over the long-term.

Population fluctuations, including extreme fluctuations

Population fluctuations have not been studied in the population across time. Given that the species is a rhizomatous, perennial graminoid, extreme fluctuations are unlikely.

Severe fragmentation

It is not known whether the current habitat patches are large enough to support a viable population. However, the species has persisted in these small patches on Ojibway Prairie for at least 150 years and, since more than half the population occurs in this area, the species’ habitat is not considered to be severely fragmented. However, existing plants are unable to disperse beyond their current sites due to the fragmentation of the suburban environment, as well as the severe lack of suitable habitat.

Rescue effect

If Short-fruited Rush becomes extirpated from Canada, natural immigration of individuals from the United States is possible, as the species is still present across the eastern U.S., including on the other side of the Detroit River in Michigan, where it is listed as Threatened. However, the species is unlikely to be able to disperse from populations in the U.S. and Michigan without human intervention.

Threats

Historical, long-term, and continuing habitat trends

Historically, suitable habitat for Short-fruited Rush was greatly reduced throughout the 1800s and 1900s due to the conversion of prairie habitat to agricultural lands. The species likely suffered declines during this time, which nearly extirpated it from Canada. Some fragments of suitable habitat in the City of Windsor have allowed Short-fruited Rush and other prairie specialists to survive. Although prairie habitat in Windsor is no longer threatened by conversion to agricultural land, infrastructure (roads, utilities) development remains a potential threat.

Current and projected future threats

An IUCN threats assessment was conducted for Short-fruited Rush. The nature, scope, and severity of these threats are described in Appendix 1, following the IUCN-CMP (International Union for Conservation of Nature – Conservation Measures Partnership) unified threats classification system (see Salafsky et al. 2008 for definitions and Master et al. 2012 for guidelines). The threats assessment process consists of assessing impacts for each of 11 main categories of threats and their subcategories, based on the scope (proportion of population exposed to the threat over the next 10-year period), severity (predicted population decline within the scope during the next 10 years or 3 generations, whichever is longer up to ~100 years), and timing of each threat. The overall threat impact is calculated by taking into account the separate impacts of all threat categories and can be adjusted by the species experts participating in the threats assessment.

The overall threat impact to Short-fruited Rush is considered to be High, corresponding to an anticipated further decline of between 22 and 70%, with a median value of 40%, over the next 30 years (three generations). These values are to be viewed with caution, as they may be based on subjective information such as expert opinion, although efforts have been made to corroborate the scores with available studies and quantitative data.

Threats to Short-fruited Rush include invasive species, fire suppression, recreational activities, and potentially the effects of climate change, the effects of which are exacerbated in Canada by the species’ small population and extremely limited geographical range. Stochastic events affecting the remaining habitat patches could also have a catastrophic effect on the species’ presence in Canada.

Other ecosystem modifications (invasive species) (IUCN 7.3; overall threat impact high)

Invasive species, including a wide variety of introduced plants and animals, are a threat to many native species across the landscape. Several occurrences where the species was reported to be present historically by the NHIC have since been overtaken by European Common Reed, which is invasive in wetland habitats but can also invade adjacent upland areas due to its rhizomatous growth and strong adaptability, allowing it to dominate habitats and exclude other species. Autumn Olive (Elaeagnus umbellata) is another invasive species that has been altering habitats throughout the region and continues to threaten native species (Preney pers. obs. 2023).

Two of the sites (Tallgrass Prairie Heritage Park and Spring Garden Natural Area) reported by NHIC (2022) to contain stands of Short-fruited Rush were found to have been completely taken over by more dominant species, including the aggressive invasive species European Common Reed. European Common Reed poses a realistic threat to all of the currently remaining sites.

Fire and fire suppression (IUCN 7.1; overall threat impact high-medium)

Tallgrass prairie has been maintained historically by natural fires, but the latter have been suppressed in the region since infrastructure development occurred. All three extant sites continue to be managed through prescribed burning (Preney pers. comm. 2023), and the long-term persistence of these prairie remnants may be dependent on this human intervention. The nearby housing in the area limits the use of prescribed burns.

Although the Ojibway Prairie Provincial Nature Reserve is protected from land development, Short-fruited Rush may still be at risk of decline there due to its specific habitat requirements. The Ontario Ministry of Natural Resources and Forestry conducted the first prescribed burn there in 1978, and these burns have continued over the years (Ojibway Nature Centre 2003). While fire is an important factor in maintaining open habitat, fire regime management may result in an advantage for other prairie species (for example, Big Bluestem) that respond more strongly to post-fire conditions, allowing them to replace species such as Short-fruited Rush and its associates. Studies on annual fire regimes have reported their tendency to favour non-native species rather than the native species targeted, resulting in recommendations for less frequent burns (Tveten and Fonda 1999). The impact of fire suppression or prescribed burn treatments on Short-fruited Rush in Canada is unknown; however, the remaining site on the Ojibway Prairie is close to homes along Malden Road and may experience less intense burns.

Recreational activities (IUCN 6.1; overall threat impact low)

Threats from recreational activities are ongoing and increasing, as the human population of the area increases, with the establishment of informal footpaths or all-terrain vehicle (ATV) use occurring at all of the sites.

Climate change and extreme weather (IUCN 11; unknown impact)

It is unknown what impact climate change may have on this species. In recent years, significant storm events have resulted in the flooding of some natural areas in the City of Windsor, which could benefit this rush.

Number of threat locations

There are two locations based on land ownership, which reflects the potential for threats to be managed successfully. Invasive species, fire regime management, or further land conversion (outside of Ojibway Prairie Provincial Nature Reserve) could result in significant changes or threats to each location within a 10 to 30 year span. The loss of sites at Spring Garden and the Reaume Road Prairie represents a loss of two locations (Figure 2).

Protection, status, and recovery activities

Legal protection and status

The species has not yet been assessed by the Committee on the Status of Species at Risk in Ontario (COSSARO). The Ojibway Prairie Provincial Nature Reserve is afforded protection under the Provincial Parks and Conservation Reserves Act (2006). Transfer of ownership to Parks Canada and designation of the Nature Reserve as part of a National Urban Park is anticipated to occur as early as 2025 (City of Windsor 2024). No other legal status applies to this species in Canada. The species is designated Threatened in Michigan and protected in the state (Natural Resources and Environmental Protection Act 1994; Michigan Department of Natural Resources 2023; Bassett pers. comm. 2024).

Non-legal status and ranks

The species has a rank of S1 (Critically Imperilled) in Ontario (NHIC, January 2022) and N1 (Critically Imperilled, last assessed in 2022) in Canada. The Global Rank is G4G5 (Apparently Secure to Secure, last assessed in 2024; NatureServe 2024). The national conservation rank in the U.S. is N4N5 (Apparently Secure to Secure). In adjacent states, the species is ranked S1S2 (Critically Imperilled to Imperilled) in Michigan, with no change in status as of the most recent technical committee review in September 2019 (Bassett pers. comm. 2023). It is ranked S1 (Critically Imperilled) in New York, but is not ranked (SNR) in Ohio, although Short-fruited Rush occurs in alkaline meadows, swales in alvars, moist clay slumps, and fens in northern Ohio, and in scattered locations farther south in fens and wet meadows in glaciated portions of the state, where it is apparently secure (Gardner pers. comm. 2024). It is falsely reported to occur in Minnesota (Smith 2018; Oldham pers. comm. 2024). The species is ranked S1 (Critically Imperilled) in New Jersey, Pennsylvania, and West Virginia; S2? (Imperilled?) in North Carolina; S3 (Vulnerable) in Georgia and Kansas; S3S4 (Vulnerable to Apparently Secure) in Illinois; S4 (Apparently Secure) in Maryland and Virginia; S4S5 (Apparently Secure to Secure) in Kentucky; Accidental (SNA) in Delaware; historical and exotic (SNA) in Massachusetts (Haines pers. comm. 2024); Not Ranked (SNR) in Vermont (where it is not known to occur, Glynn pers. comm. 2024); and Not Ranked in the remaining 12 jurisdictions where it is found—Alabama, Arkansas, Connecticut, Indiana, Louisiana, Mississippi, Missouri, Oklahoma, Rhode Island, South Carolina, Tennessee, and Texas (NatureServe 2024, Figure 5).

Short-fruited Rush has not been assessed by the IUCN (2023).

Land tenure and ownership

In Canada, Short-fruited Rush occurs on public land (Ojibway Prairie Provincial Nature Reserve), including lands managed by Ontario’s Ministry of Transportation.

Information sources

Anderson, D., pers. comm. 2024. Email correspondence to B. Bennett. April 2024. Plant Ecologist/Botanist, Minnesota Department of Natural Resources.

Ashby, M.A., J.D. Whyatt, K. Roger, and R. H. Marrs. 2020. Quantifying the recent expansion of native invasive rush species in a UK upland environment. Annals of Applied Biology 177:243-255.

Bassett, T., pers. comm. 2023. Email correspondence to R. Morin. July 2023. Conservation Associate – Botanist, Michigan Natural Features Inventory, Michigan State University Extension.

Bassett, T., pers. comm. 2024. Email correspondence to B. Bennett. September 2024. Conservation Associate – Botanist, Michigan Natural Features Inventory, Michigan State University Extension.

Bender, M.H., J.M. Baskin, and C.C. Baskin. 2000. Age of maturity and life span in herbaceous, polycarpic perennials. Botanical Review 66:311-349.

Bond, W., G. Davies, and R.J. Turner. 2007. The biology and non-chemical control of rushes (Juncus spp.). Website: https://gardenorganic-assets.s3.eu-west-2.amazonaws.com/documents/juncus-spp.pdf [accessed 15 May 2024].

Brooks, R.E., and S.E. Clemants. 2000. Juncus. Pp. 211-255, in Flora of North America Editorial Committee (eds.). Flora of North America: North of Mexico. Vol. 22: Magnoliophyta: Alismatidae, Arecidae, Commelinidae (in part), and Zingiberidae, Oxford University Press, New York.

Brouillet, L., F. Coursol, S.J. Meades, M. Favreau, M. Anions, P. Bélisle, and P. Desmet. 2010. VASCAN, the Database of Vascular Plants of Canada. Website: http://data.canadensys.net/vascan [accessed August 2023].

City of Windsor. 2024. National Urban Park. Website: https://letstalk.citywindsor.ca/national-urban-park-windsor [accessed August 2024].

COSEWIC. 2018. COSEWIC Guidelines on Manipulated Wildlife Species. Website: https://COSEWIC.ca/index.php/en/reports/preparing-status-reports/guidelines-manipulated-wildlife-species.html#:~:text=COSEWIC%20will%20generally%201%20not,geographically%20or%20genetically%20distinct%20from [accessed August 2024].

DeFilipps, R.A. 1964. A taxonomic study of Juncus in Illinois. American Midland Naturalist 71(2):296-319.

Devlaeminck, R., B. Bossuyt, and M. Hermy. 2005. Seed dispersal from a forest into adjacent cropland. Agriculture, Ecosystems and Environment 107:57-64.

Eleuterius, L.N., and J.D. Caldwell. 1981. Growth kinetics and longevity of the Salt Marsh Rush Juncus roemerianus. Gulf Research Reports 7(1):27-34.

Gardner, R., pers. comm. 2024. Email correspondence to B. Bennett. April 2024. Chief Botanist, Ohio Division of Natural Areas and Preserves, Department of Natural Resources, Columbus, Ohio.

Gray, A. 1867. Manual of Botany of the Northern United States – Edition 5. Ivison, Phinney, Blakeman, and Co., New York. 542 pp.

Gylnn, G., pers. comm. 2024. Email correspondence to B. Bennett. April 2024. Botanist, Vermont Agency of Natural Resources, Barre, Vermont.

Haines, A., pers. comm. 2024. Email correspondence to B. Bennett. April 2024. Senior Research Botanist, Native Plant Trust, Canton, Maine.

iNaturalist. 2023. Online database. Website: https://www.inaturalist.org/observations?taxon_id=164255 [accessed xxx xxxx].

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Kaczmarek-Derda, W., M. Helgheim, J. Netland, H. Riley, K. Waernhus, S. Øpstaeds, L. Østrems, and L.O. Brandseater. 2019. Impacts of soil moisture level and organic matter content on growth of two Juncus species and Poa pratensis grown under acid soil conditions. International Journal of Weed Biology 59:490-500.

Master, L.L., D. Faber-Langendoen, R. Bittman, G. A. Hammerson, B. Heidel, L. Ramsay, K. Snow, A. Teucher, and A. Tomaino. 2012. NatureServe conservation status assessments: factors for evaluating species and ecosystems risk. NatureServe, Arlington, Virginia. Website: https://www.natureserve.org/publications/natureserve-conservation-status-assessments-factors-evaluating-species-and-ecosystem [accessed 2023].

Michalski, S., and D. Walter. 2007. Synchronous pulsed flowering: Analysis of the flowering phenology in Juncus (Juncaceae). Annals of Botany 100(6):1271-1285.

Michigan Department of Natural Resources. 2023. Threatened and endangered species list. Website: https://www.michigan.gov/dnr/managing-resources/wildlife/wildlife-permits/threatened-endangered-species/threatened-and-endangered-species-list [accessed May 2023].

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Natural Heritage Information Centre (NHIC). 2022. Ministry of Northern Development, Mines, Natural Resources and Forestry (NDMNRF). Element and observation data provided July 14, 2022.

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NatureServe. 2024. NatureServe network biodiversity location data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Website: https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.140303/Juncus_brachycarpus [accessed April 2024].

Ojibway Nature Centre. 2003. Website: https://www.ojibway.ca/index.htm [accessed October, 2022].

Oldham, M.J., pers. comm. 2024. Email to B.A. Bennett. July 2024. Botanist (retired), NHIC, Peterborough, Ontario.

Penskar, M.R. 2004. Special plant abstract for Juncus brachycarpus (Short-fruited Rush). Michigan Natural Features Inventory, Lansing, Michigan. 3 pp.

Picard, M., R. Chevalier, R. Barrier, Y. Boscardin, and C. Baltzinger. 2016. Functional traits of seeds dispersed through endozoochory by native forest ungulates. Journal of Vegetation Science 27:987-998.

Pratt, P.D. 1979. A preliminary life science inventory of the Ojibway Prairie Complex and surrounding area. The City of Windsor and the Ontario Ministry of Natural Resources, Chatham. 163 pp.

Salafsky, N., D. Salzer, A.J. Stattersfield, C. Hilton-Taylor, R. Neugarten, S.H.M. Butchart, B. Collen, N. Cox, L.L. Master, S. O’Connor, and D. Wilkie. 2008. A standard lexicon for biodiversity conservation: unified classifications of threats and actions. Conservation Biology 22:897-911.

Salisbury, E.J. 1974. The reproduction of Juncus tenuis (Juncus macer) and its dispersal. Transactions of the Botanical Society of Edinburgh 42(2):187-190.

Smith, W.R. 2018. Sedges and Rushes of Minnesota: The Complete Guide to Species Identification. University of Minnesota Press, Minneapolis, Minnesota. 696 pp.

Tveten R.K., and R.W. Fonda. 1999. Fire effects on prairies and oak woodlands on Fort Lewis, Washington. Northwest Science 73:145-158.

Williams Sale Partnership Global Incorporated (WSP). E&I Canada Limited. 2023. Tallgrass Plant Community Assessment Ojibway Prairie Complex, City of Windsor.

Williams Sale Partnership Global Incorporated (WSP). 2024. Right Honorable Herb Gray Parkway. Website: https://www.hgparkway.com/ [accessed August 2024].

Collections examined

No collections were examined for the preparation of this report.

Authorities contacted

• Bassett, T. Conservation Associate – Botanist. Michigan Natural Features Inventory, Michigan State University Extension
• de Forest, Leah. Ecosystem Scientist, Parks Canada, Lunenberg, Nova Scotia
• Pickett, K. Environment and Climate Change Canada, Canadian Wildlife Service. Email response received 14 January, 2022
• Preney, Tom. Biodiversity Coordinator, The Corporation of the City of Windsor. Email correspondence 12 December 2023
• Taylor, T. Natural Heritage Information Centre, Ministry of Northern Development, Mines, Natural Resources and Forestry (NDMNRF). Email response received 12 January, 2022

Acknowledgements

Funding for the preparation of this report was provided by Environment and Climate Change Canada. The authorities listed above provided valuable data and/or advice. Two of the three sites that were confirmed in 2022 were found as the result of information shared on the iNaturalist platform. The report writer would like to thank those passionate naturalists who donated their reports to help ensure these species cannot disappear from the landscape without notice. Bruce Bennett revised the provisional report with the help of Vivian Brownell, Michael Oldham, Sam Brinker, and Del Meidinger of the Vascular Plant Specialist Subcommittee and comments from Gina Schalk, Holly Bickerton, Marie Archambault, and Karolyne Pickett of Environment and Climate Change Canada. Marie-France Noël, Angel Cyr, Rosana Soares, Tanya Pulfer, Mélanie Plouffe, Alain Filion, and Ryan Collins from the COSEWIC Secretariat also provided assistance in the preparation of this report.

Biographical summary of report writer

Ryan Morin obtained a diploma from Fleming College in Fish and Wildlife in 2010 and graduated from Griffith University with a B.Sc. in Ecology and Conservation Biology in 2012. For over a decade, he has worked in the environmental field, specializing in field botany and fisheries science. Most of his field botany work has centred on the Great Lakes region of Ontario, an area with a high abundance, diversity, and variable distribution of Juncus species.

Appendix 1 – threats assessment on the short-fruited rush

Threats assessment worksheet

Species or ecosystem scientific name

Short-fruited Rush - Juncus brachycarpus

Element ID: 1055998

Elcode: PMJUN010D0

Date: 11/30/2023

Assessor(s): Ryan Morin (report writer), Bruce Bennett (co-chair, facilitator), Del Meidinger (co-chair), Tom Preney (Biodiversity Coordinator, City of Windsor), Holly Bickerton (ECCC), Jenna Siu (ECCC), Sam Brinker (ON NHIC, VP SSC), Vivian Brownell (VP SSC), David Mazerolle (VP SSC)

Assigned overall threat impact:

B = High

Impact adjustment reasons:

High - 22 to 70% decline in mature individuals based on threat 7.3.

Overall threat comments

Generation time of 3 to 10 years was used; Ojibway Prairie 55% of population; Chappus Street 29%; Northway Avenue (16%) was subsequently excluded from the application of quantitative criteria but included in the threat assessment; Chappus and Northway sites are prairie restoration projects. Chappus partly manipulated, partly natural. Ojibway plants in the 'prairie complex,' eastern half. Chappus St. plants all on MTO land, although the site may range wider; many plants “protected” by orange plastic fencing. Northway plants scattered throughout prairie in area–much of area is introduced grasses but rush is only found in transplanted sod areas (MTO land)—no more monitoring is anticipated. There may be more plants at Ojibway based on the iNaturalist observation by Pauline Catling. Going forward, Urban National Park proposal represents an unknown. Mike Oldham’s iNaturalist photos show size of rhizomes.

Classification of threats adopted from IUCN-CMP, Salafsky et al. (2008).