Terrestrial species at risk: COSEWIC summaries for eligible species, January 2017, part 2

Part 2: Nine-spotted Lady Beetle to Wrinkled Shingle Lichen

13. Nine-spotted Lady Beetle

Scientific name: Coccinella novemnotata
Taxon: Arthropods
COSEWIC Status: Endangered
Canadian range: British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec

Reason for designation

This species was once common and broadly distributed through southern Canada, from Vancouver Island through the prairies to southern Québec. It has since declined significantly and is now rarely seen. Despite targeted search efforts over the last decade, the species has decreased in abundance relative to other lady beetle species. Specific causes of the decline are unknown. Possible threats include introduction of non-native lady beetles, which could affect this native species through competition, intraguild predation, or introduction of pathogens. Other possible threats include decline in habitat quality through indirect effects of pesticide/chemical use associated with agriculture to control their prey species, urban expansion, and, abandonment and subsequent natural succession of farmland.

Wildlife Species Description and Significance

The Nine-spotted Lady Beetle (Coccinella novemnotata Herbst) is a small beetle (4.7 - 7.0 mm) that is native to North America. Adults are readily identifiable by external morphological features: their wing covers are pale orange to red, with a dark line where the two wing covers meet. They generally have nine black spots on their wing covers, but the size and number of these spots can vary. Furthermore, the head and pronotum are black with white markings. This charismatic species was once one of the more common and widespread lady beetles in North America, playing an important role as a biological control agent of aphids and other insect pests.

Distribution

The Nine-spotted Lady Beetle is a wide-ranging species occurring throughout most of southern Canada with a range that extends along the international border from Vancouver Island to southern Quebec; with northern range limits near: Quesnel, British Columbia; Edmonton, Alberta; Lake Athabasca, Saskatchewan and Roberval, Quebec. The Nine-spotted Lady Beetle also ranges across the continental United States southwards almost to the Mexican border.

Habitat

Nine-spotted Lady Beetles are habitat generalists, known to consume a wide variety of prey across a wide range of habitats. They occur within agricultural areas, suburban gardens, parks, coniferous forests, deciduous forests, prairie grasslands, meadows, riparian areas and isolated natural areas. This broad habitat range reflects their ability to exploit seasonal changes in prey availability across different vegetation types.

Biology

Nine-spotted Lady Beetles have four life stages: egg, larva, pupa and adult, and can have two generations per year. Adults of the spring generation can undergo aestivation to avoid high summer temperatures and lay eggs in early autumn. Adults of the autumn generation congregate over winter and undergo diapause; becoming active and reproducing when temperatures warm in the early spring. This species occupies a wide ecological niche across a wide variety of habitats and temperature regimes in Canada. Little is known on the natural dispersal rates for the Nine-spotted Lady Beetle. In general, lady beetles are very mobile, display low site fidelity, and readily engage in short- and long-distance dispersal. Drivers of dispersal are a combination of prey density and environmental variables such as temperature, wind speed and rainfall. This species does not migrate. Both adult and larval stages are predatory and prey primarily on aphids. In turn, this species is also subject to predation by introduced lady beetles, other invertebrates and vertebrates, and susceptible to parasitoids and pathogens.

Population Sizes and Trends

The historically broad geographic range and prominence of the Nine-spotted Lady Beetle stands in stark contrast to its current distribution. Prior to 1975, this species was widely distributed across North America and was one of the more common lady beetles collected. This species has since declined and is rarely collected despite targeted searches. Over the last decade the Nine-spotted Lady Beetle has continued to decrease in relative abundance when compared to other lady beetles.

Threats and Limiting Factors

The specific causes of decline in the Nine-spotted Lady Beetle are unknown. Possible threats to this species include negative interactions with recently arrived non-native species, such as the Seven-spotted Lady Beetle and the Multi-coloured Asian Lady Beetle, through competition, intraguild predation or indirect effects through the introduction of pathogens. Other possible threats include direct and indirect effects of pesticide/chemical use associated with agriculture to control their main prey species aphids, and habitat loss through urban expansion, abandonment of farmland, and other human disturbances.

Protection, Status and Ranks

There are no laws in Canada that protect the Nine-spotted Lady Beetle, its residence or habitat. The NatureServe global conservation status rank is G2 (imperilled). The species has not been assigned a conservation status rank in Canadian provinces or territories. However, while this species is not currently listed in Québec, it is likely to be designated Threatened or Vulnerable in that province.

14. Nuttall's Sheep Moth

Scientific name: Hemileuca nuttalli
Taxon: Arthropods
COSEWIC Status: Endangered
Canadian range: British Columbia

Reason for designation

This large, showy and conspicuous moth is restricted to Antelope-brush habitat in the Okanagan Valley of British Columbia. That habitat type has declined considerably in quality and extent in the past century and remains under threat due to continued conversion to viticulture, residential and commercial development, and impact of wildfires. This is a rare moth in Canada: very few have been observed since the first record in 1920. Potentially large fluctuations in the population size may affect its long-term viability.

Wildlife Species Description and Significance

Nuttall's Sheep Moths (Hemileuca nuttallii) are large members of the wild or giant silk moth family (Saturniidae). Adults of both sexes have forewing lengths of 32-39 mm with white to pale yellow forewings and bright yellow hindwings framed by a pattern of thick black markings. Larvae are spiny and black, with the final instars approximately 50 mm in length.

Distribution

The global range of Nuttall's Sheep Moth is from the extreme southern portion of the Okanagan Valley in British Columbia, southward to northern Arizona and New Mexico. In Canada, it has been recorded from the south Okanagan Valley from three general areas: 1) Osoyoos, 2) Oliver (precise site unknown), and 3) Vaseux Lake. The most recent records for the species are 2002 near Vaseux Lake and 1986 at Haynes' Lease Ecological Reserve (approximately 8 km north of Osoyoos). It is unknown if the Haynes' Lease occurrence is the same location as historical records labelled ‘Osoyoos' and the precise location of the Oliver record is unknown. Targeted surveys for adults at six sites in 2009 and for larvae at 16 sites in 2014 were unsuccessful. The targeted searches in 2014 included the 2002 site.

Habitat

In Canada, Nuttall's Sheep Moth is found in the bunchgrass shrub-steppe on dry, open slopes at low elevations where the only known Canadian larval host plant, Antelope-brush (Purshia tridentata), is most abundant. The main habitat is the Antelope-brush/Needle and Thread Grass plant community, which is fragmented by habitat loss; less than 33% of its historical mapped distribution remains in approximately 3200 ha in the Okanagan Valley.

Biology

Nuttall's Sheep Moth is univoltine and may have a life cycle that spans 1 - 2 years. The eggs are laid on the host plants in late summer and overwinter, typically hatching in late April or May the following spring. Early instar larvae are gregarious, while later instar larvae are solitary. The 5th instar larva creates a cocoon in leaf litter or a shallow burrow, and the adult emerges later that season or possibly the following year. In Canada, the known flight period is August through early September, although individual moths have shorter life spans (adults do not feed). Adults are diurnal with a peak of activity in the afternoon, and both sexes are rapid, fast fliers. Perched females emit pheromones to attract potential mates.

Population Sizes and Trends

There is insufficient information to determine Nuttall's Sheep Moth population sizes or trends. Thousands of larvae were observed near Vaseux Lake in 1976, and the species was last observed there in 2002. Nuttall's Sheep Moth was last observed at Haynes' Lease in 1986 despite repeated surveys. No population trend data are available but apparently suitable Antelope-brush habitat in the Okanagan Valley has significantly declined in quality, area and extent.

Threats and Limiting Factors

Cumulative habitat loss, degradation, and fragmentation from agriculture (mainly vineyards and orchards) as well as residential and commercial development are the most significant threats to Nuttall's Sheep Moth populations in Canada.

Protection, Status and Ranks

Nuttall's Sheep Moths have no formal protection or status in Canada. It is not ranked by the BC Conservation Data Centre and is considered globally secure.

15. Peary Caribou

Scientific name: Rangifer tarandus pearyi
Taxon: Mammals
COSEWIC Status: Threatened
Canadian range: Northwest Territories, Nunavut

Reason for designation

This subspecies of caribou is endemic to the Canadian Arctic Archipelago, living on the edge of plant growth in polar desert and arctic tundra environments. The current population is estimated at 13,200 mature individuals. From a population high of 22,000 in 1987, the species experienced a catastrophic die-off in the mid-1990s related to severe icing events in some parts of its range. The population was ca. 5,400 mature individuals in 1996, the lowest since surveys first commenced in 1961. Of four subpopulations, two are currently showing an increasing trend, one is stable, and the fourth had fewer than 10 individuals at the last count in 2005, with no evidence of any recovery. The overall population has experienced an estimated three-generation decline of 35%, but has been increasing over the past two decades. The highest-impact threats derive from a changing climate, including increased intensity and frequency of rain-on-snow events negatively affecting forage accessibility in winter, and decreased extent and thickness of sea ice causing shifts in migration and movement patterns.

Wildlife Species Description and Significance

Peary Caribou are the smallest North American caribou. They are mostly white with a slate back and a grey stripe down the front of the legs. In winter, the slate back may turn a dingy brown, and some individuals appear almost entirely white. Antler velvet is slate-coloured instead of brown like deer and other caribou. The antlers tend not to spread as wide as those of other caribou but otherwise they are similar. The skull has a short rostrum and high cranium. The hooves are short and wide. They are genetically distinct from other caribou in Canada.

Peary Caribou are integral components of Inuit and Inuvialuit culture and economy. As the only source of caribou meat for several Arctic communities, they are important in the subsistence economy of local communities, and represented in traditional crafts that are marketed and collected throughout Canada and internationally. Persisting at the limits of plant and animal existence, Peary Caribou are an integral part of Arctic biodiversity and increasingly important in the scientific study of ecosystem response to climate change.

Distribution

Peary Caribou are endemic to Canada in the Northwest Territories and Nunavut. They have the northernmost distribution of all caribou in North America, situated almost entirely within the Canadian Arctic Archipelago, with the exception of Baffin Island. Peary Caribou move relatively long distances, including annual migrations across sea ice, regular movements within multi-island home ranges and erratic large-scale movements among islands during severe winters. Four subpopulations are recognized, based on genetic evidence, extent of inter-island movements, and scientific and local expertise: 1) Banks-Victoria islands, 2) Prince of Wales-Somerset-Boothia, 3) Eastern Queen Elizabeth Islands, and 4) Western Queen Elizabeth Islands.

Habitat

The habitat of Peary Caribou is treeless Arctic tundra primarily within High and Middle Arctic tundra ecoregions. Most of the range can be characterized as a polar desert with short, cool summers and long, cold winters. The growing season is brief (50-60 days) and variable. Snow cover is generally present from September to May (Banks Island) or mid-late June (Melville Island). Land dominated by dry vegetation covers about 36% of the ice-free area within Peary Caribou range while the terrain ranges from relatively flat (south and west) to mountainous (north and east). The climate is also strongly regionalized with east-west and north-south gradients in precipitation and temperature, affecting primary productivity and forage availability. Above-ground plant biomass ranges from < 100 g/m² (Queen Elizabeth Islands and parts of the Prince of Wales-Somerset group) to some areas (Banks Island and Prince of Wales Island) having up to 500-2000 g/m². Peary Caribou have a broad/varied diet and are versatile feeders with diet varying seasonally in relation to available forage and corresponding nutritional content. Essentially all historical Peary Caribou habitat is available and has not been lost or fragmented by industrial or other anthropogenic developments.

Biology

Peary Caribou have several adaptations to their Arctic environment such as compact body size for conserving heat, hooves that allow them to walk on and dig through wind-driven snow, and pelage that provides camouflage. They are adapted to limited plant growth with a highly compressed growing season and long periods of snow-covered frozen standing vegetation.

Peary Caribou are polygynous, living in small groups and maintaining a wide dispersion across the landscape, even during calving and rutting. They are thought to live approximately 15 years in the wild, and have widely variable vital rates. Cows usually produce their first offspring by 3 years of age; under conditions of high forage availability cows can calve every year but this is rare. Peary Caribou cows cope with occasional years of restricted forage access either by not becoming pregnant, or by weaning a calf prematurely. The intergeneration period (the average age of parents of the current year's cohort) cannot be precisely calculated, but is estimated at 9 years.

Population Sizes and Trends

Evaluating trends in abundance for Peary Caribou since the first surveys were conducted in the 1960s is made difficult by irregular frequency in surveys (in time and space), as well as changes in survey design and methodology. From 1961 to 2014, government agencies conducted a total of 154 aerial surveys to estimate Peary Caribou abundance throughout the Canadian Arctic. There has been no single year when the entire range has been surveyed.

The current population of Peary Caribou is estimated at about 13,200 mature individuals. In the early 1960s, when the first population counts were made, there were ca. 50,000 Peary Caribou. The population in 1987 was ca. 22,000 mature individuals. It reached its lowest known point in 1996 at ca. 5,400 animals following die-offs related to icing events that affected the Western Queen Elizabeth Islands subpopulation in particular. Numbers have increased since that time, but have not fully recovered. The Prince of Wales-Somerset-Boothia subpopulation, which comprised almost half of the known Peary Caribou population in 1987, began to decline in the 1980s, for reasons that remain ill-understood. Although the last survey was in 2006, there is no evidence for any recovery today. Banks-Victoria numbers have been increasing in the past decade, but not on Victoria Island. The two northern subpopulations (Western and Eastern Queen Elizabeth Islands) have increased overall since the mid-1990s, although baseline levels are not well known. The overall three-generation population (27 years) decline for Peary Caribou is estimated at 35%, while the two-generation trend is positive (ca. 142%).

Threats and Limiting Factors

The overall calculated and assigned threat impact is Very High-Medium for Peary Caribou. This wide range rank of threat impacts is due to the combined effect of the high number of mostly low-impact threats, and the considerable uncertainty, unpredictability, and potential overlap and interaction of most individual threats.

The highest-impact threat to Peary Caribou arises from the myriad effects of a changing climate, including increased intensity and frequency of severe weather events negatively affecting forage accessibility in the winters, and decreased extent and thickness of sea ice causing shifts in migration and movement patterns. The extent to which such negative effects could be offset by increases in plant productivity is uncertain. Other threats that are known, suspected, or predicted to have negative impacts on reproductive success or survival of Peary Caribou under a warming climate include pathogens (especially Brucella and Erysipelothrix) and increased shipping. Lower-impact direct threats include hunting, energy production and mining, human intrusions from work (non-tourist) activities, year-round military exercises, increases in traffic from snowmobiles, helicopters, and airplanes, competition with Muskoxen and airborne pollution.

Protection, Status and Ranks

COSEWIC most recently assessed this species as Threatened in 2015. Peary Caribou are currently listed under Schedule 1 as Endangered under the federal Species at Risk Act (2011) and were listed as Threatened under NWT's Species at Risk Act (NWT) in 2013. Peary Caribou are co-managed in Nunavut according to the Nunavut Land Claims Agreement and in NWT according to the Inuvialuit Final Agreement, which confer primary wildlife management authority on the Nunavut Wildlife Management Board and the Wildlife Management Advisory Council, respectively.

16. Pygmy Pocket Moss

Scientific name: Fissidens exilis
Taxon: Mossess
COSEWIC Status: Not at Risk
Canadian range: British Columbia, Ontario, Quebec, Nova Scotia

Reason for designation

This species has a very large extent of Canadian occurrence, occurring on both Pacific and Atlantic coasts, and in central Canada. Despite low detectability that confounds attempts to quantify population sizes and trends, the number of known occurrences has increased from 7 to 21 since 2005, and it is expected that more occurrences will be documented with ongoing search effort. Although it is found in some densely populated regions of Canada, including southern Ontario, no declines or direct imminent threats are known for this species. Localized soil disturbance is required for suitable habitat, such that some kinds of human disturbance may actually benefit the species. Although data are lacking in many aspects of its biology, ecology, distribution, and abundance, no evidence suggests that this species is at risk in Canada.

Wildlife Species Description and Significance

Pygmy Pocket Moss (Fissidens exilis) is an ephemeral moss, periodically producing minute (up to 2 mm), 4- to 8-leaved plants from a mat of undifferentiated green filaments, or "protonemata", persisting between periods of reproductive activity on and in the surface soil layer. It can be identified using microscopic features of the leafy plants (gametophores), but the protonemata, which persist between periods of reproductive activity, cannot be visually identified by any means. Spore-filled capsules, supported on 2 - 9 mm stalks, are attached to the apex of each successfully fertilized, mature plant. Pygmy Pocket Moss is most likely to be detected when capsules are present, especially in large colonies.

Distribution

Pygmy Pocket Moss is known from Europe, Asia, Africa, the West Indies, New Zealand and North America. Some authors speculate that it may have been introduced to the last three of these, but conclusive evidence is lacking. Pygmy Pocket Moss was first discovered in North America in 1947, in Cleveland, Ohio, and it is known from at least fifteen eastern US states, as well as from the Canadian provinces of Nova Scotia, Quebec, Ontario, and British Columbia. Some experts believe the species may be introduced in British Columbia.

Search effort for Pygmy Pocket Moss requires specific, intensive approaches that address challenges associated with ephemeral mosses, which can be visually recognized under only certain, sporadic conditions. These measures have not been undertaken, and most known subpopulations were opportunistically discovered.

Habitat

In North America, most Pygmy Pocket Moss has been found largely on bare, moist, at least partly shaded, clay-based soil or loam. It has been collected on the forested banks of streams and ravines, floodplains, bluffs, beaches, roadsides, trails and other environments where bare soil is exposed. Habitat patches are transient and may be unpredictable, resulting from a variety of natural and human-related phenomena. No broad trends in the preferred habitat of Pygmy Pocket Moss are known.

Biology

Pygmy Pocket Moss is ephemeral and exhibits a "fugitive" life history strategy: the life and reproductive cycles of its leafy plants are short (less than a year), not seasonally dependent, and driven largely by abiotic factors. Reduced size allows such species to reach maturity sooner than larger mosses with more protracted developmental processes. It expends relatively high reproductive effort, with virtually every tiny plant producing a spore-filled capsule, and its small spores (less than 20 μm) are characteristic of species with longevity in the spore bank. These traits equip plants to complete their life cycles in transient, early-successional environments, and avoid stress during periods of habitat unsuitability by persisting in forms (spores and underground filaments) that are less vulnerable to unfavourable conditions.

Spores are dispersed from less than 1 cm above the substrate, and most collections of this moss have been made from at least partly sheltered environments, so long-distance spore dispersal may be very infrequent. Dispersal of moss- or spore-laden soil via a range of possible biotic and abiotic vectors may be important.

Population Sizes and Trends

Population sizes and trends are unknown for Pygmy Pocket Moss, and efforts to establish both must take into account challenges presented by the species' ephemeral nature and tiny size.

Threats and Limiting Factors

Some threats can be inferred with reference to the general biology of mosses and the habitats in which Pygmy Pocket Moss has been collected, but no research has demonstrated any specific threats to this species. Some human activities that routinely threaten other plant species may have a neutral or beneficial effect on this species, which relies on localized soil disturbance.

Protection, Status and Ranks

Pygmy Pocket Moss is currently listed as a species of Special Concern under the Canadian Species at Risk Act. It is also protected under the Ontario Endangered Species Act, and at least half of the sites where it has been found are managed by the federal or Ontario government, or by conservation-oriented organizations. Some North American jurisdictions, including British Columbia, have ranked Pygmy Pocket Moss SE (exotic).

17. Pygmy Slug

Scientific name: Kootenaia burkei
Taxon: Molluscs
COSEWIC Status: Special Concern
Canadian range: British Columbia

Reason for designation

In Canada, this small slug is confined to the moist forests of the northern Columbia basin of British Columbia. It is found in moist mixed-wood and coniferous forests and commonly associated with riparian habitats along small creeks. Key habitat requirements include high substrate moisture with abundant woody debris and leaf litter for shelter. Threats include: existing and new roads resulting in fragmentation, increased edge effects, and barriers to dispersal; predation and competition from invasive species; damage to riparian areas associated with livestock grazing; habitat loss and degradation associated with logging activities; and, projected consequences of climate change, including an increase in drought conditions and an increase in both the number and severity of wildfires.

Wildlife Species Description and Significance

Pygmy Slug is the sole member of the newly described genus Kootenaia. As its common name implies, Pygmy Slug is very small with adults usually 9 - 14 mm long. The colour is from dark grey to tan with dense bluish flecking covering the mantle and tail; dark mottling is often present on the mantle. The tail is rounded (lacking a keel) with a series of parallel and oblique longitudinal grooves, which may resemble thin dark stripes. Pygmy Slug is a regional endemic to moist forests of the northern Columbia Basin, an area that contains many unique plants and animals.

Distribution

The global distribution of Pygmy Slug extends from southeastern British Columbia through the Idaho Panhandle to northwestern Montana. In Canada, Pygmy Slug occurs in the Selkirk and Purcell sub-ranges within the Columbia Mountains in southeastern British Columbia. The species is known from 44 sites in the province; the number of sites may continue to expand with increasing search effort. Approximately 36% of the species' distribution is in Canada.

Habitat

In British Columbia, the slugs occur mostly within the Interior Cedar-Hemlock biogeoclimatic zone, which is among the wettest areas in the interior of the province. The slugs have been found in moist mixed-wood and coniferous forests from low to mid-elevations (580 m - 1585 m), where they are commonly associated with riparian habitats along small tributary creeks. High substrate moisture and abundant shelter, such as provided by coarse woody debris or pockets of deep leaf litter, appear to be key habitat requirements. The slugs have been found from 40 - 50-year-old second growth to old growth (>200 years old) stands. Common trees at occupied sites included Western Redcedar and Black Cottonwood; the understorey often contained moisture-loving plants, such as Thimbleberry, Devil's Club, and Lady Fern.

Biology

The natural history of Pygmy Slug is poorly known. The slugs are hermaphroditic, but the exchange of sperm with other individuals rather than self-fertilization is probably the norm. The slugs lay small clutches of eggs, which are relatively large (10% or more of parent body length). The slugs are known to feed on lichens and fungi and probably also consume decaying organic matter in the duff layer. Most observations in British Columbia and the United States have taken place in autumn, when the slugs are active on the forest floor. Juveniles and an unknown proportion of adults probably overwinter. The generation time is approximately 1 year. The small size of the slugs may enable them to exploit small habitat patches provided that their requirements for moisture and shelter are met. Slugs in general are poor dispersers if not aided by humans or by wind or water; no such passive means of dispersal are known for Pygmy Slug, exacerbating the effects of habitat fragmentation on its distribution within the landscape.

Population Sizes and Trends

Population sizes and trends of Pygmy Slug are unknown. Survey efforts have focused on elucidating the distribution of Pygmy Slug rather than on obtaining abundance estimates. Records for the species from British Columbia are from 2007 - 2015, precluding information on population trends.

Threats and Limiting Factors

The Canadian distribution of Pygmy Slug most likely reflects post-glacial expansion from refugia farther south. Its present distribution is probably limited by a short growing season and/or long and cold winters to the north, and drier forest types to the east and west. Low dispersal ability and requirements for moist habitats limit the speed at which the slugs can colonize new habitats.

Pygmy Slug populations are threatened by extreme events associated with climate change, introduced invasive species, fire and fire suppression, logging, roads, and livestock farming and ranching. The greatest threats to the slugs across their Canadian range are deemed to be from droughts and flood events, the frequency and severity of which are predicted to continue to increase under climate change scenarios. Invasive, non-native species that threaten slug populations include introduced gastropods, which are inadvertently spread by humans and which prey on or compete with native species, and other invertebrate predators such as ground beetles, which can be aggressive predators of slugs. Frequency and severity of wildfires is projected to increase with climate change. Due to their low mobility, gastropods are both unable to escape fire events by moving away and are slow to recolonize burnt areas. Logging is prevalent throughout the Pygmy Slug's range and continues to modify and fragment habitats. The effects of logging on slugs may be mitigated to some degree by riparian buffers, which are required along larger water courses containing fish, or which logging companies may leave voluntarily along small, fishless streams where they are not required. Logging roads and other resource roads also continue to fragment habitats.

Protection, Status and Ranks

Pygmy Slug has no official protection or status under the federal Species at Risk Act, B.C. Wildlife Act, or other legislation. Pygmy Slug is ranked by NatureServe as follows: Global status - G2 (imperilled); United States - N2 (imperilled); Canada - N1 (critically imperilled); Idaho: S2 (imperilled); Montana - S1S2 (critically imperilled to imperilled; BC:S1? (possibly critically imperilled). In British Columbia, the species is on the provincial red list of species at risk.

Across the Pygmy Slug's Canadian range, protected lands comprise approximately 20% of the land base and include several provincial parks, provincial Wildlife Habitat Areas established for other species, and other conservation lands. Pygmy Slug has not been recorded from any of the above areas with the exception of one site within a small conservation area. Most of the range and known sites are within provincial forestry lands.

18. Red Crossbill percna subspecies

Scientific name: Loxia curvirostra percna
Taxon: Birds
COSEWIC Status: Threatened
Canadian range: Quebec, Newfoundland and Labrador

Reason for designation

This subspecies is a distinctive taxonomic group endemic to Canada. Previously known to breed only on the island of Newfoundland, it has within the past five years also been documented nesting on Anticosti Island. While the Canadian population is thought to be greater than was understood previously due to the recent discovery of a breeding population component on Anticosti Island, there is no evidence of an increasing trend. On the contrary, this taxon has experienced a substantial long-term decline. Further population decrease is expected based on identified threats, most notably competition and predation from introduced squirrels in Newfoundland, habitat loss due to logging, and a fungal disease affecting Red Pine.

Wildlife Species Description and Significance

Red Crossbill percna is one of 10 recognized forms of Red Crossbill in North America. It is a medium-sized finch and a specialized seed eater having curved and crossed mandibles, muscular hinged jaws, and strong clasping feet for prying open conifer cone scales to access the seeds. Red Crossbill males are dull red, females are greyish-olive, and juveniles are dull grey to brownish and heavily streaked. Compared to other Red Crossbill forms in North America, percna has a relatively stout and deep (tall) bill, larger body size, and darker, duskier plumage.

Each form of Red Crossbill in North America is characterized by minor differences in morphology, genetics, and behaviour. Forms are also referred to as vocal types; each is most readily and reliably identified by spectrographic analysis of their unique flight vocalizations. Recent research suggests that Red Crossbill percna may correspond with Type 8. North American Red Crossbills likely represent a complex of cryptic species. Though weakly differentiated genetically, vocalization may promote reproductive isolation even among groups that are not geographically separated. Red Crossbill percna is significant because it is a distinct taxonomic group restricted to insular Newfoundland and Labrador (hereafter "Newfoundland") and surrounding islands, and Anticosti Island (QC).

Distribution

Red Crossbills (form/vocal type(s) unknown) were historically considered to occur throughout most of Newfoundland, but with an erratic and localized distribution. Their range apparently has contracted since the first half of the 20^th century; the current distribution of Red Crossbill (both percna and other forms) in Newfoundland is not fully understood. Presence of percna/Type 8 in Newfoundland was confirmed during 2005-2011 via audiospectrographic and morphometric analyses on the Avalon Peninsula, and in eastern, central, and western insular Newfoundland. Probable breeding of Type 8 Red Crossbills having morphology within the documented range of values for percna was also documented on Anticosti Island, QC, in summer 2014.

Birds that possibly are percna (i.e., have large bills) have been documented in Nova Scotia, New Brunswick, Québec (on the mainland and Magdalen Islands), and in New England (USA); these sightings may represent areas of irregular irruptions during years of food shortages in core areas of occurrence.

Habitat

All Red Crossbill forms are closely associated with cone-productive forests. Forms vary with respect to bill morphology, with each specialized to feed on particular conifer species. All large-billed crossbills, including percna, are pine forest associates. In Newfoundland, Red and White Pine stands likely represented a significant portion of important habitat for percna in the past; however, these native pines (particularly Red Pine) are currently rare on the Island and do not occur on Anticosti Island. Mature Black Spruce forests, and to a lesser extent Balsam Fir and White Spruce forests, historically and currently provide additional important habitat for percna. Throughout recent history, habitat conversion, forest harvesting, fire, insect damage, and fungal infestations have led to reductions in conifer seed abundance in Newfoundland. Cone consumption by Red Squirrels introduced to Newfoundland in 1963 is implicated as causing significant recent declines in cone availability. Recent projections by the Newfoundland and Labrador (NL) Department of Natural Resources indicate a significant increase in cone production on Newfoundland's Avalon Peninsula over the next two decades. However, a major Spruce Budworm outbreak is expected to occur in Newfoundland and Anticosti Island in the near future; such an outbreak could have a negative effect on cone availability, but may provide some food in the form of insect larvae and pupae.

Biology

All forms of Red Crossbill are dependent on conifer forests for the food resources they provide in the form of conifer seeds; availability of cones highly influences survival and breeding. Red Crossbills are irruptive and undertake movements across a range of spatial scales in search of sufficient cone crops, though some populations (possibly including percna) tend to exhibit more sedentary behaviour. Irrupting birds tend to be reasonably faithful to core breeding areas, to which some return within a few years of the irruption. Red Crossbills are monogamous, form pair bonds, nest in loose aggregations, and forage in flocks. They have a flexible breeding strategy, can have multiple broods, and nest in colder months if conifer seeds are abundant. Other adaptations to extreme variability in conifer seed crops include sexual maturity at a relatively young age, accelerated succession of broods, and tolerance of repeated cooling and slow development of young when food is relatively scarce.

Population Sizes and Trends

Red Crossbills were once relatively common in Newfoundland but have been precipitously and continuously declining since the 1950s. Currently they are rare, with infrequent and erratic sightings on both formal and informal surveys. Numbers of percna comprising the recently confirmed population on Anticosti Island (which is probably breeding there) are unknown but are estimated to be in the high hundreds. The Canadian population of Red Crossbill percna is estimated to be in the low thousands (i.e., 1,000-2,500 mature individuals), based on recent bioacoustic analyses and localized systematic surveys targeting Red Crossbills, as well as data from Christmas Bird Counts, Breeding Bird Surveys, the Québec Breeding Bird Atlas, and anecdotal reports from birdwatchers. Much uncertainty is associated with this estimate because of relatively limited sampling (particularly in remote areas), difficulties associated with surveying irruptive birds, and the possibility that percna likely moves very large distances during times of food shortage.

Threats and Limiting Factors

Threats to percna are not clearly understood due to the general lack of information on the taxon in Newfoundland and Anticosti Island. Probable threats (from highest to lowest apparent/predicted impact) include: i) invasive, non-native species and problematic native species (i.e., competition for food resources and nest predation by introduced Red Squirrels in Newfoundland, fungal infestations affecting native and non-native pines in Newfoundland, and insect outbreaks resulting in reduced cone production or tree mortality); ii) biological resource use (i.e., forest harvesting); iii) natural system modifications (i.e., forest fires and forest fire suppression); iv) transportation and service corridors (i.e., roadways); v) mining and quarrying; and vi) agriculture. At times, birds face starvation if cone crops fail across wide geographic areas; additional causes of mortality for percna are vehicle strikes and predation.

Protection, Status and Ranks

Red Crossbill percna has been listed as Endangered since 2004 under the federal Species at Risk Act and the NL provincial Endangered Species Act. It is also protected under the Migratory Birds Convention Act. It is considered At Risk in the General Status of Wild Species. NatureServe ranks Red Crossbill percna as nationally imperilled (N2) but has not ranked it provincially although it is recommended as S2 in Québec; Red Crossbill in general has been ranked as S2S3 for Newfoundland and S4 for Québec.

19. Sheathed Slug

Scientific name: Zacoleus idahoensis
Taxon: Molluscs
COSEWIC Status: Special Concern
Canadian range: British Columbia

Reason for designation

In Canada, this slug is confined to a small area in the Kootenay region of southeastern British Columbia, generally within 25 km of the Canada-U.S. border. Most records are from older shady coniferous forest stands ranging from approximately 50 to >200 years. The species often inhabits riparian areas and other very moist microsites. Threats include logging and wood harvesting, and projected consequences of climate change including an increase in drought condition and wildfires. A decline is projected in the area, extent, and quality of habitat. The low number of scattered subpopulations makes the species vulnerable to both natural and human disturbances.

Wildlife Species Description and Significance

Sheathed Slug is a small (20 - 24 mm long), slender slug with a keeled tail and longitudinal and oblique grooves on the sides and tail. The colour is solid grey or brownish grey. Small light flecks on the mantle and tail give the slug a bluish tint. Sheathed Slug is a regional endemic to moist forests of the northern Columbia Basin, an area that contains many unique plants and animals.

Distribution

The global distribution of Sheathed Slug includes northern Idaho, northwestern Montana, and southeastern British Columbia. In British Columbia, Sheathed Slug occurs in scattered localities in the Kootenay region, south of 49°22'N within approximately 25 km of the Canada-United States border. Since the early 1990s, over 700 sites have been surveyed for terrestrial gastropods in the Kootenay region; recent surveys specifically targeted this species and other native slugs. There are records for the species from nine sites. The estimated range (extent of occurrence) of the species in Canada is 1,892 km² based on these occurrences.

Habitat

In British Columbia, Sheathed Slug has been found in mainly coniferous forest stands of varying ages, ranging from 40 - 50 years to old growth (>200 years old); most records are from shady, older forests. The slugs often inhabit riparian areas and gullies associated with small, fast-flowing tributary streams, seepage areas, or other very moist microsites. Moist microhabitats and refuges provided by decaying logs appear to be important.

Biology

The natural history of Sheathed Slug is poorly known. It is hermaphroditic (possessing both male and female reproductive organs) and lays eggs. Juveniles presumably overwinter, but the proportion of adults that do so is unknown. The generation time is probably 1 year or slightly more, based on the small body size of the adults and relatively short life spans of arionid slugs in general. The slugs feed on fungi and liverworts, and probably also on other live and decaying vegetation. Movement capabilities of Sheathed Slug are presumed to be low. Slugs in general are poor dispersers if not aided by humans, wind or water; no such passive means of dispersal are known for this species, exacerbating the effects of habitat fragmentation on its distribution within the landscape.

Population Sizes and Trends

Population sizes and trends of Sheathed Slug are unknown. Survey efforts have focused on elucidating the distribution of the species rather than on obtaining abundance estimates. Records for the species from British Columbia are from 2009 - 2014, precluding information on population trends. Ongoing declines are suspected, as habitats continue to be degraded by forestry and other causes. In the United States, Sheathed Slug is thought to be declining due to habitat loss.

Threats and Limiting Factors

The greatest threats to Sheathed Slug populations in British Columbia are deemed to be logging, which continues to alter and fragment habitats, and droughts and flood events, the frequency and severity of which are predicted to continue to increase under climate change scenarios. Other threats include introduced invasive species, fire and fire suppression, roads, and livestock farming and ranching. Climate change and severe weather, fire and fire suppression, and forestry are likely to interact in a cumulative manner. Increased frequency and severity of prolonged summer droughts is expected to exacerbate the effects of logging (both recent and planned) and wildfires on the slug's habitat, resulting in declines in both quantity and quality of habitat.

Protection, Status and Ranks

Most of the distribution and records of Sheathed Slug are on unprotected provincial forestry lands. Only about the 3% of the Canadian range of the species is protected within parks or conservation lands, but it is unknown whether the species occurs in these areas.

Sheathed Slug has no official protection or status under the federal Species at Risk Act, B.C. Wildlife Act, or other legislation. It is ranked by NatureServe as follows: Global status - G3G4 (vulnerable-apparently secure); United States - N3N4 (vulnerable to apparently secure); Canada - N1N3 (critically imperilled to vulnerable); Idaho: S2 (imperilled); Montana - S2S3 (critically imperilled to vulnerable); BC - S1S3 (critically imperilled to vulnerable). In British Columbia, the species is on the provincial red list of species at risk.

20. Spiny Softshell

Scientific name: Apalone spinifera
Taxon: Reptiles
COSEWIC Status: Endangered
Canadian range: Ontario, Quebec

Reason for designation

The continuing decline of this species in Ontario and Québec is attributed to very low recruitment that has resulted from loss of nesting habitat. Suitable nesting and basking sites have been lost and/or degraded by development, altered water regimes (e.g., dams, floods, erosion of river banks), invasive plants, recreational use, and illegal harvest of individuals. Without nest protection, few eggs survive predation by an increased abundance of mammals.

Wildlife Species Description and Significance

Spiny Softshell turtles (Apalone spinifera) are conspicuously sexually size-dimorphic, with males reaching a carapace length of 22 cm, and females 54 cm. The carapace is olive to tan, relatively flat, round to oval and covered in leathery skin, with spiny projections along the anterior edge that are most conspicuous in adult females. Spiny Softshells are well adapted for swimming, with a reduced lower shell, hydrodynamic shape and strongly webbed front and hind feet. The neck is long, and can extend to approximately 3/4 the length of the carapace. The head is relatively narrow and elongate with a long, snorkel-like snout. Members of the family Trionychidae have a global distribution and diverged from other turtles in the Cretaceous. The species is significant because it is the only native representative of the family Trionychidae in Canada. Canadian populations are at the northern limit of the species' range, and are adapted to a northern climate (e.g., extended hibernation). Unlike other Canadian turtles, where the sex of an individual is determined by the temperature of egg incubation, sex of Softshell turtles is genetically determined.

Distribution

Globally, the Spiny Softshell occurs in eastern North America from the New England states through extreme southern Quebec and Ontario, west to Nebraska, south to Texas and across the Gulf states to the Atlantic. The Canadian population is divided into two geographically distinct subpopulations: a Great Lakes/St. Lawrence subpopulation in southern Quebec and a Carolinian subpopulation in southern Ontario.

Habitat

Spiny Softshell inhabits a wide variety of aquatic habitats, including rivers, marshy creeks, oxbows, lakes and impoundments. Common habitat features include a soft bottom with sparse aquatic vegetation, as well as sandbars or mudflats. Overwintering sites are generally in well oxygenated lakes and rivers.

Biology

Spiny Softshell can live for several decades. Sexual maturity occurs late, and likely not before 12 - 15 years for females at the northern limit of the range in Canada. Influenced by climate, the life cycle of the species is characterized by a long hibernation and a short, active growing season. Cumulative heat units during the active season determine the time necessary to complete incubation. Eggs are typically laid in June or July, with an average clutch size of approximately 20. It is thought that most females deposit a single clutch annually, but some females lay two clutches in a single year. The incubation period generally varies from 60 to 75 days, and ambient nest temperatures can delay or accelerate incubation. Natural recruitment is low because of high egg predation.

Population Sizes and Trends

Population sizes are small and declining. In Ontario, the total number of mature individuals is estimated to be fewer than 1000 and continues to decline. Nest survey data from the three largest locations in Canada all suggest declines in the total number of mature individuals of approximately 45% in the past two decades. Future significant declines are predicted based on current threats. In Quebec, historic populations in three drainage basins have been lost or have become unviable. The last remaining population is estimated to have fewer than 50 adult females.

Threats and Limiting Factors

The primary threats are habitat and population fragmentation by infrastructure, alteration of the water regime (flooding of nests) by dams and changing weather patterns, increased recreational and agricultural use of nesting areas and adjacent aquatic habitats by humans (disturbance during nesting, ATV use, horseback riding, watercraft use), invasion of nesting areas by non-native plants (e.g., European Common Reed (Phragmites a. australis)), high populations of mammalian egg predators and egg poachers, injury and mortality from fishing and motor boating (collisions, propellers), and illegal capture of juveniles and adults. Cyanobacterial blooms (e.g., toxin bioaccumulation, impact on prey) may also impact the species. Limiting factors include the time taken to reach maturity, a low rate of recruitment, and the constraint of limited summer heat for completion of incubation and hatchling emergence.

Protection, Status and Ranks

Globally, Spiny Softshell is classified as Least Concern (G5) by IUCN because it has a wide distribution, is abundant, and the global population is considered stable. It has a national rank of N3 (Vulnerable) in Canada, a rank of S3 (Vulnerable) in Ontario and a rank of S1 (Threatened) in Quebec. Spiny Softshell also has a rank of S1 in Vermont. In Canada, COSEWIC first assessed Spiny Softshell as Threatened in 1991 and again in 2002. It has been listed on Schedule 1 of the Species at Risk Act since 2005. In Ontario, it was assessed as Threatened by the Committee on the Status of Species at Risk in Ontario (COSSARO) in 1996. It is protected under the 2007 Endangered Species Act and is also a specially protected species under the Fish and Wildlife Conservation Act. In Quebec, Spiny Softshell was designated as Threatened in 1999 under the Loi sur les espèces menacées ou vulnérables and is afforded protection under the Loi sur la conservation et la mise en valeur de la faune.

21. Unisexual Ambystoma (Jefferson Salamander dependant population)

Scientific name: Ambystoma laterale - (2) jeffersonianum
Taxon: Amphibians
COSEWIC Status: Endangered
Canadian range: Ontario

Reason for designation

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

Wildlife Species Description and Significance

All-female populations of Ambystoma (i.e., unisexuals) are members of the Mole Salamander family Ambystomatidae. Their morphology is variable and is determined by their nuclear genomes. Unisexuals with two or more Blue-spotted Salamander (A. laterale) chromosome complements are black with various amounts of blue flecking, and have relatively short limbs and a narrower head. Unisexuals with two or more Jefferson Salamander (A. jeffersonianum) chromosome complements are larger, grey to brown with a small amount of blue flecking, and have relatively long limbs and a broader head. Unisexuals with two or more Small-mouthed Salamander (A. texanum) chromosome complements are grey, more slender, and have narrow heads.

Unisexual Ambystoma all share a very similar mitochondrial DNA that is distinctly different from any bisexual species. They have a unique genetic system and represent a distinct, monophyletic lineage that arose 3 to 5 million years ago, making them the oldest lineage of unisexual vertebrates known. Eggs normally develop by gynogenesis. This process requires sperm, derived from sympatric bisexual species. The sperm is only used to initiate the development of the eggs and typically is not incorporated in the developing embryo. In rare cases, sperm are incorporated, and when DNA from sperm are incorporated, the ploidy of the embryos increases (i.e., triploid to tetraploid).

Distribution

Unisexual salamanders are found in association with appropriate bisexual species whose males serve as sperm donors. The geographic range of unisexual salamanders in the genus Ambystoma roughly coincides with deciduous and mixed-wood forests in northeastern North America from Nova Scotia and the New England States to Indiana. Their northern limits are in Minnesota, north-central Ontario, and southern Quebec, and they range south to Kentucky. Three designatable units are considered in this report, based on their sperm-donor species. In Canada, unisexual salamanders are found in association with the Blue-spotted Salamander in Nova Scotia, New Brunswick, Quebec, and Ontario; with the Jefferson Salamander in Ontario; and with the Small-mouthed Salamander on Pelee Island in Lake Erie, Ontario. In Canada, unisexual populations of salamanders occur in all known Jefferson Salamander and Small-mouthed Salamander populations, as well as in the majority of Blue-spotted Salamander populations that have been investigated. Unisexual Salamanders can be much more numerous than individuals of sympatric bisexual species that serve as sperm donors.

Habitat

Unisexual Salamanders have the same habitat requirements as their respective sperm-donating species. They are normally found within deciduous or mixed forests containing, or adjacent to, suitable breeding ponds. Breeding ponds are normally ephemeral, or vernal, pools that dry in late summer. Terrestrial habitat is in moist woodlands, where the salamanders find shelter from predators and desiccation under fallen trees or rocks, as well as in mammal burrows. Adults forage during humid conditions at night on the forest floor within ~1 km of the breeding pond. These salamanders also require terrestrial overwintering sites below the frost line.

Biology

In conjunction with individuals of their sperm-donating species, unisexual adults migrate to and from breeding ponds at night very early in spring. Most migration events to and from breeding ponds coincide with rain or very humid conditions. Courtship occurs with sympatric bisexual males and, within a day or two after mating, unisexual salamanders deposit several egg masses on sticks or emergent vegetation at various depths in the breeding pond. Egg deposition may occur under the ice. Duration of egg and larval development is variable and temperature-dependent. Larvae are carnivorous and eat a variety of invertebrates and are also cannibalistic. In Canada, larvae normally transform in July or early August and leave the pond. Juveniles and adults are entirely terrestrial except for the annual breeding period.

Population Sizes and Trends

Estimation of population sizes of unisexual salamanders is difficult because they are morphologically similar to females of their sympatric sperm-donating species. Most of the historical sites surveyed for the Jefferson Salamander in 1990 and 1991 no longer supported either the Jefferson Salamander or unisexual salamanders in 2003 and 2004. Furthermore, at some sites where both Jefferson Salamanders and unisexuals still existed in 2003-2004, there was a notable reduction in the number of egg masses compared to numbers found in earlier surveys. Population sizes of unisexuals vary with respect to the sperm donor and geographic area. All subpopulations of Jefferson Salamanders and Small-mouthed Salamanders also contain unisexuals that can account for ~ 85% of individuals at a site. The percent of unisexuals found in Blue-spotted Salamander breeding ponds is more variable, and some of those ponds have not yielded any unisexuals.

Threats and Limiting Factors

Loss of sexual sperm donors is a limiting factor unique to unisexual Ambystoma because they require the presence of diploid males of their sexual hosts for reproduction. Threats include: i) partial or absolute elimination of suitable habitat by development, including loss of breeding ponds, trees and ground cover; ii) barriers (e.g., roads, silt fences) across migratory routes linked to breeding ponds; and iii) premature pond drying during summer.

Protection, Status and Ranks

Unisexuals coexist with species some of which have a designated conservation status and are morphologically indistinguishable from those species. Connecticut lists A. jeffersonianum "complex" and A. laterale "complex" as state species of special concern. In Ontario, Jefferson Salamander dominated polyploids are unisexuals that require Jefferson Salamander males. Since 2010, these individuals have received the same habitat protection as the Jefferson Salamander under the provincial Endangered Species Act, 2007 (ESA) (see O.Reg. 242/08 s.28). So far, there is no similar regulation for Canadian unisexuals that live with the Endangered Small-mouthed Salamander (A. texanum) on Pelee Island, Ontario, or unisexuals that depend on the Blue-spotted Salamander (A. laterale).

22. Unisexual Ambystoma (Small-mouthed Salamander dependant population)

Scientific name: Ambystoma laterale - texanum
Taxon: Amphibian
COSEWIC Status: Endangered
Canadian range: Ontario

Reason for designation

These unusual unisexual salamanders exist only on one isolated island in Canada (Pelee Island in Lake Erie) and depend on an endangered sperm donor species, Small-mouthed Salamander (Ambystoma texanum), for recruitment. The salamander faces numerous threats that make its continued existence precarious. These include predation and habitat modification by introduced wild turkeys, drainage activities that can cause premature drying of breeding ponds, road mortality during seasonal migrations, urban development, and recreational activities.

Wildlife Species Description and Significance

All-female populations of Ambystoma (i.e., unisexuals) are members of the Mole Salamander family Ambystomatidae. Their morphology is variable and is determined by their nuclear genomes. Unisexuals with two or more Blue-spotted Salamander (A. laterale) chromosome complements are black with various amounts of blue flecking, and have relatively short limbs and a narrower head. Unisexuals with two or more Jefferson Salamander (A. jeffersonianum) chromosome complements are larger, grey to brown with a small amount of blue flecking, and have relatively long limbs and a broader head. Unisexuals with two or more Small-mouthed Salamander (A. texanum) chromosome complements are grey, more slender, and have narrow heads.

Unisexual Ambystoma all share a very similar mitochondrial DNA that is distinctly different from any bisexual species. They have a unique genetic system and represent a distinct, monophyletic lineage that arose 3 to 5 million years ago, making them the oldest lineage of unisexual vertebrates known. Eggs normally develop by gynogenesis. This process requires sperm, derived from sympatric bisexual species. The sperm is only used to initiate the development of the eggs and typically is not incorporated in the developing embryo. In rare cases, sperm are incorporated, and when DNA from sperm are incorporated, the ploidy of the embryos increases (i.e., triploid to tetraploid).

Distribution

Unisexual salamanders are found in association with appropriate bisexual species whose males serve as sperm donors. The geographic range of unisexual salamanders in the genus Ambystoma roughly coincides with deciduous and mixed-wood forests in northeastern North America from Nova Scotia and the New England States to Indiana. Their northern limits are in Minnesota, north-central Ontario, and southern Quebec, and they range south to Kentucky. Three designatable units are considered in this report, based on their sperm-donor species. In Canada, unisexual salamanders are found in association with the Blue-spotted Salamander in Nova Scotia, New Brunswick, Quebec, and Ontario; with the Jefferson Salamander in Ontario; and with the Small-mouthed Salamander on Pelee Island in Lake Erie, Ontario. In Canada, unisexual populations of salamanders occur in all known Jefferson Salamander and Small-mouthed Salamander populations, as well as in the majority of Blue-spotted Salamander populations that have been investigated. Unisexual Salamanders can be much more numerous than individuals of sympatric bisexual species that serve as sperm donors.

Habitat

Unisexual Salamanders have the same habitat requirements as their respective sperm-donating species. They are normally found within deciduous or mixed forests containing, or adjacent to, suitable breeding ponds. Breeding ponds are normally ephemeral, or vernal, pools that dry in late summer. Terrestrial habitat is in moist woodlands, where the salamanders find shelter from predators and desiccation under fallen trees or rocks, as well as in mammal burrows. Adults forage during humid conditions at night on the forest floor within ~1 km of the breeding pond. These salamanders also require terrestrial overwintering sites below the frost line.

Biology

In conjunction with individuals of their sperm-donating species, unisexual adults migrate to and from breeding ponds at night very early in spring. Most migration events to and from breeding ponds coincide with rain or very humid conditions. Courtship occurs with sympatric bisexual males and, within a day or two after mating, unisexual salamanders deposit several egg masses on sticks or emergent vegetation at various depths in the breeding pond. Egg deposition may occur under the ice. Duration of egg and larval development is variable and temperature-dependent. Larvae are carnivorous and eat a variety of invertebrates and are also cannibalistic. In Canada, larvae normally transform in July or early August and leave the pond. Juveniles and adults are entirely terrestrial except for the annual breeding period.

Population Sizes and Trends

Estimation of population sizes of unisexual salamanders is difficult because they are morphologically similar to females of their sympatric sperm-donating species. Most of the historical sites surveyed for the Jefferson Salamander in 1990 and 1991 no longer supported either the Jefferson Salamander or unisexual salamanders in 2003 and 2004. Furthermore, at some sites where both Jefferson Salamanders and unisexuals still existed in 2003-2004, there was a notable reduction in the number of egg masses compared to numbers found in earlier surveys. Population sizes of unisexuals vary with respect to the sperm donor and geographic area. All subpopulations of Jefferson Salamanders and Small-mouthed Salamanders also contain unisexuals that can account for ~ 85% of individuals at a site. The percent of unisexuals found in Blue-spotted Salamander breeding ponds is more variable, and some of those ponds have not yielded any unisexuals.

Threats and Limiting Factors

Loss of sexual sperm donors is a limiting factor unique to unisexual Ambystoma because they require the presence of diploid males of their sexual hosts for reproduction. Threats include: i) partial or absolute elimination of suitable habitat by development, including loss of breeding ponds, trees and ground cover; ii) barriers (e.g., roads, silt fences) across migratory routes linked to breeding ponds; and iii) premature pond drying during summer.

Protection, Status and Ranks

Unisexuals coexist with species some of which have a designated conservation status and are morphologically indistinguishable from those species. Connecticut lists A. jeffersonianum "complex" and A. laterale "complex" as state species of special concern. In Ontario, Jefferson Salamander dominated polyploids are unisexuals that require Jefferson Salamander males. Since 2010, these individuals have received the same habitat protection as the Jefferson Salamander under the provincial Endangered Species Act, 2007 (ESA) (see O.Reg. 242/08 s.28). So far, there is no similar regulation for Canadian unisexuals that live with the Endangered Small-mouthed Salamander (A. texanum) on Pelee Island, Ontario, or unisexuals that depend on the Blue-spotted Salamander (A. laterale).

23. Western Yellow-bellied Racer

Scientific name: Coluber constrictor mormon
Taxon: Reptiles
COSEWIC Status: Threatened
Canadian range: British Columbia

Reason for designation

The Canadian distribution of this snake is confined to arid valleys of south-central British Columbia, an area with intensive agricultural development and an expanding human population and tourism industry. While relatively little is known of this elusive snake, it likely faces similar threats as other large snakes with which it shares its habitat (Western Rattlesnake, Great Basin Gophersnake). Migratory behaviour of snakes between overwintering dens on valley slopes and lowland foraging habitats, together with increasing numbers of roads and traffic volumes, make populations particularly sensitive to road mortality and habitat loss and fragmentation. Life history characteristics, such as small clutch size and infrequent reproduction by females, increase vulnerability of populations to disturbance, persecution, and changes in land use.

Wildlife Species Description and Significance

The racer species complex (Coluber constrictor) has a broad distribution throughout North America, with three subspecies occurring in Canada: Eastern Yellow-bellied Racer (Coluber constrictor flaviventris), Western Yellow-bellied Racer (C. c. mormon), and Blue Racer (C. c. foxii; addressed in a separate status report). Racers are long, slender snakes with whip-like tails. The Eastern and Western Yellow-bellied Racers are olive-green to blue-grey with cream to bright yellow undersides, from which the name "Yellow-bellied Racer" is derived. Juvenile racers have dark saddle-shaped dorsal markings that fade as the snakes mature. Their sleek body form helps make them extremely fast, while their colouration provides excellent camouflage. In Canada, racers are at the northern extent of their global distribution, where they are of high conservation value as such populations often possess unique ecological adaptations. Racers are non-venomous and harmless to humans. They feed mainly on rodents and insects and are beneficial to local ecological processes.

Distribution

Racers are broadly distributed across North America, but the Eastern Yellow-bellied Racer and Western Yellow-bellied Racer have more restricted ranges. In Canada, the distribution of the Eastern Yellow-bellied Racer extends into three discrete river valleys in southern Saskatchewan and one in southeastern Alberta. The Western Yellow-bellied Racer is restricted to the arid south-central interior of British Columbia, where it occurs in five discrete river valleys.

Habitat

In Canada, racers overwinter in communal rock dens. Western Yellow-bellied Racers may also use rodent burrows or other refuges and hibernate singly, as shown for the sympatric Great Basin Gophersnake. Rock dens are often located on south-facing slopes of steep river valleys, and suitable sites appear to be a limited resource within the landscape. During the active season, racers move from their dens into grassland foraging areas in adjacent lowlands. While Eastern Yellow-bellied Racers occur in mixed-grass prairie, Western Yellow-bellied Racers most frequently occur in Ponderosa Pine and Bunchgrass habitats. Both subspecies forage in riparian and valley bottom habitats.

Biology

In more southern areas of their range in the United States, female racers mature at 2 - 4 years of age and produce one clutch of eggs per year, although, depending on body condition, some may reproduce only every second year. Limited data are available on the age of maturity and survivorship of racers in Canada. The generation time is presumed to be 7 - 8 years. Racers mate after emerging from their winter dens in spring. Females lay a clutch of 3 - 12 eggs, which hatch in approximately 2 months (usually August or September), at which time neonates find their way to a den to hibernate for the winter. Individuals often exhibit strong fidelity to specific hibernacula. The diet of juvenile Eastern and Western Yellow-bellied Racers consists mainly of insects, including crickets and grasshoppers. Adult racers will also take larger prey such as small mammals, reptiles, birds, and amphibians.

Population Sizes and Trends

Racers are well-camouflaged, fast, wary snakes, which makes it difficult to accurately estimate population sizes or even their presence/absence. Based on recent research conducted in Saskatchewan and Alberta, it is evident that Eastern Yellow-bellied Racers are uncommon on the Canadian prairies, and that population dynamics may be negatively affected by habitat fragmentation. The Canadian population size is most likely less than 10,000 adults, distributed among four discrete major valleys on the prairies. Within the past 10 years, the population has declined as a result of a terrain slumping event in Grasslands National Park that killed and displaced snakes from the largest known den of this subspecies in Canada.

Western Yellow-bellied Racers in British Columbia are also uncommon, and their numbers have likely declined from historical levels as a consequence of habitat loss associated with the expansion of urban and agricultural areas. There are potentially five subpopulations of Western Yellow-bellied Racers in major river valleys in the arid interior of the province. Continued threats from road mortality and habitat loss, deterioration, and fragmentation suggest that the population is declining.

Threats and Limiting Factors

Both Eastern and Western Yellow-bellied Racers are vulnerable to habitat loss and fragmentation. These snakes exhibit a high degree of fidelity to specific hibernacula, nesting sites, and summer foraging areas, and appear not to tolerate significant disturbance to these habitats. Racers are limited by the availability of suitable den sites and are unlikely to be able to relocate to other areas if dens are destroyed. Large geographic distances or habitat-barriers isolate small subpopulations, further decreasing the probability of individuals dispersing between sites. Both subspecies are regularly killed on roads, but the threat of road mortality varies greatly across their ranges, being considerably greater for the western subspecies. The overall threat impact was rated as "high" for the Western Yellow-bellied Racer and "medium" for the Eastern Yellow-bellied Racer according to the COSEWIC threat calculator.

Protection, Status and Ranks

COSEWIC assessed the Eastern Yellow-bellied Racer as Threatened and the Western Yellow-bellied Racer as Special Concern in 2004. Both are listed in Schedule 1 of the Species at Risk Act. Provincially, the Saskatchewan Wildlife Act and the British Columbia Wildlife Act prohibit unauthorized killing or possession of racers, but they have no legal protection in Alberta. NatureServe lists both the Eastern Yellow-bellied Racer and the Western Yellow-bellied Racer as Secure (G5T5) globally, Vulnerable (N3) in Canada, and Vulnerable (S3) provincially, except in Alberta where racers are considered Unrankable (SU) because of a lack of information. The General Status Rank of C. constrictor (subspecies are not ranked separately) is considered Sensitive (rank 3) in Canada, Sensitive in British Columbia, and At Risk (rank 1) in Saskatchewan. The IUCN lists C. constrictor as a species of Least Concern.

24. Wrinkled Shingle Lichen

Scientific name: Pannaria lurida
Taxon: Lichens
COSEWIC Status: Threatened
Canadian range: New Brunswick, Prince Edward Island, Nova Scotia, Newfoundland and Labrador

Reason for designation

This lichen colonizes mature deciduous trees, most often Red Maple, and is known from 56 occurrences in the Atlantic provinces. Surveys have failed to confirm the lichen is still present in Prince Edward Island, at one of two occurrences in Newfoundland, at two of four occurrences in New Brunswick, and at several of the 49 known occurrences in Nova Scotia. Threats to this species include continuing forest harvesting leading to the removal of host trees, and the impact of climate change, leading to a reduction in the amount of suitable moist climate.

Wildlife Species Description and Significance

The Wrinkled Shingle Lichen, Pannaria lurida, is a leafy lichen forming patches or rosettes that can be up to 10 cm across. It almost always grows on the trunks of deciduous trees. The upper surface is brownish grey and wrinkled. The photosynthetic partner is a cyanobacterium.

Distribution

The Wrinkled Shingle Lichen occurs in Asia, Australia, Pacific Islands, Africa, Asia and America. Three subspecies have been described. The subspecies that occurs in Canada and northeastern USA is reported to be subspecies russellii. There is a possibility that it could be a different subspecies, but no molecular work has been done to substantiate this.

In Canada, the Wrinkled Shingle Lichen is known from 56 occurrences: 49 are in Nova Scotia, four are in New Brunswick, two in Newfoundland and one in Prince Edward Island. There may be undiscovered occurrences, particularly in Nova Scotia and possibly in New Brunswick or even Newfoundland.

Habitat

The Wrinkled Shingle Lichen in Nova Scotia and New Brunswick colonizes mature deciduous trees, most often Red Maple that grow near, but not usually within, imperfectly drained habitats. Hence, this lichen is found on trees close to the edge of treed swamps or floodplains. The only occurrence on Prince Edward Island was on Cedar while the ones in Newfoundland are on White Spruce growing in an unusual habitat on cliffs close to the sea.

Biology

Fungal fruiting bodies are frequent on the Wrinkled Shingle Lichen and provide the only specialized means of reproduction. The spores ejected from the fruit bodies need to land on the trunk of a mature tree, germinate and encounter a compatible strain of the cyanobacterium Nostoc. Once enveloped by the fungus, the cyanobacterium, as a result of its ability to photosynthesize and fix atmospheric nitrogen, supplies the fungus with both carbohydrates and nitrogen. No specialized vegetative reproductive structures, which are common on many other lichens, are produced by the Wrinkled Shingle Lichen. However, fragmentation and reattachment of thalli may provide for very local dispersal on host tree trunks.

Population Sizes and Trends

The estimated population of Wrinkled Shingle Lichen in Canada is about 5,000 individuals but as not all known occurrences were revisited or enumerated and as the number of mature individuals varied greatly at sites, the population may exceed 10,000 individuals. The number of lichens per occurrence ranged from one individual to just over 2,400 at a given occurrence.

A total of 56 occurrences are known from Canada. Of the 24 pre-1986 occurrences discovered before 1986, 19 were revisited and the lichen was not found at 15. The lichen was also found to be absent at two more recently discovered occurrences in Nova Scotia and one in Prince Edward Island. Thus the lichen was absent from 18 of the 56 occurrences amounting to a loss of 32%. It is argued that this loss of occurrences has been accompanied by an equivalent decline in the number of mature individuals of the lichen.

Threats and Limiting Factors

Threats calculator analysis indicated that the overall threat impact to P. lurida was "high to very high" with the major current threat being forest harvest resulting in both loss of host trees and changes in microclimate. The impact of forest harvesting for lumber, firewood, woodchips and biomass is particularly serious because this lichen typically colonizes trees after they have developed rough bark, which takes some 50 years post-harvest. The annual hardwood harvest in Nova Scotia doubled between 1990 and 2000 and is expected to continue with continued harvesting of deciduous trees. The same pattern of decline in the amount of old deciduous forest has also occurred in New Brunswick although most forestry activities are on upland mesic sites.

Less serious threats to the Wrinkled Shingle Lichen are climate change, road construction, development, and pollution. A reduction in rain, longer periods of summer drought and less fog, all of which have been projected for Nova Scotia, could lead to reduced growth or death of the Wrinkled Shingle Lichen. Where road construction or development affects drainage leading to changes in humidity in surrounding or nearby woodland habitats, it may reduce growth or lead to death of the Wrinkled Shingle Lichen. Finally, this lichen is also sensitive to sulphur dioxide and acid rain. While the levels of both these have fallen in recent years, the continuing emissions may overcome the buffering capacity of the host tree bark, rendering it too acidic for this lichen to colonize.

Protection, Status and Ranks

The Global Status of the Wrinkled Shingle Lichen is G3 (Vulnerable) to G5 (Secure). The species is Unranked or Not Yet Assessed in the USA. In Canada, the Wrinkled Shingle Lichen is Unranked.

In Nova Scotia, five occurrences are protected: one in Kejimkujik National Park, one in the Five Islands Provincial Park, another in a municipally owned Common Land, and a fifth in a provincial Nature Reserve. In New Brunswick, one occurrence at Clark Point is in a Protected Natural Area.