Classifications and rationales from February 2011 COSSARO Meeting footnote *
Species groupCommon nameScientific nameCurrent classification under the ESAClassification by COSSARO February 2011
Vascular PlantsNodding PogoniaTriphora trianthophoraEndangeredEndangered
Vascular PlantsPitcher’s ThistleCirsium pitcheriEndangeredThreatened
Vascular PlantsPurple TwaybladeLiparis liliifoliaEndangeredThreatened
Vascular PlantsShowy Goldenrod (Great Lakes Plains population)Solidago speciosaEndangered (one ON population)Endangered (new population)
Vascular PlantsShowy Goldenrod (Boreal population)Solidago speciosaEndangered (one ON population)Threatened (new population)
Vascular PlantsSkinner’s AgalinisAgalinis skinnerianaEndangeredEndangered
Vascular PlantsWhite Prairie GentianGentiana albaEndangeredEndangered
InsectsSkillet ClubtailGomphus ventricosusn/aData Deficient
FishesAtlantic Salmon (Lake Ontario population)Salmo salarExtirpatedExtinct
AmphibiansJefferson SalamanderAmbystoma jeffersonianumThreatenedEndangered
ReptilesButler’s GartersnakeThamnophis butleriThreatenedEndangered
ReptilesTimber RattlesnakeCrotalus horridusExtirpatedExtirpated
BirdsCerulean WarblerDendroica ceruleaSpecial ConcernThreatened
MammalsEastern MoleScalopus aquaticusSpecial ConcernSpecial Concern
MammalsWoodland VoleMicrotus pinetorumSpecial ConcernSpecial Concern


Nodding Pogonia (Triphora trianthophora) is Endangered in Ontario. This globally rare (G3G4) orchid of rich woods is widespread in eastern North American and known in Canada from only two small populations. Both populations are in Ontario’s Carolinian Zone, and the continued survival of one population is not known. This plant is an underground saprophyte depending upon an association with a fungus and only shows above ground when flowering. The species faces a variety of threats including habitat deterioration caused by invasive plants and exotic earthworms as well as herbivory by deer, change in land use, stochastic events, and low genetic diversity.

Pitcher’s Thistle (Cirsium pitcheri) is Threatened in Ontario. This perennial plant lives as a basal rosette for 3 to 11 years and then dies after flowering once. It is a Great Lakes endemic found on shoreline sand dunes on Lakes Huron and Superior in Ontario. Inhabits a provincially rare habitat (Great Lakes coastal dunes) and its life history is specialized in terms of habitat. Many new populations have been discovered in the vicinity of Manitoulin Island in the past 10 years, substantially increasing the population estimate for the province. Many of these populations show signs of increase. The populations outside of Manitoulin are smaller and not faring as well. The reasons for the listing include the vulnerability of populations on shores in Lake Huron and Lake Superior, the specialized life history, and Ontario’s conservation responsibility.

Purple Twayblade (Liparis liliifolia) is Threatened in Ontario, downlisted from Endangered. This inconspicuous terrestrial perennial orchid occurs throughout the eastern and central United States. It occurs in a variety of habitats and colonizes successional habitats not typically visited by botanists. Purple Twayblades are increasing in abundance and distribution in the Midwest, but declining in New England. It occurs in scattered populations in southern and eastern Ontario and there is one recently discovered population in southern Quebec. The discovery of several new populations in recent years has extended its known range in Canada. The majority of the populations comprise few individuals, and the total known population size in Ontario remains small (< 300). Threats to Purple Twayblade include housing development and urbanization, succession, flooding caused by beaver dams, invasive species, small population sizes, and herbivory. Small, scattered populations in Ontario account for its conservation listing. Increased numbers of known populations as a result of enhanced survey effort account for the downlisting from Endangered.

Showy Goldenrod (Solidago speciosa), a perennial, herbaceous plant, occurs as two designatable units (populations) in Ontario; the Great Plains population is Endangered, and the Boreal population is Threatened.

The Great Lakes Plains population occurs in two locations of about 670 and 125 individuals respectively restricted to tallgrass prairie and savanna habitats. One of these populations had declined an estimated 38% between 2003 and 2008. Threats include habitat loss due to house building, cemetery expansion, invasive species and encroachment of woody species due to lack of fire.

Furthermore, the larvae of an unidentified Coleophora moth has been eating the seeds of this plant. Declines in one population and threats to both account for the listing as Endangered.

The Boreal population consists of a single, recently discovered population of about 1110 mature individuals. There is no information on decline in the number of mature individuals or quality of habitat of this population and no direct human threats have been documented. The single population accounts for the listing as Threatened.

Skinner’s Agalinis (Agalinis skinneriana) is Endangered. This globally rare (G3G4) annual species of tallgrass prairie currently occurs as two populations in Ontario, both on Walpole Island. Another population near Windsor, although not seen in 2008, may still be extant. Several populations have apparently disappeared and those remaining are threatened by a variety of factors. This plant is a hemiparasite, and Little Bluestem is one known host species. The disappearance of previously known populations and continuing threats account for the Endangered status.

White Prairie Gentian (Gentiana alba) is Endangered in Ontario. This sprawling perennial can be up to 1 m tall. Its white, spindle-shaped flowers are about 3.5 cm long and cluster near the tip of the stem. In Ontario there is a single extant population in remnant oak savannahs on Walpole Island. There are < 50 individuals in the population, and they are at risk from encroachment by woody species that causes shading. Trampling and genetic contamination through hybridization are additional threats. The single population, specialized and scarce habitat, small number of individuals and ongoing threats support a designation as Endangered.

Skillet Clubtail (Gomphus ventricosus) is Data Deficient in Ontario. This striking dragonfly has dark brown with yellow and green markings and is known from a single specimen collected in Ottawa in 1924. The tip of the abdomen is expanded into a skillet shape. The larvae live in large clean rivers with medium to slow-running waters and silt or clay substrate. This species’ range extends from New Brunswick south to Tennessee and west to northern Minnesota. Despite extensive searches, along the Ottawa River there have been no subsequent records of Skillet Clubtail in Ontario. Its historical status and cause of its disappearance in Ontario are unknown. Possible threats are water quality degradation and invasive species.

The Atlantic Salmon (Salmo salar) population that occurred in Lake Ontario is Extinct. The salmon were once prolific throughout the Lake Ontario watershed, but there has been no record of this population since 1898. The Lake Ontario population was likely potamodromous, completing their life cycle entirely in fresh water with Lake Ontario serving the same function for adult and juvenile Lake Ontario Atlantic Salmon that the ocean did for anadromous populations of Atlantic Salmon. The Lake Ontario population was extinguished through habitat destruction (including deterioration in spawning habitat due to timbering, agriculture, and mills and dams that prevented access to spawning grounds) and over-exploitation by extensive food and commercial fisheries. None of the attempts to re-establish the species through stocking has succeeded, probably for reasons, including invasive species and dietary deficiencies. The Lake Ontario population had previously been assessed as Extirpated by both COSSARO and COSEWIC. The original Lake Ontario Atlantic Salmon strain is no longer available, so that reintroductions have involved different genetic stock. The status of Extinct recognizes that the Lake Ontario population of Atlantic Salmon no long exists.

Jefferson Salamander (Ambystoma jeffersonianum) is Endangered in Ontario because of recent and ongoing declines in population. Since the 2000 status report, our knowledge of the abundance and distribution of Jefferson Salamander has changed and the risk of extinction in this species has increased. Molecular genetic analysis of tissue samples allows identification of individuals and has generated more accurate and precise estimates of numbers and distribution. The new data clarify the relationship between Jefferson Salamander (JJ) and sympatric populations of all female unisexual Ambystoma (LJJ) salamander. In Ontario, all populations of A. jeffersonianum (JJ) also contain unisexual Ambystoma (LJJ). Ambystoma jeffersonianum has not been found in all populations containing LJJ unisexuals, but it is presumed that A. jeffersonianum is or was also present as a sperm donor. Of 87 sites known to have JJ or LJJ salamanders, only about one third still have extant populations of Jefferson Salamanders (JJ), many have fewer individuals of Jefferson Salamanders than originally thought. Unisexual LJJ females outnumber Jefferson females, often by a wide margin. The absolute number and proportion of JJ to LJJ have declined in virtually all ponds where repeated tissue samples have conclusively identified JJ from unisexual LJJ. Threats to the survival of the species include loss of ponds and terrestrial habitat to development, fragmentation of locations by roads and uninhabitable terrain. These changes also can affect local hydrology and the impact on the salamanders is amplified by introduction of predatory fish into ponds. These salamanders can live a long time (~30 years), making them very vulnerable to threats associated with development.

The Butler’s Gartersnake (Thamnophis butleri) is Endangered in Ontario because of small isolated populations and loss of habitat (tallgrass prairie). It is a relatively small, strikingly marked gartersnake that has a restricted range in midwestern North America (Wisconsin, Michigan, Illinois, Ohio, Ontario). In Ontario, it is restricted to four pockets in the southwest, with a series of populations between the Windsor and Sarnia areas, and another fairly substantial population in the Luther Marsh area. The other two areas, in the vicinity of Parkhill and Skunk’s Misery, are of uncertain status, no snakes having been found in either area in recent years. The major threats to the species in Ontario are outright habitat loss and fragmentation of the habitat that remains.

Timber Rattlesnake (Crotalus horridus) has been Extirpated from Ontario. These snakes occur throughout the eastern and central United States, although they are locally extirpated or declining in many areas especially in the northeast jurisdictions. The most recent confirmed record of the species in Ontario was made in the Niagara Gorge in 1941. More recent sightings elsewhere in the province are probably erroneous. The species’ former range may have included Pelee Island and Point Pelee, the Niagara Escarpment, and possibly islands in Georgian Bay. Although the Timber Rattlesnake is currently listed under Ontario’s Endangered Species Act, 2007, most authorities have concluded that this snake is extirpated from Ontario. Based on COSEWIC criteria, we arrive at an Extirpated status as there has been no confirmed record in over 50 years.

Cerulean Warbler (Dendroica cerulea) is Threatened in Ontario. This blue-and-white wood-warbler of northeastern North America occurs mainly in the Ohio and Mississippi watersheds and the Allegheny Mountains. It breeds in relatively large tracts of deciduous forest. Populations of these birds have undergone continuing declines throughout most of its range, including southwestern Ontario. First established in the early 1960s, the population of Cerulean Warblers in southeastern Ontario has been relatively stable. The conservation classification reflects evidence of reduced fecundity in addition to overall declines in range and population size. The major threats to the species appear to be loss of habitat on the wintering range, but there also are concerns about the loss or further fragmentation of the breeding habitat.

Eastern Mole (Scalopus aquaticus) is of Special Concern in Ontario because of its limited distribution and uncertain status in the face of potential habitat threats. This species is widely-distributed in most eastern and central states of the USA, and northern Mexico. In Canada it is restricted to ca. 1000 ha near Point Pelee National Park in southern Ontario. This mole requires soft soils and has a fragmented distribution in Ontario. There is, however, a lack of adequate monitoring effort or quantification of threats that together underline the uncertainty of its conservation status. Although there is some evidence of a decline in distribution, the survey data do not have enough power to draw any conclusions. The range of the Eastern Mole in Canada appears to be limited by availability of suitable soil types which have been extensively modified or covered by intensive agriculture and residential development.

Woodland Vole (Microtus pinetorum) is a species of Special Concern in Ontario because of its limited distribution and lack of data on population status and threats. These small, semi-fossorial mammals are widely distributed throughout eastern North America and reach the northernmost extent of their range in southern Ontario. This species appears to be less common in Canada, and does not reach the high numbers reported from sites further south. The animal has proved difficult to survey and this, combined with limited survey efforts, means that we lack data about the size and status of its populations in Ontario. Potential threats include urban development, agricultural intensification and forest fragmentation. Our knowledge about the status of this species and threats to its persistence has not improved since the last assessment.