Bird's-foot violet (Viola pedata) COSEWIC assessment and status report: chapter 2

Species Information

Bird’s-foot violet is a stemless herb with leaves and flowering stalks arising directly from an erect, non-stoloniferous rhizome. The leaves are primarily three-parted with the divisions being further subdivided into three to five linear segments. The flowers are born singly on the ends of long stalks that generally overtop the leaves. The single flowers are flatter than most other violets and are lilac-purple in colour. The five petals may be all the same colour or the upper two may be darker than the lower three.

Distribution

Bird’s-foot violet occurs in eastern North America from Ontario and New York south to Georgia and west to Minnesota and Texas. Its only Canadian occurrence is in southern Ontario.

Habitat

Typical habitat for the species is black oak savannah on sandy, well-drained, acidic soil with occasional disturbance to limit excessive shading from encroaching trees and shrubs.

Biology

Bird’s-foot violet is a perennial herb that flowers from mid-May to mid-June and again from late September to mid-October. Unlike many other violets, Viola pedata can only reproduce by seed production through cross-pollination.

Population Sizes and Trends

There are five existing populations in Canada. Three occur on private land with one, nine, and 100 plants, and two populations occur on public land with 185 and 6500 plants. The populations on private land are all precarious and at risk from housing development, mowing, and encroachment by trees and shrubs. The largest private-land population--that consisted of 3300 plants in 1987--is now reduced to 100 plants. The smaller population on public land is at risk from ATV use and encroachment by trees and shrubs. The largest population is more secure since it occurs in a provincial park and its protection is part of the park’s Management Plan; in spite of this, the park population has also declined substantially. Although there has been an apparent decline in this population from 10,300 plants in 1987 to 6500 plants in 2001, the very dry weather in 2001 may have caused early senescence in many violets that led to an underestimate of the population size. The decline in total population size for Canada over the last decade is estimated to be 25-50%.

Limiting Factors and Threats

The main limiting factor appears to be lack of suitable habitat. The violet occurs in one of the most developed parts of the country and the oak savannah required by the species is considered provincially rare. The Turkey Point populations are probably protected since they occur in a provincial park, however, management will be needed to maintain the forest openings required by the species. The St. Williams Forest Station site occurs on public land but bird’s-foot violet will decline there unless management is undertaken to maintain some of the open savannah habitat that is now present. The Brantford site occurs on private property that could be further developed and the present landowners are uninterested in management to maintain the species. This site will probably disappear. The other two private-land sites are so small and precarious that they are not likely to survive for long.

Special Significance of the Species

In Canada, Viola pedata is rare and occurs along the northern edge of the species’ range. Itis an important food source for several species of butterflies, especially for the Regal Fritillary (Speyeria idalia). This butterfly is at risk in many states in which it occurs. The Regal Fritillary may still occur sporadically in Ontario, but probably no longer has permanent populations, likely due to the historic reduction of the larval food plant.

Violets have a rich ethnobotanical history, and First Nations’ use of Viola pedata is no exception.