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Western Painted Turtle (Chrysemys Picta Bellii)

Special Significance of the Species

Populations at the extremes of a species’ range represent reservoirs of genetic variation for potential future adaptation to changing environmental conditions. Janzen (1994 b) noted that annual variation in offspring sex ratios of Western Painted Turtles were highly correlated with variation in mean July air temperature. This relationship implies that even modest increases in mean temperature (< 2 °C) in the more southern parts of this species’ range could drastically skew sex ratios and an increase of 4°C could eliminate the production of male offspring. Species with TDSD may not be able to evolve rapidly enough to counteract this negative trend (e.g., Willette et al. 2005, Morjan 2003 b), in which case Canadian Western Painted Turtle populations may play a critical role in this species’ long-term survival assuming that higher winter temperatures enable it to expand its range northward.

The Western Painted Turtle is one of only two extant indigenous species of turtle west of Ontario. Although it is not of direct economic value in Canada, it likely plays an important role in the food web of lakes, ponds and their riparian zones.