Spiny softshell turtle (Apalone spinifera) COSEWIC assessment and status report: chapter 8

Limiting Factors and Threats

Although habitat loss may be the most significant cause of the historic decline of this species, habitat degradation is currently the biggest problem. Several of the largest remaining nest sites are also popular human recreation sites, and human alteration of these sites is increasing. This species is easily disturbed during nesting so increased recreational use of these sites will likely cause a decline in already poor nesting success. The presence of humans may have increased the population size of some predators, such as raccoons, particularly in Rondeau where the campground offers increased access to food throughout the year. Sarcophagid fly infestation of softshell nests has also been noted in the Ontario population, but to what degree this affects hatchling survival is not yet well understood. Environmental contamination may also be having an effect on nesting success. High numbers of infertile eggs at some sites in Ontario have prompted an analysis of contaminant levels in eggs and a manuscript on this topic has been submitted (S. de Solla, pers. comm.). Egg samples were collected from 1997-1999 and are currently being analyzed for contaminant levels. Finally, the decline in crayfish and mollusc populations, for spiny softshell’s diet is specialized, may limit the size and distribution of the spiny softshell population.

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