LE3 .A278 1997

1997

Herman, Tom

Acadia University

Master of Science

Masters

Biology

Biology

The Blanding's turtle population in Nova Scotia is restricted to the southwestern interior in and around Kejimkujik National Park. This is the warmest region in the province, and it is thought that the restricted distribution reflects thermal constraints on reproduction. As well, differences in this population's nesting ecology, as compared with populations in more southern parts of the species' range, are thought to be in response to thermal constraints. This population suffers from high levels of egg failure, even in the absence of predation, and the results of this study show that reproductive success is constrained compared with that in populations elsewhere. Females reach sexual maturity in their late teens or early twenties. Females produce a maximum of one clutch of 4 to 15 eggs per year, and most turtles reproduce less than annually. Nesting occurs from early June to early July, and peaks in the latter part of June. Nests are constructed on southern slopes, only a few meters from water. Though substrates used are more coarse than reports from elsewhere, there is no evidence of substrate selection by females. However, nest sites are significantly warmer than randomly chosen sites on the nesting beaches. The extended egg incubation intervals (82 to over 100 days) and developmental abnormalities observed in this population suggest that reproductive success of Blanding's turtles in Nova Scotia is compromised by low temperatures. Reproductive success may be further reduced depending on the overwintering success of neonates. Upon emergence from the nest, hatchlings do not seek water or vegetation cover, they do not follow slope or a consistent compass bearing, and they do not follow nestmates. Evidence suggests that hatchlings in this population may use aquatic and terrestrial hibernacula. These behaviours are inconsistent with reports from elsewhere.

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