LE3 .A278 2006

2006

Herman, Tom

Acadia University

Bachelor of Science

Honours

Biology

Biology

Winter habitats of Blanding's turtle in a disjunct population complex in southwest Nova Scotia were examined to aid the Blanding's Turtle Recovery Team in conserving critical habitat for this species. Habitat (physical structure, vegetation, water, and substrate depth) and environmental conditions (water and substrate temperature, ice cover, dissolved oxygen, and pH) were examined at eight overwintering (OW) sites, occupied by 46 turtles, and seven paired control (CL) sites. Environmental conditions were measured bi-weekly over two years (January-April 2005 and October 2005-April 2006). To investigate factors affecting turtle location and movement, 25 individuals were regularly radiotracked in the second year. Turtles overwintered fully or partially buried under organic substrate, resting on the bottom, or nestled in submerged vegetation just under the water surface or ice layer. Movement to OW sites was gradual, but departure was rapid, and individual movements during winter did not exceed 11 m; movements were positively correlated with water temperature. Many physical factors and environmental conditions differed among OW sites, but were similar between OW and CL sites. OW sites had variable physical structure and vegetation, and contained abundant of submerged vegetation. Temperature ranged from 0.3-8.6°C in the organic substrate and from 0.3-7.6°C in the water column. Ice cover reached a maximum thickness of 30 cm. In OW sites, median DO ranged from 19.5-91.7 % and median pH ranged from 4.59-5.51. Data suggest that overwintering Blanding's turtles in Nova Scotia can tolerate a wide range of environmental conditions, but that suitable OW sites could be limited because of communal, regular use of several OW sites.

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