A 10,000-Year Record of Environmental Change from Blanding's Turtle {Emydoidea Blandingii) Habitat at Pleasant River Fen, Nova Scotia, Canada

摘要

In Nova Scotia, Blanding's turtles (Emydoidea blandingii) exist in a disjunct population complex at the extreme northeastern area of the species range. Pleasant River Fen in southwestern Nova Scotia provides habitat for one group within the Nova Scotia population. A ca. 10,000-year multi-proxy record to determine environmental variability at Pleasant River Fen demonstrates that the wetland experienced fundamental physical changes in response to regional climate shifts. In particular, the observed increased influx of coarse minerogenic matter into the basin at 5,250 cal BP coincides with the late Holocene cooling. The presence of two prominent charcoal beds at 1,050 and 550 cal BP indicates that larger-scale fire events occurred across the wetland during the Medieval Climate Optimum, possibly due to declined moisture availability. The subsequent expansion of alder and peat moss likely suggests a return to wetter conditions during the Little Ice Age. The study at Pleasant River Fen provides a long-term baseline record on habitat availability for Blanding's turtles. The results of the research suggest that despite climate-induced changes potential habitat persisted at Pleasant River Fen throughout the Holocene. However, fragmentation of the habitat and anthropogenic land use appear to have an influence on the local population dynamics of Blanding's turtles.