Using spatial ecology data to inform development and mitigation of a trap rock quarry in Blanding’s turtle (Emydoidea blandingii) habitat

Abstract

Mining practices can negatively impact turtles through degradation of wetlands and surrounding upland habitat, alteration of movement corridors, accidental mortality, and increased risk of nest and turtle predation. These impacts, in turn, can cause changes in patterns of energy allocation, skewed sex ratios and changed demography, which may ultimately lead to population declines. The aim of my study was to describe the demography of, and identify critical habitat for, a population of globally-endangered Blanding’s turtles (Emydoidea blandingii) inhabiting an area of interest for development of a trap rock quarry. In addition to generating important knowledge about population ecology and habitat use, my study can serve as the “before” study in a BeforeAfter Control-Impact (BACI) study quantifying impacts of quarrying on turtles. Using radiotelemetry, GPS dataloggers, and capture-mark-recapture surveys, data were collected at an impact (quarry) site and a control site, and thermal data were collected during overwintering using iButtons. I captured 56 turtles at the impact site and 13 at the control site, and estimated population sizes were 79.6 +/- 17.9 (1.84 turtles/ha) and 16.0 +/- 21.2 (0.32 turtles/ha), respectively. Body size was larger at the control site, but body condition was similar at both sites. Daily distances moved and home range sizes did not differ between sites, and were generally smaller than conspecific values reported in the literature. I identified nesting (15 impact, 2 control) and overwintering (12 impact, 7 control) sites, both considered critical habitats. Overwintering water depth ranged from 30-150 cm (before ice-on) and turtles overwintered at temperatures reported previously in the literature (1.5 to 0.5 ºC). My data can be used to quantitatively inform quarry development and mitigation strategies, essential components to balancing the needs of species at risk and humans.