Influence of Wetland and Landscape Characteristics on Freshwater Turtle Relative Abundance and Movement Patterns in West Virginia, USA

Abstract

Wetland management practices often alter habitat characteristics to improve the function of the wetland (e.g., removing emergent vegetation for aesthetics or dredging for fish stocking), potentially at the cost of reducing habitat quality for wetland-dependent species such as freshwater turtles. We identified wetland and surrounding landscape characteristics related to painted turtle (Chrysemys picta) and snapping turtle (Chelydra serpentina) relative abundance and snapping turtle movement among wetlands. We surveyed turtles at 36 wetland sites (0.04–7.45 ha) in a mixed-use watershed in north-central West Virginia, USA, where hardwood forests and wetlands have been heavily fragmented by agriculture and roads. We also applied radio transmitters to 40 adult snapping turtles (20 females and 20 males) across 20 wetlands. Snapping turtle relative abundance was positively associated with wetland perimeter, mean substrate depth, mean wetland vegetation cover, and minimum distance from roads, while painted turtle relative abundance was positively related to herbaceous wetland cover. We documented movement among wetlands for 25 snapping turtles (63%), including 12 females and 13 males. The probability of inter-wetland movement decreased with wetland perimeter length and distance to the nearest wetland. Our results suggest that large wetlands with deep substrate and abundant herbaceous vegetation provide high-quality habitat for our focal turtle species and that increasing the density of wetlands could increase snapping turtle population connectivity.