Wetland ecosystems are often both spatially and temporally variable, causing wildlife to utilize several different wetlands across a season. These species may function similar to a metapopulation, where movement between wetlands is vital for maintaining population stability, and therefore characteristics such as wetland quality and connectivity are likely to influence demographic processes. Because of this, semi-aquatic species are particularly vulnerable to habitat degradation and fragmentation. The ecology of semi-aquatic freshwater turtles is especially complex because individuals often make long distance movements among a variety of habitats for mating, foraging, basking, aestivating, and overwintering purposes. I investigated the movement patterns and occupancy dynamics of the spotted turtle (Clemmys guttata) in a highly urbanized landscape in northern Virginia, 20 miles outside of Washington D.C. I radio-located 30 adult and 10 juvenile turtles every 48 hours across the active season (March-August) in 2017 and 2018. Average daily movement and home range sizes (autocorrelated kernel density estimates) were calculated. I used these outputs as response variables in generalized linear mixed models and tested for effects of sex, age, climatic, and landscape features, as well as interactions among these. I also examined the occupancy dynamics of wetland patches using the same covariates.
Results/Conclusions
Juvenile turtles exhibited smaller daily movement and home range sizes than adult turtles. There was no difference in movement metrics between males and females, despite differences in life history strategies (i.e. female nest movements). Turtle movement was strongly associated with precipitation and wetland depth, and home range size had an inverse relationship with road density. Road crossing frequency was correlated with precipitation, with no apparent influence from age or sex class. Variation in occupancy probability was best explained by climatic covariates, rather than habitat quality. This may be a function of the limited wetland availability, therefore forcing turtles to occupy sub-optimal patches. Because spotted turtles are equally dependent on both aquatic and terrestrial habitats, are relatively vagile, and may make large movements between wetland patches, it is recommended that this species should be managed using a landscape conservation approach. Further, conservation of wetland matrices and the connectivity among them, rather than individual patches, is vital for the population stability of this species and other sympatric semi-aquatic wildlife.