Annual variation in timing, orientation and effects of weather on Jefferson salamander (Ambystoma jeffersonianum) and spotted salamander (Ambystoma maculatum) movements in central Kentucky

Annual variation in temporal and spatial patterns of amphibian migration and dispersal are poorly understood. To address this issue, a circular drift fence was installed around an ephemeral pond at the Central Kentucky Wildlife Management Area, Madison County, Kentucky. The pond was checked daily for salamander movements from 17 January 2010 to 26 September 2010 and from 26 January 2011 to 3 August 2011, which corresponded to the activity season. Weather variables examined in relation to amphibian movements included barometric pressure, cumulative precipitation, temperature and relative humidity. Several species used the ephemeral pond during the study but few successfully reproduced. Jefferson salamanders (Ambystoma jeffersonianum) and spotted salamanders (A. maculatum) were abundant and successful breeders and were the focus of this study. Breeding times between the two years varied for both species. Weather associations with prebreeding and postbreeding movements varied within and between years. Declines in barometric pressure were generally the best predictor of salamander movements but mean daily temperature and relative humidity were also associated with movements. Juvenile exiting movements also showed significant associations with cumulative precipitation. Detection of suitable weather reduces mortality from freezing and desiccation and can cause annual differences in breeding periods. Orientation of all prebreeding movements across years, sexes, and species were not statistically different from random, while orientation of postbreeding movements of some years and life stages were statistically different from random. Adult movements were generally oriented north of the pond while juveniles oriented in all directions. By being able to understand and predict habitat use and timing of amphibian breeding movements, better management practices can be implemented to reduce human-induced mortality during movements