Environmental drivers of juvenile dispersal and adult non-breeding movements in Ambystoma salamanders

Abstract

Understanding the environmental drivers of species’ dispersal and migration patterns is needed to accurately predict climate change impacts on populations. For pond-breeding amphibians, adult movements associated with the breeding period are well studied but major gaps exist in our knowledge of the drivers of adult and juvenile non-breeding movements. Here, we assess environmental drivers of adult and juvenile Ambystoma maculatum (Shaw, 1802), Ambystoma jeffersonianum (Green, 1827) and their unisexual dependants (Ambystoma laterale – jeffersonianum (Uzzell, 1964)) summer and fall non-breeding movements using data from pitfall trapping and radio telemetry tracking. We used generalized linear models to assess the influence of precipitation, minimum temperature, day-of-year, and days since last precipitation on salamander movements. Juvenile summer dispersal movements were related to days since last precipitation in Jefferson Salamander complex individuals and 24-hr precipitation in Spotted Salamanders. Adult and juvenile fall movements were driven by minimum temperature, 24-hr precipitation, and days since last precipitation, and the effect of these environmental factors varied slightly between species and between Jefferson bisexual and unisexuals. Our work indicates changes in both temperature and precipitation will likely impact non-breeding dispersal and migration in these species and, overall, improves our understanding of ecological patterns throughout their entire life cycle.