Movement, Occupancy, and Detectability of Green Salamanders (Aneides aeneus) in Northern Alabama

Abstract

Green salamanders (Aneides aeneus) are a species of concern throughout their range due to habitat modification and population declines. With few short-term movement studies on the species, the information is vital to better understanding the natural history of green salamanders. Understanding movement patterns and their distribution better are crucial to effectively managing and conserving the species. We studied nightly movements of the species in northern Alabama during the spring breeding season in 2015-2016. During summer (2015-2016), we conducted presence-absence surveys of green salamanders and explored habitat characteristics important to the species distribution in northern Alabama. Adult green salamanders moved on average 4.98 m (SE=0.56) per night, but ended up on average about 1.62 m (SE=0.42) from their start locations at W. B. Bankhead National Forest in Winston County, Alabama. There was strong philopatry and general circular movement patterns. There were no strong environmental factor relationships influencing overnight movement or tortuosity during spring. Summer occupancy surveys were conducted at 148 sites, surveyed between 5-10 times each, on Redstone Arsenal in Madison County, Alabama. Estimated detection probability for surveys was 0.33 (0.15-0.57, 95% CL) based on the top model. More surveyor experience increased detection probability drastically. Detection probability was not clearly related to temperature and relative humidity. Based on the model with the most support, we demonstrate a strong relationship between rock characteristics (rock cover percentage and rock height). We estimated the occupancy of green salamanders at 0.29 (0.18-0.43, 95% CL) in one of two general areas surveyed on the base. The species is patchily distributed throughout its range. Our conclusions about habitat characteristics used by the species and the short-term movements between them are the first step to better understanding patterns important to detecting and managing populations.