Overnight Movements of Green Salamanders (Aneides aeneus) in Northern Alabama
Understanding movement patterns and their biotic and abiotic correlates is crucial to effectively manage and conserve salamander populations of concern. Because information on Green Salamander (Aneides aeneus) movement patterns is limited, we tested several biological hypotheses about factors affecting their movements on the basis of data from 69 salamanders fluorescently tracked during spring of 2015 and 2016 in the Bankhead National Forest, northern Alabama. We found Green Salamanders primarily in rock crevices but also observed use of trees. Green Salamanders traveled through leaf litter but did not use it as a daily refuge. There was a significant difference between salamander body temperatures in daily refugia and ambient temperatures, indicating that refugia effectively buffer the species from ambient conditions. Green Salamanders moved an average of 4.98 m (95% confidence interval [CI] = 3.88–6.08) per night. Total distance traveled overnight increased with increasing body size for males but decreased with increasing size for females. Individual wandering ratios were affected by body size, with larger salamanders moving in more linear paths than smaller individuals. During nightly monitoring, 23% of salamanders did not leave their starting refuge or returned to it after a night of movement. Net distance movements showed selection of crevices averaging 1.94 m (95% CI = 0.90–2.99) from starting refuges. Our short-term movement study suggests that Green Salamanders use multiple neighboring refuges, follow complex paths in moving between them, and exhibit philopatry to those refuges.Abstract
Mapped overnight movement path of an Aneides aeneus in Bankhead National Forest, northern Alabama, 2015. The path begins in the upper left; it continued up the tree beyond a height we could safely track the individual. This was the only path observed that went up a tree beyond our measurement limits.
Frequency distribution of (A) untransformed and (B) square-root-transformed overnight total distance movements by adult Green Salamanders (Aneides aeneus) (n = 60) tracked in Bankhead National Forest, northern Alabama, 2015–16.
Total overnight distance moved vs. net distance moved by Green Salamanders (Aneides aeneus) (n = 19; females = open points, males = closed points) tracked in Bankhead National Forest, northern Alabama, 2016.
Box and whiskers plot of ambient air, crevice air, and external body temperatures (°C) upon capture of Green Salamanders (Aneides aeneus) (n = 44) in Bankhead National Forest, 2015–16.
Linear regression of total overnight movement distance (m, square-root transformed) on size (snout–vent length [SVL] in mm) for adult female (open points, dashed line; n = 27) and male (closed points, solid line; n = 33) Green Salamanders (Aneides aeneus) tracked in Bankhead National Forest, northern Alabama, during 2015–16.
Linear regression of wandering ratio on size (snout–vent length [SVL]) for Green Salamanders (Aneides aeneus) (n = 19; females = open points, males = closed points) tracked in Bankhead National Forest, northern Alabama, during 2016. Envelope shows 95% confidence bands.
Contributor Notes
