Masters Thesis

A mark-recapture study of the wandering salamander, Aneides vagrans, in a redwood rain forest canopy

I investigated seasonal activity, movement patterns, and habitat use of the wandering salamander, Aneides vagrans, in an old-growth forest canopy. During the fall and winter months from September 2000 to January 2003, a mark—recapture study of salamanders was conducted in the crowns of five large redwoods (Sequoia sempervirens) in Prairie Creek Redwoods State Park, Humboldt County, California. This represents a first attempt to describe the arboreal behavior of A. vagrans. A cover object approach limited damage to fragile canopy habitats. Litter bags were placed on 65 randomly selected fern mats, covering 10% of the total surface area of epiphytic fern (Polypodium scouleri) mats in each tree. Crack boards were also placed on one fern mat in each of two trees. These cover objects were then checked 2-4 times per month during the field season. Captured salamanders were marked by injecting tags near the base of the tail. A total of 52 captures were made of 40 individuals, including 15 recaptures. One salamander was captured on 4 occasions over the 3-year study period. Only one recaptured salamander moved (vertically 7 m) from its original point of capture. There was no evidence of territorial behavior by A. vagrans in the canopy. Salamander captures were compared to tree-level and fern mat-level variables with correlation analysis and stepwise regression. At the tree-level, the best predictor of salamander abundance was the total mass of fern mats in crotches. At the fern mat-level, the presence of crack boards accounted for 85% of the variability observed in captures, while the mass and height of the fern mat accounted for the remaining 6% explained by the model. Population estimates were made by applying the Lincoln-Peterson method to the capture data. This analysis revealed that individual redwoods can support at least 28 individual salamanders associated with fern mats. By virtue of their high water-holding capacities, large fern mats likely enable year-round occupation of the redwood forest canopy by A. vagrans. Anecdotal observations of A. vagrans and its close relative A. ferreus by scientists and forest activists strongly suggest that these salamanders also occupy additional habitats in forest canopies, especially rotting wood and fire cavities.