Initial juvenile movement of pond-breeding amphibians in altered forest habitat

Abstract

The initial juvenile movement phase represents the first stage of the multi-phase process of natal dispersal. My objective was to investigate how alterations in forest habitat quality impact initial juvenile movement success and behavior. I conducted a mark-recapture study of juvenile Spotted Salamanders (Ambystoma maculatum) and Green Frogs (Lithobates clamitans) within experimental forest arrays. Spotted Salamander movement success was significantly greater in partial-cut treatments than the control or clearcut treatments. Green Frog movement success was greatest in the control forest. A greater proportion of both Spotted Salamander and Green Frog juveniles, initially moving through open-canopy habitats, redirected their movements toward forests. I next sought to identify how fine-scale habitat quality affects juveniles' decisions to cease moving away from their natal pond and settle. By using experimental enclosures, I attempted to isolate the effects of forest canopy and microhabitat manipulations on salamander settling decisions relative to unmanipulated forest controls. For Spotted Salamanders and Ringed Salamanders (A. annulatum) settling probability decreased with forest canopy removal and compacted soils. Spotted salamander settling probability increased with higher refuge densities.