Habitat Correlates of the Del Norte Salamander, Plethodon elongatus (Caudata: Plethodontidae), in Northwestern California

Abstract

A stratified systematic sampling design was used to quantify the habitat relationships of the Del Norte salamander (Plethodon elongatus) in northwestern California. We sampled 57 sites, each within at least 5-7 ha of relatively homogeneous forest or post-forest habitat, where we measured 83 characteristics of the environment. Salamander sampling consisted of area-constrained sampling of 7 x 7 m plots with at least 25% rock cover at each site. A subset of 43 variables was used in a hierarchical analysis of habitat associations using discriminant analysis and regression. Variables included attributes at the landscape, macrohabitat, and microhabitat scales. Results indicate a significant association of the Del Norte salamander with older forests with closed, multi-storied canopy (composed of both conifers and hard- woods), with a cool, moist microclimate, and rocky substrates dominated by cobble-sized pieces. These habitat attributes appear optimal for survival and reproductive success throughout most of the range of this species. The Del Norte salamander may require ecological conditions found primarily in late seral stage forests.