A GIS model for identifying eastern spadefoot toad ( Scaphiopus holbrookii) habitat in eastern Connecticut

Abstract

The eastern spadefoot toad ( Scaphiopus holbrookii) is listed as endangered in Connecticut, having only one viable population in the state. Efforts to investigate their distribution in Connecticut are frustrated by their rarity, as well as their nocturnal and fossorial habits. The purpose of this study was to develop a geographic information systems (GIS) model to identify eastern spadefoot toad habitat in eastern Connecticut. Known eastern spadefoot toad sites in Connecticut, Massachusetts, and Rhode Island were used to establish the model’s selection criteria (i.e., substrate and elevation). Drainage class, texture class and soil deposit type within 250 meters of each site were summarized by acreage to reveal the predominant characteristics of the substrate. Digital elevation models (DEMs) were used to calculate relative elevation, expressing the absolute elevation as a percentage of the range in the surrounding landscape. Applying the selection criteria in eastern Connecticut produced a GIS shapefile of potential eastern spadefoot toad habitat. The results of verification analyses suggest that the eastern spadefoot toad habitat model (ESTHM) is a promising tool for identifying areas of eastern spadefoot toad habitat.