Using Relative Capacity to Measure Habitat Suitability

Abstract

Habitat suitability (HS) modeling relates a species' potential presence/absence to a set of environmental variables. Because of stochastic or demographic population fluctuations, relating abundance to environment is difficult and generally requires time-series of population-density data. Here, I propose an approach to compute relative capacity of a set of habitat classes. I defined relative capacity of a habitat class as being proportional to its carrying capacity, and replaced time-series of density measures with spatial replicates. A hypothetical environment was first divided into several habitat classes and population densities were measured in a sample of these habitats. Three methods of computing relative capacity were compared: (1) maximum density per habitat class, (2) coefficients of a Generalized Linear Model (GLM) of the habitat densities, and (3) slopes of isodars computed for all pairs of habitat classes. Accuracy of these methods was evaluated using spatially-explicit demographic simulations....