Landscape heterogeneity indices: problems of scale and applicability, with particular reference to animal habitat description

Faunal use of the landscape is considered, focussing on the case of birds in vegetation remnants in the Western Australian wheatbelt, and it is argued that attempting to describe landscape heterogeneity by a single heterogeneity index is inappropriate.

Abstract

Efforts to quantify landscape heterogeneity have resulted in the production of a large number of indices based on the number and proportions of different types of landscape (usually vegetation) patches. In this paper we question whether these indices provide useful tools with which to examine functional aspects of landscape heterogeneity. In particular, we consider faunal use of the landscape, focussing on the case of birds in vegetation remnants in the Western Australian wheatbelt. We argue that attempting to describe landscape heterogeneity by a single heterogeneity index is inappropriate, because the qualitative differences between patch types and their spatial relationships frequently cannot both be described by a single value. Also, scales of study have to match the scale of the processes in which we are interested, or the scale at which particular organisms perceive their environment. Generalized indices of landscape heterogeneity may therefore have little predictive capacity for detailed process or habitat studies.