Landscape pattern metrics

Landscape ecology, if not ecology in general, is largely founded on the notion that environmental patterns strongly influence ecological processes [1, 2]. The habitats in which organisms live, for example, are spatially structured at a number of scales, and these patterns interact with organism perception and behavior to drive the higher level processes of population dynamics and community structure [3]. Anthropogenic activities (e.g., roads, development, and timber harvest) can disrupt the structural integrity of landscapes and is expected to impede, or in some cases facilitate, ecological flows (e.g., movement of organisms) across the landscape [4]. A disruption in landscape patterns may therefore compromise its functional integrity by interfering with critical ecological processes necessary for population persistence and the maintenance of biodiversity and ecosystem health [5]. For these and other reasons, much emphasis has been placed on developing methods to quantify landscape patterns, which is considered a prerequisite to the study of pattern–process relationships (e.g., Refs 6–10). This has resulted in the development of literally hundreds of indices of landscape patterns. This progress has been facilitated by recent advances in computer processing and geographic information (GIS) technologies. Unfortunately, according to Gustafson [11], “the distinction between what can be mapped and measured and the patterns that are ecologically relevant to the phenomenon under investigation or management is sometimes blurred.” The purpose of this article is to provide an overview of landscape pattern metrics and their use and limitations in landscape ecology. Note, herein we use the terms “landscape pattern” and “landscape structure” synonymously to reflect common usage in the literature.