A CONCEPTUAL GENEALOGY OF FRAGMENTATION RESEARCH: FROM ISLAND BIOGEOGRAPHY TO LANDSCAPE ECOLOGY^*

Abstract

The concept of habitat fragmentation has become an important theme in conservation research, and it is often used as if fragmentation were a unitary phenomenon. However, the concept is ambiguous, and empirical studies demonstrate a wide variety of direct and indirect effects, sometimes with mutually opposing implications. The effects of fragmentation vary across organisms, habitat types, and geographic regions. Such a contrast between a schematic concept and multifaceted empirical reality is counterproductive. I analyzed the stabilization of the schematic view of fragmentation by the early 1980s, using a genealogical narrative as a methodological approach. The main assumptions behind the schematic view were: (1) fragments are comparable to oceanic islands; (2) habitats surrounding fragments are hostile to a majority of the organisms; and (3) natural pre-fragmentation conditions were uniform. The stabilization loop of this view was supported by the reduction of empirical research to species–area curve fitting, which always produced expected results. I present a model of the dynamics of fragmentation research that shows the schematic, island-biogeographic view as an “intellectual attractor.” Since the 1980s, the theoretical presuppositions of the schematic view have been challenged, and empirical research has become multifaceted. Fragments of a particular habitat type are viewed as elements in a heterogeneous landscape rather than “islands” surrounded by a hostile “sea.” However, the island metaphor is still used in conservation contexts in the shape of species–area curves. It is backed by a presupposition that human-influenced environments are essentially different from so-called “natural” environments, but this is unfounded. My suggestion is that our perspective should be broadened still further so that habitat fragmentation is viewed as a particular form of human-induced environmental degradation; I discuss both theoretical and practical implications of this suggestion.