PARENT SESSION
Oral Session #74: Spatial Ecology: Models and Methods. Presiding: C. Loehle.
Friday, August 10, 2001. 8:00 AM to 11:30 AM. Hall of Ideas E.
The fuzzy structure of biological groups.
Schaefer, James 1, Wilson, Chris2, 1 2
ABSTRACT- Defining organism groups is central to ecology. Conventional classification -- with its emphasis on all-or-nothing group membership -- has remained fundamentally detached, however, from the darwinian philosophy of biology. We used fuzzy cluster analysis, which allows for graded group membership, to examine the population structure of woodland caribou in Quebec-Labrador (based on spatial affinities), habitats selected by muskoxen in the High Arctic (based on ecological similarities), and taxonomy of Daphnia species in Australia (based on genetic dissimilarities). In each case, groups delineated by fuzzy classification were qualitatively similar to those from traditional cluster analysis. Fuzzy clustering, however, conveyed the vagueness of these biological assemblages, stemming from partial group affinities and hybridization. Because uncertainty of group identity may persist even with perfect knowledge, fuzzy classification appears widely applicable for delineating populations, habitats, species, and other entities fundamental to ecological study.
KEY WORDS: population delineation, species, habitats, vagueness