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ELUCIDATING THE MECHANISMS BEHIND SUCCESSFUL INDICATORS OF BIODIVERSITY
Citation:
Lawler, J. J., R D. White, AND L. L. Master. ELUCIDATING THE MECHANISMS BEHIND SUCCESSFUL INDICATORS OF BIODIVERSITY. Presented at International Association for Landscape Ecology, Darwin, Australia, July 12-17, 2003.
Description:
Groups of species have been proposed as indicators of biodiversity for use in conservation planning. Different tests of indicator groups have produced divergent results varying with taxonomy, methodology, scale, and location. At large scales, successful indicator groups should be composed of species with small non-overlapping ranges occupying different environments. We investigated these predictions with a database of occurrences of 920 species over an area of 317,000-km2 in the eastern United States. First, we randomly selected sets of species and tested their ability to act as indicators of biodiversity for selecting reserves to protect all species. We then compared indicator group composition with performance. Second, we used a stochastic optimization technique to identify sets of species that performed particularly well as indicator groups. Performance was associated with the area and compaction of species' ranges (r2 = 0.40). Optimally selected indicator groups were composed of rare species from several different taxa. Sites selected to protect these species covered a more diverse set of environments than those selected to protect the randomly chosen indicators. We conclude that indicator performance can be linked to simple aspects of species distributions, and that carefully chosen environmental surrogates may be a useful alternative to indicator species.