Diversity and similarity

Abstract Determining how many species are present in a particular habitat, their abundance, their importance, and how communities are related are critical questions in ecology and conservation biology. Ecologists use measures of diversity and similarity to understand community structure and function, particularly in terms of habitat use, food webs, predator–prey relationships, estimating how many species can co-exist within a community, energy flow, and nutrient cycling. Conservation biologists need to estimate diversity to identify areas for protection and management (Scott et al. 1987; Snodgrass et al. 2000), and to assess the effects of habitat change through time. Knowledge of these variables also is very practical for consultants or others doing rapid assessments, such as in the preparation of environmental impact assessments. Species diversity (richness, heterogeneity, evenness) is fairly simple to estimate, yet the use of these indices in amphibian studies is generally less than in many other areas of field research, and most field amphibian researchers have yet to explore the utility of measures of similarity.