A HIERARCHICAL ANALYSIS OF SPECIES ABUNDANCE PATTERNS IN GRASSLAND VEGETATION

At the regional level, grassland data from sites in Oklahoma and Kansas conform to the general predictions of the core-satellite hypothesis. Patterns found on the scale of a local assemblage of species (m2), however, were similar to those of the regional-level distributions (km2). Factors affecting these distributions are competition and dispersal, which operate most commonly on small spatial scales, as well as disturbance, which is often a large-scale phenomenon in grasslands. Thus, grassland community structure exhibits self-similarity, in that the large-scale pattern is composed of numerous small scale units of similar structure. Grassland communities thus essentially exhibit small-scale patterns that are transposable to larger-scale patterns and vice versa, but the patterns of distribution and abundance are dramatically affected by disturbance, and changes in these patterns are most obvious on an intermediate (community-level) scale of analysis. -from Authors