PATCH STRUCTURE IN TALLGRASS PRAIRIES - DYNAMICS OF SATELLITE SPECIES

Space in tallgrass prairie communities is dominated by a few core species. A large number of less abundant, satellite species occupy the remaining space, defining vegetation patches that vary within and between growing seasons. Five permanent 100-m2 blocks were established in undisturbed tallgrass prairie in Oklahoma and Kansas. Characteristics of patch structure included number of patch types, patch type diversity, patch composition, number of spatial groups, group size, and fractal dimension of the spatial groups. Actual patch structure, defined mainly by satellite species, was not significantly different from simulated patch structure, except that simulated patches were more fragmented. Therefore, processes that affect species associations may not be important controls of patch structure of satellite species within the spatial and temporal scale of this analysis. Dispersal processes may have significant effects on patch structure at this scale. In order to understand grassland community dynamics, satellite species should be modelled using stochastic models constrained by core species dynamics. -from Authors