Animals affect plant community structure and dynamics directly (consumption) and indirectly (physical disturbance). It is clear that in addition, the spatial pattern of impacts also significantly influences the structure of plant communities. This collaborative research project will test a series of hypotheses concerning the spatial patterns of herbivore influence using a system of animal-generated disturbances (plains pocket gophers in herbaceous plant communities) that occur in spatially predictable patterns (uniformly spaced burrows and aggregated mounds on the surface). The impact of the spatial pattern of disturbance on resource distribution and plant community structure will be investigated. Furthermore, these patterns will be analyzed at several scales (from microscale neighborhood effects to field-wide patterns). Comparisons also will be made between two sites that differ significantly in soil characteristics, allowing analysis of the amplitude of herbivore-generated effects in relation to soil fertility. This work will contribute significantly to understanding the role of animals in plant community structure by determining the patterns of animal activities and the mechanisms by which they are translated into pattern in the environment, in plant growth and recruitment, and in vegetation across spatial scales ranging from several cm2 to hundreds of m2.
