Modelling spatial aspects of plant-animal interactions.

Abstract

AbstractThe processes and mechanisms that determine spatial grazing behaviour are reviewed with reference to studies with sheep and steers grazing sown grasses, forages and rangelands. Spatial pattern, heterogeneity and their relevance in the grazing process; biodiversity, stability and the spatial pattern of plant communities; necessary elements for a comprehensive spatial model of grazing; a conceptual model of plant-animal interactions; and preliminary applications of the conceptual model to grazing management are discussed. Several conclusions are drawn. Realistic models of plant-animal interactions must include consideration of the reciprocal feedback between the spatial pattern of the plant community and the spatial pattern of herbivory. The stability, productivity and invasibility of plant communities under grazing disturbances should depend on the scale of heterogeneity and spatial pattern of disturbances. The defoliation pattern and degree of herbivore selectivity should depend on the scale and degree of vegetational heterogeneity relative to animal size. Large herbivores have complex abilities to respond to food spatial and temporal patterns at multiple scales. Spatial patterns of herbivory may be modified by manipulation of the spatial and temporal distribution of food rewards at multiple scales.