Many habitats are a mixture of trees and grasses. These include prairies, savannas, and woodlands. These communities often shift in their balance of grasses and trees, with important consequences for both native biodiversity and humans (bush encroachment, rangeland production). However, the mechanisms underlying these changes are poorly understood, in part because trees and grasses can have both positive and negative effects on each other. For example, trees and grasses compete for water and light, but also can improve soil conditions and protect each other from herbivores. Large-scale, long-term experiments in an acacia savanna in Kenya will examine how tree-grass interactions, and savanna ecology in general, are effected by a) wild and domestic herbivores, b) tree size, and c) tree density. One of the goals of this research is to inform local stakeholders of the consequences of their land management practices. In many parts of the world, including the study area in Kenya, wildlife coexists with domestic cattle on mixed-use rangeland. An understanding of the effects of wild and domestic herbivores on tree-grass interactions is central to successful management of these rangelands for both production and conservation objectives. This project will keep regional land managers informed of its findings. Several informal workshops will be held with stakeholders to discuss their perceptions of historical changes in the area, to disseminate research results, and to discuss their management implications.
