9725937 Levin Support for this project will enable American researchers to collaborate with and benefit from researchers and facilities at the Center for Ecological Research at Kyoto University in Japan and the Center for Population Biology at the Imperial College in the United Kingdom. The impact of environmental variability and competitive exclusion on the number of species required to maintain a certain level of function in communities will be determined mathematically. Those relationships will then be tested in a series of experiments in which species numbers and environments are manipulated. The U.S. team will be primarily responsible for the derivation of the theoretical diversity-function relationships, and will, in cooperation with the U.K. team, conduct field experiments in which species number, precipitation, and herbivory are manipulated. The Japanese team will perform growth-chamber experiments on communities subjected to different levels of predation or parasitism. Many current analyses of ecological diversity-function relationships ignore variations in the performance of individual species with varying environmental conditions, and ignore the impacts of competitive exclusion on multi- year measures of community function. This project will combine the expertise and facilities of American, Japanese and British research groups to investigate the level of biodiversity preservation required to maintain essential ecosystem services and functions. ***
