9629723 GOLDBERG This research will examine the effects of competition among plant for limited resources such as light and water at the level of the entire community. While competitive effects on individual plant performance are well known, the general effects of competition on diverse and complex communities are much more poorly understood. Using desert annual plant communities as a model system, we will conduct a series of garden and field experiments to manipulate the density of entire plant communities to determine how competitive interactions lead to change in species' abundances and biodiversity. The experiments will mimic a natural rainfall gradient from a desert to a much wetter Mediterranean climate so that we can also investigate how the influence of competition changes among environments. Because models of global climatic change predict major shifts in precipitation patterns, these data are directly relevant to general models of how vegetation will respond to global environmental change.
