9419640 Ostfeld A critical role for ecologists is to predict the consequences of perturbations to communities of interacting species. Traditional approaches to understanding the determinants of community structure and dynamics have focused on direct effects of populations on other populations and have ignored indirect effects. The PI's will begin to test the importance of both direct and indirect interactions in oak forest of southeastern New York state. Specifically, episodic mast production by oak trees stimulates a series of direct and indirect effects by causing transient increases in the density of rodent populations, and changes in space use by deer. Rodents, in turn, appear to be key regulators of low-density gypsy moth populations, and are the primary reservoirs for the etiological agent of Lyme Disease. White-tailed deer are the primary host for adult deer ticks, the vectors of Lyme Disease. The purpose of this project will be to demonstrate the effects of mast years on rodent population dynamics in oak forests. This will be tested with a large scale field experiment in which acorns are added to or removed from replicated 2.25 ha plots. Rodent populations will be monitored for one year. %%% This is an award that is designed to demonstrate the feasibility of the large scale acorn manipulation experiment, and to determine if rodent populations respond to the manipulation as predicted. Such information will provide the first step in understanding the direct and indirect effects of acorn production in deciduous forest landscapes.
