Patchy Nitrogen Redistribution And Food Web Subsidies Caused By Deer Foraging In Multiple-Use Landscapes

University Of Maryland Center For Environmental Sciences, Cambridge MD

Investigators

Abstract

ABSTRACT The invertebrates that comprise the forest-floor food web use annual leaf fall for energy and nutrients. Thus the amount of energy and nutrients in leaf litter is believed to determine invertebrate and possibly vertebrate predator population sizes and reproduction. Where highly fertilized agricultural crops intermix with forest, large populations of white-tailed deer often feed on crops during the night and retreat to the forest for concealment during the day. By excreting nutrients in the forest, deer transport nutrient "subsidies" to the forest food web. Nitrogen transport is of particular interest because of its importance for terrestrial food webs and its impacts on forest health. This research addresses three primary questions: (1) How much nitrogen do deer transport into forests from agricultural land? (2) What conditions of land use result in the largest transports of nitrogen? and (3) What is the effect of nitrogen subsidies on the forest food web and forest-floor nitrogen cycling? These questions will be addressed by systematic field sampling of forest patches for nitrogen deposition and by tracking deer movements using global positioning system technology. A field experiment will be used to evaluate the impact of energy and nitrogen subsidies created by deer on the forest food web. Results of the research will aid in understanding the effect of human land-use on native forest ecosystems, provide new insight to the multi-faceted impacts of overabundant white-tailed deer on forest ecology, and advance understanding of the role that food web dynamics play in forest nutrient cycling