Funded Research Projects: WILDLIFE SCIENCE

Collaborative Research: Interactive Effects of Climate Change, Ecosystem Engineering, and Tropic Interactions on Grassland Community Dynamics

Research Sponsored By: National Science Foundation (NSF)
Principal Investigator: Laura Prugh
Project Description
The goal of this study is to determine how the trophic and engineering effects of consumers affect plant communities under differing climatic conditions. Small mammals can strongly affect plant communities via both top-down (e.g., seed predation and herbivory) and bottom-up forces (e.g., soil disturbance and nutrient deposition). We hypothesize that these biotic interactions may reduce or amplify the effects of climate change on plant communities, depending on whether plant responses to biotic interactions oppose or are synergistic with their responses to changed resource availability. Specifically, keystone seed predation by granivores should prevent plants that benefit from altered precipitation patterns from outcompeting plants that perform poorly under novel climatic conditions. Conversely, soil disturbance from burrowing mammals should amplify the effects of precipitation, for example by further enhancing the competitive ability of invasive grasses. These and other hypotheses will be tested by adding precipitation manipulations to an existing experimental study in the Carrizo Plain National Monument, CA. For the past seven years, kangaroo rat exclosures have been used to examine interactions among giant kangaroo rats (Dipodomys ingens), plants, invertebrates, and other vertebrates in an endangered grassland community. As the first study to experimentally manipulate both small mammal abundance and climatic conditions, this project will provide novel insights into the bottom-up and top-down effects of consumers, illuminating how these effects interact with climate. Findings of this study will improve management of endangered and invasive species in the Carrizo Plain, the last major remnant of San Joaquin grasslands and a hotspot of endangerment.