Understanding Community and Ecosystem Responses to Interacting Global ChangesEPA Grant Number: U915538
Title: Understanding Community and Ecosystem Responses to Interacting Global Changes
Investigators: Zavaleta, Erika S.
Institution: Stanford University
EPA Project Officer: Jones, Brandon
Project Period: September 1, 1999 through September 30, 2001
Project Amount: $90,000
RFA: STAR Graduate Fellowships (1999) RFA Text | Recipients Lists
Research Category: Fellowship - Terrestrial Ecology and Ecosystems , Academic Fellowships , Ecological Indicators/Assessment/Restoration
The objectives of this research project are to: (1) understand the impacts of co-occurring climate and atmospheric changes on natural plant communities; (2) examine the long-term implications of global community changes for ecosystem processes, including carbon, nutrient, and hydrological cycles and productivity; and (3) develop a general framework for predicting the community and ecosystem responses to climate and atmospheric changes.
A combination of approaches are being used to study global-change impacts on community composition and structure in a California grassland-shrub ecosystem. For 2 years, I have worked with colleagues to monitor overall community composition and biomass responses, and the success of invading shrubs (Baccharis pilularisssp. consanguinea) in 136 grassland plots subjected to all possible combinations of four global changes: 2 degrees of warming, doubling of preindustrial levels of atmospheric CO2, 50-percent increases in rainfall, and a degree atmospheric nitrogen deposition typical of urban areas. To understand the longer term ecosystem consequences of the most significant change—shrub invasion of grasslands—I am examining the time course of change in ecosystem properties along an age gradient of shrub-invaded sites, ranging from 4 to 35 years postinvasion.