Grantee Research Project Results
An Integrated Field Investigation of the Interactions Between Climate Change and Ecosystem Structure and FunctionEPA Grant Number: U915000
Title: An Integrated Field Investigation of the Interactions Between Climate Change and Ecosystem Structure and Function
Investigators: Dunne, Jennifer A.
Institution: University of California - Berkeley
EPA Project Officer: Packard, Benjamin H
Project Period: January 1, 1996 through January 1, 1999
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1996) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology
The objective of this research project is to compare and synthesize results from an ongoing ecosystem warming experiment with measurements of vegetation, nutrient, and microclimate dynamics 1) along a natural climatic gradient, and 2) within a new set of warming-related climate manipulations along the gradient. In particular, I am examining the interactions of climate warming and ecosystem structure and dynamics within an ecotone of Rocky Mountain subalpine meadow and Great Basin shrub steppe.
I am conducting research in subalpine meadows near the Rocky Mountain Biological Laboratory in the upper East River Valley of Gunnison County, CO. One site (the "warming meadow") was established in 1991, and has a set of five control plots and five manipulated plots with overhead heaters that increase downward IR flux as predicted under doubled CO2. The heaters result in earlier snowmelt, longer growing season, 1-2 degrees C soil warming, and 10-25% percent soil drying during the growing season. In 1995, I established three additional sites along an elevational gradient centered near the warming meadow. Each of the new sites has five control plots and five manipulated plots in which snowmelt is accelerated via shoveling. Timing of snowmelt differs naturally among the gradient sites to the degree that it differs between control and manipulated plots at each of the four sites (about 1-2 weeks). In each of the plots from 1996-1998, I monitored dynamics of the following parameters during the snow -free growing season (mid May to mid September): plant reproductive phenology; aboveground biomass of shrubs, forbs, and graminoids; plant community composition and shrub seedling establishment; and soil inorganic nitrogen stocks, in situ net nitrogen mineralization rates, and C:N ratios. In addition, each plot has soil moisture and temperature data sets that calculate year round and every 2 hours at 12 and 25 cm.