HR: 0800h
AN: GC41A-0118    [Abstracts]
TI: Alpine Meadows Vegetation Monitoring
AU: Ababneh, L
EM: lababneh@wm.edu
AF: Visiting Assistant Professor, College of William and Mary Department of Geology P.O. Box 8795, Williamsburg, VA 23187, United States
AU: * Woolfenden, W
EM: paleotoon@gmail.com
AF: Mountain Heritage Associate, Retiree, USDA Forest Service 120 Wilson Rd, Bishop, CA 93514, United States
AB: East Shield (3658 m) and Barcroft Gate (3697 m) Meadows in the White Mountains of California on the Inyo National Forest were selected for a pilot study to provide quantitative descriptions of vegetation associations as a baseline for monitoring vegetation change over time. The study is part of the Global Observation Research Initiative in Alpine Environments Project (GLORIA) hosted by the University of California White Mountain Research Station. Separating the effect of climate change from anthropogenic disturbance is an integral step towards quantifying vegetation change in alpine meadows under current scenarios of future increases in global temperature and atmospheric carbon dioxide. In this study we compare the vegetation of East Shield Meadow, which is undisturbed, and Barcroft Gate Meadow, which is disturbed. Both are sedge-rush-grass wet meadows which are sustained by surface water in the form of streams and springs. The objective is to monitor fluctuations in vegetation, especially changes in species diversity and composition over five year time increments, along with tracking annual variations in precipitation. A comprehensive plant list was compiled and the dense vegetation of each meadow was sampled with a point intercept method along north-south and east-west randomly placed transects. The occurrence of all species at predetermined one-meter interval sample points along the transect were recorded, and percent occurrence was calculated. Twenty seven species of plants in Barcroft Gate Meadow and twenty four in East Shield Meadow were recorded, and sixteen species in Barcroft Gate Meadow and eight in East Shield Meadow were sampled. The 2007 IPCC report estimates that a doubling of atmospheric CO2 will increase global temperature within a possible range from 2.0 °C to 4.5 °C, with a best estimate of 3.0 °C. Assuming that the present general lapse rate of -6.32 °C per kilometer for the White Mountains will persist, a 3.0 °C increase may result in an equivalent elevation of about +475 m. Plots of elevation ranges of recorded species indicate that it is not likely that the projected temperature increase will affect the present distribution of the meadow plants. Species composition may change to an unknown degree, however, due to the possible increase in the abundance of those plants now at their upper elevation range limits in the meadows and to the upslope migration of plants whose upper ranges are now at lower elevations. Uncertainties in this projection include the behavior of meadow plants, adequate sampling of their species ranges, and future distribution of precipitation. Monitoring will reduce the uncertainties and confirm or correct the expected consequences of temperature change.
DE: 1600 GLOBAL CHANGE
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting