Climate change implications for sagebrush ecosystems.
Neilson, Ronald*,1, Lenihan, James1, Bachelet, Dominique2, 1 USDA Forest Service, Corvallis, Oregon2 Oregon State University, Corvallis, Oregon
ABSTRACT- Future climate scenarios universally indicate large changes ahead for the Great Basin Ecosystems. Increases in temperature are relatively certain and could produce a significant change in the frost regime. Changes in precipitation are more variable among future scenarios, with most showing large increases across the Basin, but a few newer scenarios showing more drought stress. The Great Basin is uniquely separated from the Southwest desert ecosystems in large part by the deep and regular annual frost regime. The Southwest desert ecosystems are far more diverse in part due to the more inconsistent frost patterns from year to year. This frost line is currently positioned on the elevational scarp that separates the lower Southwest deserts from the Basin. Warming could shift that frost line up into the Basin, allowing the frost line to shift far to the north. Such a shift would allow a great deal of Southwest diversity to invade the Basin, possibly displacing much of the Sagebrush ecosystem with a wide diversity of woodland and grassland ecosystems. Fire would increase as woody expansion is enhanced by increased precipitation. There would be lags in migration of new species, but in the meantime, existing species relative dominances could shift dramatically, as well as the physiognomic structure of existing communities.
Key words: sagebrush ecosystem, fire disturbance, climate change, great basin
All materials copyright The Ecological Society of America (ESA), and may not be used without written permission.