PARENT SESSION
Poster Session # 11: Disturbance Ecology.

Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Comparative measurements of wind and water erosion in semiarid grassland, shrubland, and forest ecosystems.

Johansen, Mathew^{*,1, 2}, Breshears, David³, Whicker, Jeffrey³, Pinder, John², ¹ Department of Energy, Los Alamos Area Organization, Los Alamos, NM² Colorado State University, Fort Collins, CO³ Los Alamos National Laboratory, Los Alamos, NM

ABSTRACT- Wind erosion is viewed as an important process in dryland ecosystems, yet measurements are lacking, especially for dryland grasslands and forests, as are consistently obtained estimates for cross-ecosystem comparisons. Further, erosion can result from both wind and water, yet measurement-based estimates of both processes within the same ecosystem are lacking. Here we compare wind and water erosion rates from three different semiarid ecosystem types: a shrubland near Carlsbad, New Mexico, a grassland near Denver, Colorado, and a forest near Los Alamos, New Mexico. In addition, we propose a framework for comparing the horizontal transport due to wind- and water-erosion. We used field measurements of wind erosion, rainfall simulations, and extrapolation methods to compare the two types of erosion within and among ecosystems. We found that wind erosion exceeded water erosion at the shrubland and forest sites, but not the grassland site, where the high clay content of the soils contributed to greater amounts of water erosion. Horizontal transport by wind was greater than that by water for all three systems, overwhelmingly so in the shrubland. Horizontal transport by wind exceed vertical transport by wind by more than an order of magnitude in all three systems. Our results, which include some of the only wind erosion measurements to date for semiarid grassland and forests, provide a basis for hypothesizing trends in wind and water erosion among ecosystems, highlight the importance of wind erosion in semiarid ecosystems, and have implications for land surface geomorphology, contaminant transport, and ecosystem biogeochemistry.

Key words: water erosion, biochemistry, wind erosion, semiarid ecosystems