2008 Joint Annual Meeting (5-9 Oct. 2008): The Effects of Land Use and Climate Change on the Erodibility of Desert Soils

Dryland regions constitute over 35% of terrestrial lands around the globe. Limited rainfall in these regions restricts plant growth, and the spaces between vascular plants are often large. Most interspace soils are protected from wind erosion by the cover of rocks, physical crusts, and biological crusts (cyanobacteria, lichens, and mosses). However, disturbance of the soil surface in dryland regions (e.g., recreation, livestock, mining and energy exploration, military exercises, fire) reduces or eliminates the protective cover of the soils. The effects of future climate changes will also reduce cover of desert soil stabilizers such as plants, plant litter, and biological crusts, thus increasing dust production. Wind tunnel data show that most desert surfaces produce little sediment under typical wind speeds. However, disturbing the soil surface with vehicles, humans, or animals resulted in much higher sediment production from all surfaces tested, regardless of parent material, texture, or age of the soil surface. The largest changes in threshold friction velocity and sediment production occur when non-disturbed surfaces are first disturbed. Synergist effects, such as surface disturbance occurring during drought periods in annualized plant communities, can create very large dust events. As surface disturbance, invasion, and drought are expected to increase in the future, an increase in dust production can be expected as well.