Project Information

The field sites are located near Canyonlands National Park on the Colorado Plateau, a cold desert in southern Utah. The Colorado Plateau lies at the southern boundary of winter-storm systems and at the northern boundary of summer-monsoon systems, giving this region about equal amounts of precipitation in summer and in winter. Rainfall boundaries can shift under the influence of global climate change, causing changes in local precipitation patterns. Using the Colorado Plateau as a model system where the effects of shifting weather patterns should be experienced first, we investigate how changing precipitation patterns impact the species and the ecosystem fluxes of arid lands.

Earlier work established the plants of this region diversify in their relative utilization of summer and winter-derived soil moisture. Winter-derived soil moisture is stored in deeper soil layers and extracted by plants over the course of the warm season. Summer-derived soil moisture becomes available in the form of short pulses of soil moisture in the shallow soil. Root distribution and whole-plant transpiration capacity determine to what extend plants can benefit from brief summer showers.

Our overall goal is to examine the significance of spring and summer rainfall events in arid ecosystems, especially regarding their capacity to reduce water stress conditions in plants, influence soil nutrient turnover, contribute to primary productivity, and affect competitive interactions among plants.