Semiarid hillslope processes

Semiarid environments show specific hydrological responses and geomorphological processes. Semiarid environments are characterized by dry conditions that do not allow for a full but, instead, only for a partial vegetation cover. The vegetation cover is generally patterned in a heterogeneous mosaic of vegetation patches and bare interpatches. This pattern highly influences geomorphologic processes on semiarid hillslopes. These patterns are not static, and a mutual interaction exists between geomorphologic processes and vegetation. At the bare interpatches, runoff is generated, and water is infiltrated into the vegetated areas.

The spatial patterns of the bare patches, as well as the variation in the bare surface conditions (such as initial soil-moisture conditions, slope length and angle, crust types, and rock fragment cover), determine their geomorphic response. On the other hand, the vegetation pattern and density determines the connectivity, runoff, and geomorphologic response at the hillslope scale. Changes in these patterns because of land-use change, grazing, or climate change will affect the vegetation cover pattern and hence connectivity and the geomorphologic response as expressed by erosion and sedimentation patterns at the hillslope.