Soil Biota in Banded Landscapes

Abstract

Patterned landscapes are characterized by the banding of perennial, usually dense vegetation on the contour, separated from more-or-less unvegetated soil. The vegetated section acts as a sink area, sequestering soil sediments, water, and nutrients shed from the bare source area immediately above it in the landscape. Water avail-ability is the driving force in patterned landscapes, controlling the structure and the dynamics of the vegetation. Runoff generated on the source zones is trapped on the upslope areas of the sink zones where infiltration proceeds. At the same time, erosion of the lower surface of the vegetated zone is occurring so that the vegetated band gradually moves upslope (Ambouta 1984; Thièry, d'Herbés, and Valentin 1995). Given the importance of overland flow in the formation and maintenance of patterned vegetation, it follows that factors that influence the amounts and distribution of runoff and infiltration will ultimately affect the patterning phenomenon itself.