Ecohydrological interactions within banded vegetation in the northeastern Chihuahuan Desert, USA

Landscape patterns, consisting of alternating densely vegetated bands and sparsely vegetated interbands, occur in semi-arid and arid re,ions of Africa, Asia, Australia and North America. The structure of vegetation patterns has been well documented, but a wide array of underlying environmental factors and ecological processes have been suggested, with no consensus regarding the genesis and persistence of these patterns. The purpose of this study was to assess ecohydrological interactions within this banded pattern by quantifying reallocation of rainfall and soil sediments. Even subtle redistribution impacted plant biomass production and species composition. Although runoff losses from interbands accounted for only 4% total rainfall, reallocation supported tree species and bunchgrasses that would not be sustained if precipitation were evenly distributed. Additionally, a rainfall threshold was identified. When storm totals exceeded 16 mm, even the densely vegetated bands were unable to capture all the rainfall and run-on from the upslope, sodgrass interbands; a portion of the runoff from interbands flowed through the vegetated bands and continued downslope into the next interband. Copyright (C) 2008 John Wiley & Sons, Ltd.