Modifying landscape connectivity by reducing wind driven sediment redistribution, Northern Chihuahuan Desert, USA

Abstract

Shrub encroachment into perennial grasslands is occurring in many arid parts of the world. As shrubs dis- place perennial grasslands, bare patches can coalesce creating sediment transport pathways that further enhance sediment fluxes by wind transport. Reducing the connectedness of these pathways could slow or stop grassland loss by limiting sediment redistribution. To test this hypothesis, sediment retention struc- tures, hereafter called ''Connectivity Modifiers'' (Con-Mods), were placed in bare gaps of existing shrub- lands to block sediment movement by wind transport on two sites: the basin floor and a bajada (i.e. piedmont slope) at the Jornada Basin LTER in southern New Mexico. Wind blown sediment collectors and short-lived radionuclides ( 210 Pbex, 137 Cs, and 7 Be) were used to determine if these structures are affecting seasonal aeolian sediment transport within bare gaps. Net sediment flux rates at 10 cm height