Heterogeneous spatial distribution of traditional livestock settlements and their effects on vegetation cover in arid groundwater coupled ecosystems in the Monte Desert (Argentina)

Abstract

The growing population and land-use pressures in arid areas demands a better understanding of the interactions between humans and the environment. Patterns of human occupation are linked to natural resources, such as water and forest resources. In the Monte Desert, shallow groundwater sustains phreatophyte forests and extensive livestock settlements. This study aims to detect environmental factors (i.e., water availability, roads) that affect settlement distribution, estimate the area of influence of individual settlements on surrounding vegetation, and the impact of settlement densities on vegetation cover at a regional scale, using spatial analysis, remote sensing, and vegetation surveys. We found a heterogeneous and aggregated spatial distribution of settlements, with higher densities near rivers and an old-river bed. We detected vegetation changes associated with land-use with the spectral vegetation index SATVI (soil adjusted total vegetation index), which were not detected with NDVI and SAVI (normalized difference vegetation index and soil adjusted vegetation index, respectively). Vegetation was reduced within 2 km of settlements, outside a fenced reserve, and in areas with high settlement densities. Our study suggests that future changes on water availability may affect livestock settlement spatial distribution, densities, and vegetation, pointing to the need of integrated land-use management.