The spatial configuration of vegetation as an indicator of landscape degradation due to livestock enterprises in Argentina.
The spatial configuration characteristics of vegetation were studied in the Los Alerces National Park (LANP) in order to develop ecological indicators of landscape degradation produced by livestock-related activities in Argentine subantarctic forest. The study site contained 5 main vegetation types, comprising evergreen or deciduous 'high' or 'low' forests, and grasslands. Two indices were devised. One, the 'D' index, was designed to express the variations in the vegetation types as related to the area occupied by each, the area-perimeter ratio, and the configuration regularity. The D index enabled determination of the degradation stage of different vegetation types, and the past and recent impact of livestock in a given area, providing some significant effects at landscape level could be detected. The second index, the 'V' index, summarizes field information such as cover of annual species, cover of exotic species, cover of Rumex acetosella, total biomass and clonal biomass. This index was designed to evaluate the aptitude of the D index to monitor landscape degradation. The identification and distribution of areas at risk, at a regional scale, facilitates the detection of those rural settlements that pose an imminent or potential hazard to the conservation of forest resources and require urgent changes in livestock management.