Las actividades antrópicas determinan la conectividad del paisaje para los guanacos Lama guanicoe en Patagonia norte

WALKER, S.; NOVARO, A.; FUNES, M.; PUIG, S.; CARMANCHAHI, P.; VIDELA, F. ; RADOVANI, N.; DIDIER, K.

Bariloche

Jornada; III Jornadas Argentinas de Ecologia de Paisajes; 2011

Guanacos in northern Patagonia have suffered a decline of greater than 90% over the last 30 years. Populations of guanacos are mostly small and isolated, in spite of the fact that habitat structure is largely intact. Unlike in forested habitats where habitat fragments and corridors of remnant habitat are easily identifiable, in arid environments such as the Patagonian steppe, landscape connectivity is not defined by changes in habitat structure. Our objective was to identify patterns of landscape connectivity for guanacos in the northern Patagonian steppe and scrub. As guanacos were widely distributed in the past, we hypothesized that fragmentation of populations today is a result of the distribution and intensity of human activities. We obtained DNA samples from carcasses and captured guanacos at five sites in northern Patagonia (Mendoza, Neuquén, and Río Negro provinces) and analyzed 10 microsatellite loci to calculate genetic distances among these populations. We ranked each cell in a 10 X 10 km grid in terms of current presence and abundance of guanacos based on surveys and interviews with provincial wildlife rangers, and presence and intensity of human activities, determined from satellite images, available GIS databases, and expert opinion. We assigned friction values based on the ranking of each cell from 1 for areas with currently large populations of guanacos to 10,000 for urban or other areas that act as complete barriers to guanaco movements. We measured Euclidean distance and calculated cost distance based on the friction map among all sites and did a Mantel regression between genetic distance and both Euclidean and cost distances. Genetic distances among populations were not significantly correlated to Euclidean distances (p = 0.18), but were correlated to cost distances (p = 0.05). We conclude that landscape connectivity for guanacos in northern Patagonia can be defined by the distribution and intensity of human activities.