CONICET | Buscador de Institutos y Recursos Humanos

We studied the effect of livestock grazing on the density of a Geoffroys cat (Leopardus geoffroyi) population in a semiarid scrubland of Argentina by comparing density estimates obtained during camera-trapping surveys in a protected area and in nearby cattle ranches in 2007-2008. We compared these results with those obtained during a camera-trapping study performed in the protected area in 2006. Overall, we obtained 247 pictures of Geoffroys cats. Capture success in the park was 9.08 and 6.09 records per 100 trap-days in 2006 and 20072008, respectively, whereas in ranches it was 1.70 records per 100 trap-days. Geoffroys cat densities (mean ± SE) at the park ranged from 13.9 ± 2.2 to 31.5 ± 8.0 individuals per 10 km2, depending on the buffer applied, whereas density estimates at ranches were on average 55% lower. Only 11% of the Geoffroy´s cats identified in 2006 could be still detected in the area two years later, indicating that there was a high turnover of individuals in this population. The sex ratios (M:F) estimated during both surveys at the park were 1:1.41 and 1:1.43, whereas at the ranches it was 1:0.75. Although crude numbers indicate a high proportion of Geoffroy´s cat males in ranches, the low number of individuals recorded precludes the possibility of assessing if differences in the sex ratio among areas were significant. Capture success of sympatric pampas cats (Leopardus colocolo) and jaguarundis (Puma yagouaroundi) was <0.30 records per 100 trap-days, and no evidence of these species was collected in the ranches. The numerical response of Geoffroys cat in ranches could be largely the result of human persecution and the effects of livestock on the habitat structure and on the prey base. Geoffroy´s cats seem to be tolerant to some degree of habitat alteration produced by livestock management.

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