No abstract

Most large carnivore species are in global decline. Conflicts with people, particularly over depredation on small and large livestock, is one of the major causes of this decline. Along tropical deforestation frontiers, large felids often shift from natural to livestock prey because of their increased proximity to human agriculture, thus increasing the likelihood of conflicts with humans. On the basis of data from 236 cattle ranches, we describe levels of depredation by jaguars Panthera onca and pumas Puma concolor on bovine herd stocks and examine the effects of both landscape structure and cattle management on the spatial patterns and levels of predation in a highly fragmented forest landscape of southern Brazilian Amazonia. Generalized linear models showed that landscape variables, including proportion of forest area remaining and distance to the nearest riparian forest corridor, were key positive and negative determinants of predation events, respectively. We detected clear peaks of depredation during the peak calving period at the end of the dry season. Bovine herd size and proportion of forest area had positive effects on predation rates in 60 cattle ranches investigated in more detail. On the other hand, distance from the nearest riparian forest corridor was negatively correlated with the number of cattle predated. The mean proportion of cattle lost to large felids in 24 months for the region varied according to the herd class size (o500: 0.82%; 500-1500: 1.24%; 41500: 0.26%) but was never greater than 1.24%. The highest annual monetary costs were detected in large cattle ranches (41500 head of cattle), reaching US$ 885.40. Patterns of depredation can be explained by a combination of landscape and livestock management variables such as proportion of forest area, distance to the nearest riparian corridor, annual calving peak and bovine herd size.

Few researchers have investigated the synergistic effects of tropical forest fragmentation and disturbance on species persistence and abundance. We examined effects of both forest-patch metrics and forest disturbance in determining richness and abundance of midsized to large-bodied mammal species in a highly fragmented Amazonian forest landscape. Twenty-one forest fragments, ranging from 2 to 14,480 ha, and two continuous forest sites were sampled based on sightings, tracks, line-transect censuses, armadillo burrow censuses, and camera trapping. Patch occupancy of 37 species recorded ranged from 4% to all forest sites surveyed. Forest fragment size was the strongest predictor of species persistence, explaining 90% of the variation in species richness. Information-theoretic analysis confirmed that fragment area was the most important explanatory variable for the overall species richness and abundance of mammal species, followed by surface fires, which affected the abundance of seven species. Large mammal species were typically absent from fragments <100 ha, whereas some ubiquitous species were favored by fragmentation, exhibiting hyperabundance in small patches. Our findings highlight the importance of large (>10,000 ha), relatively undisturbed forest patches to maximize persistence and maintain baseline abundances of Neotropical forest mammal species.