The impact of herd composition and foraging area on livestock predation by big cats in the Pantanal of Brazil

摘要

The conflict caused by large carnivore attacks on livestock constitutes a major threat to the conservation of carnivore species worldwide. The objective of this study was to determine what factors influence jaguar Panthera onca and puma Puma concolor attacks on cattle at a ranch in the Brazilian Pantanal. Cattle herds were monitored for 57 months, and data were collected for each recorded mortality event. The economic impact of predation was calculated. We parameterize a generalized linear model with negative binomial error distribution to model the influence of water levels of the Paraguay River, size of cattle herd and the age structure of the herd on the monthly number of cattle killed by big cats. Over half of all recorded herd mortality events were caused by large cat predation, resulting in a maximum 2.83% of the average annual herd size and representing an annual financial loss of US$22 400.00. A positive relationship was found between the frequency of monthly attacks and the water level of the Paraguay River, whereas a negative relationship was found between monthly attacks and proportion of adult cattle in the herd. Juveniles were taken more frequently than adults. Increased water levels caused the herd to concentrate on higher ground usually near forested areas, suggesting an increase in cattle vulnerability to predation. A greater proportion of adults in the herd may also increase the possibility for defensive behavior, likely resulting in greater protection of younger cattle. Understanding the factors that predispose cattle to predation by big cats contributes to the establishment of management strategies that may reduce losses and, ultimately, conflict.