An ecological framework for contextualizing carnivore-livestock conflict.

Carnivore predation on livestock is a complex management and policy challenge, yet it is also intrinsically an ecological interaction between predators and prey. Human-wildlife interactions occur in socioecological systems in which human and environmental processes are closely linked. However, underlying human-wildlife conflict and key to unpacking its complexity are concrete and identifiable ecological mechanisms that lead to predation events. To better understand how ecological theory accords with interactions between wild predators and domestic prey, we developed a framework to describe ecological drivers of predation on livestock. We based this framework on foundational ecological theory and current research on interactions between predators and domestic prey. We used this framework to examine ecological mechanisms (e.g., density-mediated effects, behaviorally mediated effects, and optimal foraging theory) through which specific management interventions operate, and we analyzed the ecological determinants of failure and success of management interventions in 3 case studies: snow leopards (Panthera uncia), wolves (Canis lupus), and cougars (Puma concolor). The varied, context-dependent successes and failures of the management interventions in these case studies demonstrated the utility of using an ecological framework to ground research and management of carnivore-livestock conflict. Mitigation of human-wildlife conflict appears to require an understanding of how fundamental ecological theories work within domestic predator-prey systems.

Un Marco de Trabajo Ecológico para Contextualizar el Conflicto Carnívoro - Ganado Resumen La depredación del ganado por carnívoros es un reto complejo para el manejo y las políticas, a pesar de que es intrínsecamente una interacción ecológica entre depredadores y presas. Las interacciones entre humanos y la fauna ocurren en sistemas socio-ecológicos en los que los humanos y los procesos ambientales están conectados estrechamente. Sin embargo, el conflicto humano - fauna subyacente y la clave para desenredar su complejidad son mecanismos ecológicos complejos e identificables que resultan en eventos de depredación. Para tener un mejor entendimiento sobre cómo la teoría ecológica armoniza con las interacciones entre los depredadores silvestres y la presa doméstica, desarrollamos un marco de trabajo para describir las causantes ecológicas de la depredación del ganado. Basamos este marco de trabajo en las principales teorías ecológicas y las investigaciones actuales sobre las interacciones entre los depredadores y las presas domésticas. Usamos este marco de trabajo para examinar los mecanismos ecológicos (es decir, los efectos mediados por la densidad, los efectos mediados por el comportamiento, y la teoría del forrajeo óptimo) mediante los cuales operan ciertas intervenciones específicas de manejo y analizamos las determinantes ecológicas del fracaso y el éxito de las intervenciones de manejo en tres estudios de caso: el leopardo de las nieves (Panthera uncia), el lobo (Canis lupus), y el puma (Puma concolor). Los éxitos y fracasos variados y dependientes del contexto que sufrieron las intervenciones de manejo en estos estudios de caso demostraron la utilidad del uso de un marco de trabajo ecológico para aterrizar la investigación y el manejo del conflicto carnívoro - ganado. La mitigación del conflicto humano - fauna parece requerir de un entendimiento sobre cómo funcionan las teorías ecológicas fundamentales dentro del sistema doméstico depredador - presa.

Maximum weight capacity of leaves used by tent-roosting bats: implicatons for social structure

Fewer than 2% of bats can modify their environment to construct roosts. Tent-roosting bats cut and fold leaves to form roosts called tents. Unlike the caves or hollow trees used by some bats, leaves possess an upper limit on their capacity to support weight. We tested the hypothesis that the maximum weight capacity that leaves can support limits the maximum social group size of bats that roost in them. We conducted research in the Tirimbina Biological Reserve (TBR), Sarapiquí, Costa Rica, between March and April 2012. We added weight incrementally to new leaves of three plant species until the angle of the leaves fell below that which bats naturally use. Philodendron fragrantissimum and Heliconia imbricata support one-third more weight than Asterogyne martiana. This study demonstrates that the maximum weight that the leaves can support is similar to the mean social group weight of D. watsoni and Ectophylla alba reported in the literature for these plant species and lower than the maximum reported social group weights. Therefore, it is possible that the maximum weight capacity of the leaves used to construct roosts limits the maximum social group size.

Maximum weight capacity of leaves used by tent-roosting bats: implicatons for social structure

Fewer than 2% of bats can modify their environment to construct roosts. Tent-roosting bats cut and fold leaves to form roosts called tents. Unlike the caves or hollow trees used by some bats, leaves possess an upper limit on their capacity to support weight. We tested the hypothesis that the maximum weight capacity that leaves can support limits the maximum social group size of bats that roost in them. We conducted research in the Tirimbina Biological Reserve (TBR), Sarapiquí, Costa Rica, between March and April 2012. We added weight incrementally to new leaves of three plant species until the angle of the leaves fell below that which bats naturally use. Philodendron fragrantissimum and Heliconia imbricata support one-third more weight than Asterogyne martiana. This study demonstrates that the maximum weight that the leaves can support is similar to the mean social group weight of D. watsoni and Ectophylla alba reported in the literature for these plant species and lower than the maximum reported social group weights. Therefore, it is possible that the maximum weight capacity of the leaves used to construct roosts limits the maximum social group size.(AU)