Mammals are threatened with population decline and extinction. Numerous species require immediate conservation intervention. But our ability to identify species on the brink of decline, and to intervene successfully, depends on developing reliable leading indicators of population, community, and environmental change. Classic approaches, such as population and life history assessment, as well as indicator species, trail environmental change. Adaptive behaviors honed by natural selection to respond quickly to environmental changes represent true leading indicators that we can learn to apply to conservation and management. Excellent examples of useful behaviors for conservation include foraging behavior, patch use, and habitat selection. Comparisons among giving-up densities collected in artificial resource patches can effectively indicate the forager's predation costs, its habitat quality, mechanisms of coexistence, and environmental richness. Patterns of adaptive habitat use can similarly reveal the relative value of different types of habitat, the location, and amounts of source versus sink habitat in a landscape, the effects of human disturbance, and projections on future extinction risk. Each behavior is likely to change more quickly than population size. As useful as these and related indicators may be to managers and conservationists, similar behaviors can emerge from different causes, and immediate returns of behavior to fitness may cause rapid evolution of associated morphological and physiological traits. Conservation strategies will thereby often be most effective if they build on research programs targeting the processes influencing adaptive behaviors and that assess whether wild-type or novel behaviors are most likely to sustain populations into the future.

Livestock populations in protected areas are viewed negatively because of their interaction with native ungulates through direct competition for food resources. However, livestock and native prey can also interact indirectly through their shared predator. Indirect interactions between two prey species occur when one prey modifies either the functional or numerical responses of a shared predator. This interaction is often manifested as negative effects (apparent competition) on one or both prey species through increased predation risk. But indirect interactions can also yield positive effects on a focal prey if the shared predator modifies its functional response toward increased consumption of an abundant and higher-quality alternative prey. Such a phenomenon between two prey species is underappreciated and overlooked in nature. Positive indirect effects can be expected to occur in livestock-dominated wildlife reserves containing large carnivores. We searched for such positive effects in Acacia-Zizhypus forests of India's Gir sanctuary where livestock (Bubalus bubalis and Bos indicus) and a coexisting native prey (chital deer, Axis axis) are consumed by Asiatic lions (Panthera leo persica). Chital vigilance was higher in areas with low livestock density than in areas with high livestock density. This positive indirect effect occurred because lion predation rates on livestock were twice as great where livestock were abundant than where livestock density was low. Positive indirect interactions mediated by shared predators may be more common than generally thought with rather major consequences for ecological understanding and conservation. We encourage further studies to understand outcomes of indirect interactions on long-term predator-prey dynamics in livestock-dominated protected areas.

An individual's choice of habitat should optimize amongst conflicting demands in a way that maximizes its fitness. Habitat selection by one species will often be influenced by presence and abundance of competitors that interact directly and indirectly with each other (such as through shared predators). The optimal habitat choice will thus depend on competition for resources by other species that can also modify predation risk. It may be possible to disentangle these two effects with careful analysis of density-dependent habitat selection by a focal prey species. We tested this conjecture by calculating habitat isodars (graphs of density assuming ideal habitat selection) of chital deer living in two adjoining dryforest habitats in Gir National Park and Sanctuary, western India. The habitats differed only in presence (Sanctuary) and absence (National Park) of domestic prey (cattle and buffalo). Both species are preyed on by Asiatic lions. The habitat isodar revealed at low densities, that chital live in small groups and prefer habitat co-occupied by livestock that reduce food resources, but also reduce predation risk. At higher densities, chital form larger groups and switch their preference toward risky habitat without livestock. The switch in chital habitat use is consistent with theories predicting that prey species should trade off safety in favor of food as population density increases.

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