Guanaco predation by pumas and its relationship to Patagonian food webs

Abstract

Interactions involving ungulates their predators are widely thought to shape ecological patterns and processes. Guanacos (Lama guanicoe) and pumas (Puma concolor) have coexisted in South America for at least one million years. Within Patagonian arid-land ecosystems guanaco predation by pumas can account for high levels of mortality, but the potential for this interaction to affect other trophic levels remains unknown. Here, we review and synthetize data on guanaco-puma interactions, as well as other key aspects of guanaco ecology. We frame this information within food web theory to evaluate whether guanaco predation by pumas could directly and indirectly influence vegetation, scavengers, and nutrient dynamics. We then outline a proposed test of our hypotheses about the influence of the guanaco-puma interaction on communities and ecosystems. Conducting the test would shed light on a barely known interaction and inform current attempts for sustainable utilization of guanacos. Ultimately, critical ecological mechanisms, such as predator-prey interactions involving large mammalian predators and their ungulate prey, will be conserved only if these mechanisms are explicitly recognized and understood.