Ecological drivers of guanaco recruitment: variable carrying capacity and density dependence

摘要: Ungulates living in predator-free reserves offer the opportunity to study influence of food limitation on population dynamics without potentially confounding effects top-down regulation or livestock competition. We assessed relative forage availability and density guanaco recruitment two eastern Patagonia, with contrasting scenarios density. also explored contribution observed growth using a deterministic linear model test assumption that studied populations were closed units. The densities increased twice as fast our theoretical populations, indicating marked immigration has taken place during recovery phase experienced by both thus we rejected closed-population assumption. Regarding factors driving variation recruitment, low- medium-density setting, found positive relationship between surrogates annual primary production, whereas no dependence was detected. In contrast, high-density scenario, production showed effects, per capita above food-limitation threshold. Our results support idea environmental carrying capacity fluctuates response climatic variation, these fluctuations have relevant consequences for herbivore dynamics, such amplifying drier years. conclude including coupling variability resources is crucial ungulate dynamics; overlook temporal changes may even mask well other important processes.