Long-term conservation effects of protected areas in stochastic population dynamics

Abstract

Terrestrial and marine protected areas have been essential tools to mitigate anthropogenic impacts and promote population persistence and resource sustainability. Adequately implemented protected areas promote a long-term conservation benefit. Stochasticity affects its long-term performance, and necessary to understand the general influence. Here, we investigate a long-term conservation benefit via stochastic models that encompass demographic or environmental stochasticity. We quantify a long-term conservation benefit by the coefficient of variation (CV) of population size in protected areas, where a low CV indicates high robustness against stochasticity. We demonstrate that adequately implemented protected areas promote a long-term conservation benefit under stochasticity and decrease otherwise. However, demographic and environmental stochasticity induce rather different consequences, although the former is suppressed with the population size. Multiple parameters in our framework determine the quality of protected areas, and systematic investigations for various scenarios facilitate an effective management decision.