Comparison of six methods for stabilizing metapopulation dynamics and for their robustness against census noise

Natural populations often encounter heightened risks of extinction due to mismatches between their inherent traits and the ecological contexts they inhabit. These risks amplify with the ongoing degradation of wild habitats and climatic shifts. Recognizing that not all populations can prevent extinction independently, several methods have been theoretically proposed to protect vulnerable populations using external interventions. Yet, these methods are under-explored in spatially structured populations, or metapopulations, and remain untested in the presence of potential census inaccuracies. In this study, we assessed six population stability methods, previously validated in isolated populations, comparing their efficacy in metapopulations, using comprehensive biologically realistic simulations. We employed a recognized composite index to compare the performance of the population stability methods based on their stability outcomes and associated implementation costs. Our evaluations encompassed a range of ecological conditions, factoring in population growth rate, capacity, and migration patterns, inclusive of both symmetric and asymmetric migration. Without external interventions, we observed unique dynamics across these conditions, each with differing extinction susceptibilities. Remarkably, to decrease extinction probabilities to a specified threshold, the Adaptive Limiter Control method was consistently superior irrespective of the original dynamics. Conversely, for curbing population size fluctuations, the Lower Limiter Control emerged as the most potent, trailed closely by the Adaptive Limiter Control and Both Limiter Control methods. Importantly, these method rankings remained consistent even amidst varying census uncertainties. Our results offer a foundation for developing policies and conservation strategies with specific actionable recommendations, particularly in the management of natural populations facing extinction risks.