Ensemble modeling to identify high conservation value areas for endemic and elusive large-sized mammals of the Philippines

Abstract

Bubalus mindorensis (tamaraw) and Sus oliveri (Mindoro warty pig) are emblematic of Mindoro Island as a faunal biodiversity hotspot in the Philippines. However, these endemic, red-listed mammals are of socioecological concern due to pressures within their contracting home ranges. Conservation efforts are logistically hindered by their elusive yet aggressive behavior and coexistence with indigenous tribes. This study aims to identify high conservation value areas (HCVAs), sites where both species are highly suitable. Ensemble species distribution modeling (SDM) based on nine algorithms was performed. For each species, three ensemble SDMs were calibrated following three proposed approaches in decreasing hyperparameter-based model complexity: standard, tuned, and limited. Across ensemble SDMs, complexity and True Skill Statistics (TSS)-based accuracy are positively associated. Still, the limited ensemble SDM of tamaraw (TSS = 0.740) and Mindoro warty pig (TSS = 0.855) retain good discriminatory performance. These coincidingly predict that known occurrence sites are areas of high suitability, which are spatially fragmented into four patches across the Mindoro Mountain Range: Mt. Calavite Wildlife Sanctuary, Upper Amnay Watershed, Aruyan-Malati, and Mts. Iglit-Baco National Park. In total, these prospective HCVAs cover 405.17 km2 (3.83%) of Mindoro Island, which represent areas of priority for the ongoing Mindoro Island Biodiversity (BD) Corridor Project. This study substantiates the need for strategic management of these HCVAs. Despite overarching study-specific limitations and uncertainties, this study advocates the informed use of ensemble SDMs for reserve selection, conservation planning, and wildlife-related policymaking in Mindoro Island.