PaNP is a Key Biodiversity Area and an Important Bird Area. Its contiguous block of old and secondary growth dipterocarp forest covers almost 90% of its area. In addition, Birdlife International (2018) reports that: “Many of the threatened and restricted-range species of the Mindanao and Eastern Visayas Endemic Bird Area have been recorded in or near to Pasonanca Watershed, including recent records of the threatened Mindanao Bleeding-heart, Silvery Kingfisher, Philippine Leafbird and Little Slaty Flycatcher, and Zamboanga Bulbul, which is confined to the protected area and a subspecies from Western Mindanao and Basilan”. PaNP encompasses four watersheds, each with separate water catchment areas and river systems: Pasonanca Watershed, Ayala Watershed, Manicahan watershed, Culianan and Bolong Watershed.