Utilizing a top predator to prioritize site protection for biodiversity conservation.

Ongoing global change makes it ever more urgent to find creative solutions for biodiversity preservation, but prioritizing sites for protection can be challenging. One shortcut lies in mapping the habitat requirements of well-established biodiversity indicators, such as top predators, to identify high-biodiversity sites. Here, we planned site protection for biodiversity conservation by developing a multi-scale species distribution model (SDM) for the raptorial Northern Goshawk (Accipiter gentilis; goshawk) breeding in an extensive megacity region of Japan. Specifically, we: (1) examined the determinants of top predator occurrence and thus of high-biodiversity value in this megacity setting, (2) identified the biodiversity hotspots, (3) validated whether they actually held higher biodiversity through an independent dataset, and (4) evaluated their current protection by environmental laws. The SDM revealed that goshawks preferred secluded sites far from roads, with abundant forest within a 100 m radius and extensive forest ecotones suitable for hunting within a 900 m radius. This multi-scale landscape configuration was independently confirmed to hold higher biodiversity, yet covered only 3.2% of the study area, with only 44.0% of these sites legally protected. Thus, a rapid biodiversity assessment mediated by a top predator quickly highlighted: (1) the poor development of biodiversity-friendly urban planning in this megacity complex, an aspect overlooked for decades of rapid urban sprawl, and (2) the extreme urgency of extending legal protection to the sites missed by the current protected area network. Exigent biodiversity indicators, such as top predators, could be employed in the early or late stages of anthropogenic impacts in order to proactively incorporate biodiversity protection into planning or flag key biodiversity relics. Our results confirm and validate the applied reliability of top predatory species as biodiversity conservation tools.