Energetics-based connectivity mapping reveals new conservation opportunities for the endangered tiger in Nepal

Abstract

Enhancing habitat connectivity is a key strategy for conserving endangered species in anthropogenic landscapes. However, connectivity planning often overlooks the crucial energetic costs to animals of traversing complex terrains. We applied a novel approach for estimating energy costs of movement for tigers – a globally endangered species. We used those estimates to calculate landscape connectivity for these animals across the extreme altitudinal gradient of Nepal, where recent sightings of tigers at higher elevations (~3200 m) suggest an upward range expansion from the tiger-rich lowlands. To evaluate our estimates, we simulated tiger routes to higher-elevation locations and compared modeled energy costs of those ascents to those derived from a previous model calibrated with data from GPS-collared tigers in Russia. In areas below 3200 m, we found about 7.5 times greater land areas with high connectivity outside protected areas (~51 000 km²) than inside (~6800 km²). However, most of the highly connected areas below 3200 m consist of croplands (56%). Importantly, community-managed forests, which spanned the altitudinal gradient, tended to include areas with moderate levels of connectivity. Our estimates of energy costs and those from Russia showed a strong consensus (ρ = 0.70, P < 0.05), with ours better capturing the higher energy costs of traversing mountains and of very large total ascents. Our results show that while barriers to tiger movement across Nepal are ubiquitous, other effective area-based conservation measures (OECMs), like community-managed forests, can play prominent roles in promoting tiger habitat connectivity while minimizing human–tiger conflict across anthropogenic landscapes. Our results also underscore the utility of integrating first principles of energy efficiency into connectivity analyses and planning.