Road-crossings, vegetative cover, land use and poisons interact to influence corridor effectiveness

Abstract

Landscape connectivity is essential to conserving resilient wildlife populations in the Anthropocene. Maintaining connectivity requires preserving or restoring patches of habitat, accounting for the behavioral factors that determine movement between patches and mitigating threats. We measured natural and anthropogenic features that influence movement and mortality for bobcats (Lynx rufus) in a system threatened with complete isolation by urbanization. Our overarching objective was to inform local land acquisition and restoration to maintain two last-chance wildlife corridors. We collected five-minute movement data from 36 bobcats in central California to assess features of road-crossing hotspots and model habitat selection, including functional responses to housing densities and vegetation. We collected opportunistic mortalities and assessed rat poison exposure to evaluate edge effects as acute threats. Bobcats strongly selected for natural vegetation, evident at the level of a single tree or shrub. Individuals selected low-density housing (<5 houses/ha) yet avoided high-density housing development and monoculture agriculture. Narrow (<25 m wide) riparian strips were critical to connectivity. Bobcats successfully crossed the busiest highway in the landscape but frequently died when crossing a less-trafficked road with a high median barrier. Vehicles and disease were dominant sources of mortality, while 94% of bobcats were exposed to rat poisons despite California's 2014 regulations implemented to reduced wildlife exposure. Maintaining landscape connectivity requires conserving key habitats, mitigating the effects of infrastructure, and sustaining populations of highly mobile, healthy individuals. Our findings have driven conservation action through land acquisition. We demonstrate how robust, rapid data collection can facilitate real-world conservation outcomes.