Moving through the matrix: Promoting permeability for large carnivores in a human-dominated landscape

Abstract

Landscape connectivity for wildlife populations is declining globally due to increasing development and habitat fragmentation. However, outside of full protection of undeveloped wildlife corridors, conservation planners have limited tools to identify the appropriate level of densification such that landscape permeability for wildlife is maintained. Here we sought to determine the development characteristics that contribute to movement potential in an exurban landscape for a large carnivore, the puma. We first fit a piecewise step-selection function from movement paths from 28 male pumas to identify threshold levels of development that produce barriers to movement. We then applied this threshold to projected housing densities of existing parcels under a full General Plan buildout scenario in Santa Cruz County to illustrate how parcels at risk of increasing above the puma movement threshold can be identified. Finally, we tested the relative importance of characteristics associated with parcels and the surrounding area on relative puma movement. We found that pumas exhibit avoidance of housing density that saturates at a threshold, and that puma utilization of parcels at risk of densification above this threshold is predicted by parcel area and the housing density and area of surrounding parcels. Our work suggests that maintaining permeability in developing landscapes is likely contingent on preventing densification and parcel subdivision in exurban areas. We discuss how our findings and approach can be used by conservation planners to promote landscape permeability in already partially developed landscapes.