Mapping core habitats, landscape permeability, and movement corridors for conservation of desert bighorn sheep in Sonora, México

Mapping core habitats bighorn sheep in Sonora

Abstract

The desert bighorn (Ovis canadensis mexicana) is under Special Protection in México, but populations in Sonora have declined compared to historical levels and are increasingly isolated despite the high economic and ecological value of species.  Consequently, we assessed landscape permeability for desert bighorn in Sonora, using data from 39 GPS/satellite-collared individuals.  We modeled connectivity and least-cost corridors among 95 % aKDE core areas using Circuitscape and Linkage Mapper software from habitat association maps developed using maximum entropy modelling.  We identified a network of 83 potential corridors connecting 43 core areas; corridors ranged from <1 to 165 km in length.  We found two distinct areas in desert bighorn range in Sonora: a southern area characterized by high connectivity with shorter corridors of lesser resistance to movements, and a northern area characterized by much lower connectivity with longer corridors of greater resistance; connectivity between these two areas was limited.  These results illustrate the isolated distribution of many populations of desert bighorn and the limited connectivity between populations in northern and southern Sonora.  Our connectivity maps provide a background for targetting management actions aimed at facilitating the movement and expansion of desert bighorn populations in Sonora.  Consequently, they can guide conservation efforts that identify and promote preservation of key patches or corridors; facilitate habitat restorations within and around corridors; and enhance connectivity and thus viability of populations throughout Sonora.