Connectivity analysis of mountain sheep habitats (Ovis vignei arkal) to locate a highway corridor in Golestan National Pak using an integrated approach of Circuit and Graph theories

Roads and highways, as one of the biggest threats to wildlife survival, severely affect the ecological connectivity status of the landscape leading to the fragmentation of existing habitats. This research examines the effect of the Tehran-Mashhad bypass road through the Golestan National Park on the movement of Ovis vignei arkal to identify the best point for locating a connectivity corridor. In this study, multiple scales and theories have been selected to analyze species connectivity. The circuit theory was used for the landscape scale by modeling the bottleneck index, and graph theory was used for the patch scale by calculating the betweenness centrality index (BC). The optimal place for locating the corridor was identified by overlaying the range of the bottleneck index and the shortest path to the patch with the highest BC value. By integrating the circuit and graph theories, the results demonstrated the higher movement patterns in the region's west side due to the higher habitat suitability. Installing a corridor in this spot will be increased the species' movement, maintain its population, prevent species isolation, and consequently improve the state of the downstream habitats.