2.7 Quantifying connectivity properties
We identified the least-cost paths using Linkage Mapper v. 2.0.0. (McRae and Kavanagh, 2011 ), a GIS toolbox developed for connectivity analysis based on cost-weighted distance surface. We used the core area (protected area) polygons and resistance raster to perform cost-weighted distance calculations from each protected area. As each cost-weighted distance surface is created, Linkage Pathways also extracts minimum cost-weighted distances between source and target core area pairs. Once the linkage zones have been mapped using Linkage Mapper, the Centrality tools from the Linkage Mapper toolbox were used to calculate current flow centrality across the networks. Current flow centrality is a measure of how important a link or core area is for keeping the overall network connected.
To identify the barrier areas and priority areas of connectivity restoration,we used the Barrier Mapper tool from Linkage Mapper. Barrier Mapper detects important barriers that affect the quality and/or location of the corridors using a circular search window. Results give expected reduction in least-cost distance per unit distance restored assuming pixels in the window are changed to a resistance of 1.0. Greater reductions in cost-weighted distance (i.e. increase in connectivity) indicate areas of greater restoration potential (McRae, 2012 ). We applied a single moving window radius (110 km) to search. This range accounts for the maximum dispersal capacity of North China leopard. For each pixel we calculated the sum of connectivity improvement scores taken across all core area pairs, highlighting areas that impede movement between multiple pairs of conservancies.