Greater Sage-grouse Linkage Zones in the SageCon study area, southeastern and central Oregon

This dataset is a component of habitat connectivity analyses for Greater Sage-grouse (GSG) in southeastern and central Oregon conducted in 2014 in accord with the Sage Grouse Conservation Partnership (SageCon) by The Nature Conservancy in Oregon (TNC) – see Jones (2015). The dataset consists of ‘linkage zones’, broad belts of land with relatively greater habitat continuity. Delineated by the spatial extent of normalized least-cost corridors, or NLCCs, linkage zones define the extent within which both pinch-points and barriers are identified.

The surface was produced using the open source Circuitscape program (McRae and Shah 2009)as called from the Pinchpoint Mapper tool in the Linkage Mapper toolbox (McRae and Kavanagh 2011). Circuitscape uses circuit theory – a branch of graph theory with a lexicon and algorithms specific to analysis of electrical circuit topologies –to model habitat connectivity across landscape mosaics. With the study landscape represented as a conductive surface, metrics including ‘effective resistance’, current flow, and voltage can be calculated to represent ecological processes such as individual species movement or gene flow across a metapopulation. In kind with graph theory more broadly, the circuit theoretic framework supports concurrent analysis of not only multiple but all possible species movement routes across a landscape (McRae and Shah 2009).

For each linkage in this study, current was applied between the associated pair of lek kernels. The current was run over squared resistance values to increase contrast in the resistance raster, and flow for each linkage zone was limited to areas below the same CWD distance threshold (10 cw-km) used to map the NLCCs.