| Intensifying human development requires landscape-level planning to restore connectivity to fragmented and ecologically isolated habitats. The rapidly growing field of conservation planning has produced a variety of approaches to modeling habitat connectivity. The objective of this research is to inform the choice and use of appropriate software packages for connectivity conservation planning. I focused on comparing two prevalent approacheds, 1) least cost path, patch-patch modeling using CorridorDesigner software and 2) electrical circuit-theory based approaches for patch-patch and "all points" connectivity using Circuitscape software. Additionally, I compared two dominant connectivity modeling approaches: 1) the focal species approach and 2) a generalized resistance approach using a "naturalness" dataset. When using the same input layers and varying only the software, I found considerable differences in spatial characteristics of outputs, between least cost path (LCP) and circuit theory (CT) approaches including 1) greater specificity of LCP corridors, and 2) spatial disjuncts between LCP corridors and CT areas of high current flow. Mean resistance values for Circuitscape outputs were different than means for CorridorDesigner, suggesting Circuitscape's different algorithm producesdifferent corridors than CorridorDesigner. As the underlying assumptions of LCP and CT differ, it is not surprising that their outputs would as well, even when using the same input variables. However, conservation planning practitioners need to be aware of these modeling assumptions prior to implementing corridors. The increased specificity of LCP corridors produced by CorridorDesigner and the intuitively accessible LCP concept suggests ease of application but perhaps the risk of bias due to overspecificity. Alternatively, while circuit theory is intuitively apealing because it is a more wholistic lansdscape-level-analysis, and has useful, spatially-explicit "pinch points", it may produce output that is too vague for local-land use planners. Conservation planning webinars and other trainings will help land use planners understand the differences among connectivity modeling assumptions, data structures, and outputs. |
