Examining local and regional ecological connectivity throughout North America

Context Conservation scientists recommend maintaining and restoring ecological connectivity to sustain biodiversity in the face of land-use and climate change. Alternative connectivity assessments conducted at multiple spatial scales are needed to understand consequences of varying assumptions and for use in multi-scale conservation planning. Objectives We compared mapped output from different model scenarios conducted to identify areas important for ecological connectivity across North America. We asked how areas important for connectivity vary with spatial scale and assumptions regarding the way in which human modification affects landscape resistance. Methods We conducted a factorial experiment using omnidirectional connectivity analyses across North America where we crossed "treatments" represented by four moving window sizes and three resistance surfaces. The three resistance surfaces represent a gradient in species' sensitivity to human modification. Results Maps of connectivity importance varied among scenarios. The effects of moving window size were more conspicuous than effects of different resistance surfaces. Outputs from small moving windows revealed mottled patterns of connectivity importance, while outputs from larger moving windows revealed broad swaths of connectivity importance across mountainous and boreal areas of North America. Patterns of connectivity importance tended to be more channelized from resistance surfaces produced to represent more human-sensitive species and more diffuse from resistance surfaces produced to represent more human-tolerant species. Conclusions Our scenarios and output represent alternative hypotheses and predictions about how multiple species may move in response to varying degrees of human modification. Our output can be compared to species-specific models to investigate which of our scenarios best matches observed movements of organisms. Our output can also be used as coarse-filter and multi-scale connectivity assessments for conservation plans. Notably, our outputs highlight the importance of small and isolated fragments of relatively natural land while simultaneously identifying broad regions important for maintaining connectivity across natural areas of North America.