Identification of geophysically diverse locations that may facilitate species’ persistence and adaptation to climate change in the southwestern United States

Context: Conservation of geophysical diversity has been proposed as a strategy for conserving species diversity and facilitating adaptive capacity of species in the face of changing climate. Existing protected areas may not correspond to the most geophysically diverse places because they have typically not been selected on this basis. Objectives: My objectives were to characterize geophysical diversity in the southwestern United States, assess the sensitivity of my results to methodological choices, and assess the degree to which the existing protected areas network in this region captures geophysically diverse places. Methods: I classified the region into geophysically distinct units (land facets) on the basis of topographic and edaphic variables. I calculated land facet diversity on the basis of multiple classification methods, thematic resolutions, and spatial scales (i.e., spatial grain and neighborhood size), assessed the sensitivity of land-facet diversity estimates to these methods, and integrated the results to provide a multi-scaled estimate of geophysical diversity. I used gap analysis to assess the proportion of lands with high land-facet diversity that is protected. Results: Land facet diversity estimates were more sensitive to spatial scale than to methods, but results based on different methods or spatial scales typically were highly correlated. Gaps in the protected areas network include geophysically diverse lands in the Central Basin and Range, Chihuahuan Desert, and Wasatch and Uinta Mountains. Conclusion: The analytical approach and results from this study can provide perspectives and guidance for identifying and prioritizing locations that may facilitate species’ capacity to adapt to climate change.