There has been much criticism of the use of single least cost path approaches for habitat connectivity assessments, yet some other methods such as circuit theory-based analysis are extremely computationally intensive.
As a student in the Master of Environmental Management program at Duke University, Nathan Walker developed methods for multigraph analysis. Multigraphs are made up of multiple low-cost paths, which can differentiate between habitat patches connected through a single narrow corridor, versus patches connected by a wide swath of traversable land.
Our new paper with Dr. Jennifer J. Swenson and Dr. Dean L. Urban, published in the journal Landscape Ecology, evaluates potential movement pathways for the endangered San Martin titi monkey (Plecturocebus oenanthe) by iteratively removing paths and recomputing connectivity metrics. Additionally, a novel innovation for sensitivity analysis was applied; rather than varying costs uniformly across the landscape, we generated landscapes with spatially varying costs to account for uncertainty in land cover mapping based on remote sensing data.
I am proud to see this work published and I hope that these methods will be useful for conservation practitioners. Big congrats to Nathan for his persistence in seeing this through to publication!
Our new paper is out demonstrating the use of multiple low-cost paths for rich and efficient habitat connectivity analysis!