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Dryad

Landscape layer for resistance

Data files

Dec 16, 2021 version files 8.37 KB

Abstract

This is raster file (base_cats_new3.asc) that was used to generate the environmental resistance surface with the ResistanceGA R package (Peterman, 2018) to evaluate models of environmental resistance to between-population movement of saltwater crocodiles Crocodylus porosus in the Northern Territory of Australia, represented by individual pairwise genetic distances among individuals. ResistanceGA models pairwise genetic distances in response to pairwise ‘ecological distances’ using linear mixed effects models with a maximum-likelihood population effects (MLPE) random effects structure (Clarke, Rothery, & Raybould, 2002), represented by individual ID in our models. We used Smouse and Peakall (1999) pairwise genetic distance as the response variable for this purpose.We estimated resistance surfaces that optimised random-walk commute distances (Etten, 2018) among the locations of sampled individuals as an explanatory variable in models of pairwise genetic distances among individuals. We ran a single surface optimisation in ResistanceGA (Peterman, 2018) to generate resistance values for the six environmental cover categories and stopped each model after 25 consecutive generations of no improvement in log-likelihood.