SBEARS—a site-based method to estimate ancestral ranges of species

Assessing the geographic dimension of diversification is paramount to integrate macroecology and macroevolution. Estimating ancestral ranges of species from phylogenies and spatial distribution of extant species has been fundamental for historical biogeography and can help in this endeavor. Yet, improvements in the available tools to estimate ancestral ranges are still necessary to produce fine-grained spatial reconstructions. We introduce a method called SBEARS (Site-Based Estimation of Ancestral Range of Species) to reconstruct ancestral ranges at finer grain resolutions, which does not require a priori definition of biogeographic regions and provides information about the spatial distribution of ancestral nodes in a user-friendly format. We test the robustness of SBEARS using simulated datasets and thereby demonstrate that the method reliably reconstructs ancestral ranges at rates higher than other methods implemented in the R packages BioGeoBEARS and rase. Further, we employ SBEARS to reconstruct ancestral ranges of Sigmodontinae rodents and compare them to those generated by BioGeoBEARS and rase. SBEARS builds upon other available methods as a reliable alternative for ancestral range reconstruction where a fine-grain geographic resolution is required.