A NOVEL STATISTICAL METHOD TO DETECT BIOTIC AND ABIOTIC DRIVERS OF GEOGRAPHIC RANGE EVOLUTION WITH PALEONTOLOGICAL DATA

Global biodiversity through time is governed by the interplay between speciation and extinction. Regional biodiversity dynamics are additionally shaped by dispersal, expanding the range of taxa and range contraction via local extinction. New methods using paleontological data have greatly improved our knowledge on how speciation and extinction dynamics are driven by biotic factors (e.g., diversity-dependent speciation) and abiotic indicators (e.g., effects of environmental change on extinction). In contrast, biological questions about the drivers of geographical range evolution remain largely unexplored due to the lack of statistical methods that link dispersal and extinction with biotic and abiotic covariates. Here we present a new set of dispersal-extinction-sampling (DES) models, which estimates dispersal and extinction rates from the present and past biogeographical distribution of taxa while accounting for the incompleteness of the fossil record via sampling rates. The new framework includes (a) the incorporation of heterogeneity in fossil sampling across taxa, which significantly improves the accuracy in estimating the remaining model parameters, (b) the implementation of models specifically designed to test the effect of biotic and abiotic factors on dispersal and local extinction rates, and (c) a fast maximum likelihood search algorithm for efficient model testing. We benchmark the DES models by simulating different scenarios of biotic/abiotic-dependent range evolution to assess the accuracy of the estimated parameters and the statistical power to identify the correct models. Finally, we test our framework on a dataset of North American and Eurasian mammalian carnivores to assess whether sea‑level changes over the last 40 million years fostered intercontinental dispersal via increased connectivity and competitive effects of incumbent and immigrant species on local extinctions.