AN EVALUATION OF THE PRESERVATION POTENTIAL OF TERRESTRIAL GEOGRAPHIC RANGE SIZE, A SIMULATIONS-BASED APPROACH

The geographic range is a fundamental property of species, and range size is a central criterion used by the IUCN for assessing extinction risk. Increasingly, paleontologists are examining the relationships between geographic ranges and extinction over past biotic crises, both as a means of studying the long-term drivers of extant macroecological and macroevolutionary patterns, and (potentially) to help predict which species may be most at-risk in a putative and ongoing ‘6^th mass extinction’ event. However, there remain outstanding questions surrounding to what extent we can accurately reconstruct geographic range sizes in the fossil record. Simulations-based frameworks allow for the exploration of the nuances of range size preservation. Previous studies indicate that the rank order of geographic range sizes can be preserved with surprisingly high fidelity, however, these studies did not account for the varying taphonomic potentials among species. Moreover, the extent to which reconstructed ranges are consistently truncated among species, biomes, and with a spatially-variable fossil record – something that might allow us to reconstruct absolute range size – remains to be investigated. Here, we present early results stemming from a suite of experiments quantifying the preservation potential of geographic range size among North American terrestrial mammals. These experiments use the ranges of 371 extant species, and reconstruct geographic ranges (measured as convex hulls, latitudinal range, and maximum great circle distance between occurrences) after iteratively simulating fossil localities and applying a stepped series of taphonomic filters. These preliminary results reinforce previous findings that the rank order of geographic range sizes has high preservation potential, but also identify consistent patterns in range truncation. Indicating that paleorange reconstruction may help us identify and protect the most vulnerable species of terrestrial mammals in the face of ongoing global change.