Range Sizes of the World’s Mammals, Birds, and Amphibians from the Mid-Holocene to the Industrial Period

SIMPLE SUMMARY: The geographic ranges of animal species play an important role for many ecological processes. Changes in climate, as well as human conversion of natural habitats, are two major factors that affect species’ range sizes. While the impact of these two factors in the Industrial era has been thoroughly studied, their pre-Industrial impacts are less well understood further back in time. Here, we combine global reconstructions of land use and climate from 6000 BCE to 1850 CE with data of the geographic distributions and habitat requirements of 16,919 mammal, bird, and amphibian species to estimate how human land use and natural climatic change have altered species’ ranges across past millennia. Our results suggest that pre-Industrial land use had only a small impact, yet one that affected almost all species negatively. Climatic variation evidently led to some range expansions and contractions, but overall had a small impact on the majority of species. In the context of a previous study of range changes in the more recent past, our results demonstrate that current rates of range losses exceed the magnitude of range changes seen over many thousands of years prior to the Industrial period to an alarming extent. ABSTRACT: Anthropogenic land use and climate change in the Industrial age have had substantial impacts on the geographic ranges of the world’s terrestrial animal species. How do these impacts compare against those in the millennia preceding the Industrial era? Here, we combine reconstructions of global climate and land use from 6000 BCE to 1850 CE with empirical data on the spatial distributions and habitat requirements of 16,919 mammal, bird, and amphibian species to estimate changes in their range sizes through time. We find that land use had only a small, yet almost entirely negative impact during most of the study period, whilst natural climatic variability led to some range expansions and contractions; but, overall it had a small impact on the majority of species. Our results provide a baseline for comparison with studies of range changes during the Industrial period, demonstrating that contemporary rates of range loss exceed the magnitude of range changes seen over many thousands of years prior to the Industrial period by an alarming extent.