Global correlates of range contractions and expansions in terrestrial mammals

Michela Pacifici,James E M Watson,Andrea Cristiano,Jonathan R Rhodes,John C Z Woinarski,Carlo Rondinini,Andrew A Burbidge,Moreno Di Marco

doi:10.1038/s41467-020-16684-w

Abstract

Understanding changes in species distributions is essential to disentangle the mechanisms that drive their responses to anthropogenic habitat modification. Here we analyse the past (1970s) and current (2017) distribution of 204 species of terrestrial non-volant mammals to identify drivers of recent contraction and expansion in their range. We find 106 species lost part of their past range, and 40 of them declined by >50%. The key correlates of this contraction are large body mass, increase in air temperature, loss of natural land, and high human population density. At the same time, 44 species have some expansion in their range, which correlates with small body size, generalist diet, and high reproductive rates. Our findings clearly show that human activity and life history interact to influence range changes in mammals. While the former plays a major role in determining contraction in species’ distribution, the latter is important for both contraction and expansion.

Highlights

Understanding changes in species distributions is essential to disentangle the mechanisms that drive their responses to anthropogenic habitat modification
Anthropogenic and life-history factors have significantly influenced the distribution of mammals in the recent past
We found that while both range contractions and expansions have occurred, the number of mammal species that underwent an overall decrease in range size since the 1970s was twice the number of species that underwent an overall increase

Summary

Introduction

Understanding changes in species distributions is essential to disentangle the mechanisms that drive their responses to anthropogenic habitat modification. Our findings clearly show that human activity and life history interact to influence range changes in mammals. While the former plays a major role in determining contraction in species’ distribution, the latter is important for both contraction and expansion. Declines in this period have been documented for ungulates and carnivores, where for every species that improved its Red List status, eight have deteriorated[7] These trends likely started before the beginning of the third industrial revolution, in combination with shifting cultural values that led to the overexploitation of natural resources and an increase in land pollution[8]. Several studies on different taxonomic groups have attempted to identify the relative importance of life-history traits in determining range size and change[17,18]

Methods

Results

Conclusion