Science Source

Gerardo Ceballos, Paul R. Ehrlich, Rodolfo Dirzo

Proceedings of the National Academy of Sciences

Published date July 10, 2017

Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines

Analyzes the numbers and degrees of range contraction using a sample of 27,600 vertebrate species, and on a more detailed analysis documenting the population extinctions between 1900 and 2015 in 177 mammal species
Finds that the rate of population loss in terrestrial vertebrates is extremely high—even in “species of low concern"
Finds that 32% of species sampled have decreased in population size and range
Results show that all 177 mammals for which the authors have detailed data have lost 30% or more of their geographic ranges
Data indicate that beyond global species extinctions Earth is experiencing a huge episode of population declines and extirpations, which will have negative cascading consequences on ecosystem functioning and services vital to sustaining civilization
Describes this as a “biological annihilation” to highlight the current magnitude of Earth’s ongoing sixth major extinction event