|Humans have modified species distributions in most of the world’s natural ecosystems.
Analyses of species distributions tend to ignore these modifications, potentially masking
the signatures of natural processes on them. We examine the strength of a classic pattern
in ecology—the body mass-latitudinal relationship, aka Bergmann’s rule—for all
mammal species worldwide using both contemporary and estimated natural
distributions. We show that human modifications of mammal species distributions lead
to substantially underestimating the strength of the Bergmann’s rule. We speculate that
other broad-scale ecological patterns might be similarly affected.|