Global topographic uplift has elevated speciation in mammals and birds over the last 3 million years

Geology and climate affect speciation. A combination of path analysis applied to palaeo-reconstructions of mammals and birds with analysis of palaeoclimatic data shows that uplift over the last 3 million years explains more spatial variation in speciation than the direct effects of palaeoclimate change or present-day elevation and temperature. Topographic change shapes the evolution of biodiversity by influencing both habitat connectivity and habitat diversity as well as abiotic factors like climate. However, its role in creating global biodiversity gradients remains poorly characterized because geology, climate and evolutionary data have rarely been integrated across concordant timescales. Here we show that topographic uplift over the last 3 million years explains more spatial variation in the speciation of all mammals and birds than do the direct effects of palaeoclimate change and both present-day elevation and present-day temperature. By contrast, the effects of topographic changes are much smaller than those of present-day temperatures in eroded areas. Together, our results stress that historical geological processes rather than traditionally studied macroecological gradients may ultimately generate much of the world's biodiversity. More broadly, as the Earth's surface continues to rise and fall, topography will remain an important driver of evolutionary change and novelty.

Automated summary

Research has shown that uplift over the last 3 million years has a significant impact on the speciation of all mammals and birds, with topographic changes playing a larger role than direct effects of paleoclimate change and present-day elevation and temperature. Historical geological processes may ultimately generate much of the world's biodiversity, highlighting the importance of topography as a driver of evolutionary change and novelty on Earth's surface.