Mountain Uplift, Topography Shape Deep Time Biodiversity

Rising mountains do more than reshape the landscape – they also drive evolutionary change, according to a new study. By simulating millions of years of tectonic uplift, researchers have uncovered a link between mountain building and biodiversity, shedding light on how Earth's dynamic topography shapes biodiversity over deep time. Mountain ranges are widely recognized as global hotspots of terrestrial biodiversity yet only cover a relatively small proportion of the Earth's surface, suggesting a strong connection between topographic evolution and species diversity. Mountainous terrain can promote speciation by isolating populations, fostering genetic divergence, and enabling adaptive radiations across diverse ecological niches. Additionally, landscape changes driven by tectonics, climate, and river dynamics influence species distributions over time. However, the evolutionary mechanisms that drive the link between mountain uplift and topography on biodiversity are poorly understood. Using coupled landscape and biological models and a novel biologically simplified speciation algorithm, Eyal Marder and colleagues investigated how mountain-building processes alone shape biodiversity over geological timescales. Using the model, Marder et al. simulated various mountain-building scenarios over 20 million years to examine how species richness patterns responded to realistic tectonic uplift rates. They found that tectonic and geomorphological activity not only shapes species richness in high-elevation mountain regions but also leaves detectable imprints in adjacent lowland basins. According to the model's findings, species richness increases in direct proportion to the magnitude and pace of mountain building, as well as the pace of topographic development, which are all influenced by tectonic rock uplift rates. Moreover, Marder et al. show that speciation lags the onset of mountain building, with species richness reaching equilibrium once topographic relief stabilizes. While erosional highlands foster higher species richness likely due to population isolation, species richness remains strongly correlated between highlands and lowlands, suggesting that lowland biodiversity dynamics mirror those in adjacent mountain ranges. According to the authors, the alignment between the model's results and real-world biodiversity patterns highlights the significant role of topography and tectonics in shaping biodiversity.