Â鶹ÒùÔº

Mountains as biodiversity engines: How uplift may shape species evolution

A new study co-authored by researchers at Indiana University sheds light on how the forces that shape mountain ranges also influence the evolution of species. In the study, "Direct effects of mountain uplift and topography on biodiversity," in Science, researchers found that biodiversity increases as mountains rise, suggesting that geological processes play a direct role in the shaping of life on Earth.

In their study, the authors utilized advanced computer models to explore how species evolve in response to shifting landscapes, and their findings reveal a strong link between the rate and magnitude of tectonic uplift and the creation of new species, particularly among small mammals like rodents.

These findings have major implications for evolutionary biology, paleontology, and conservation. By establishing a direct link between geological activity and biodiversity, the research provides a framework for understanding how past climate and tectonic changes shaped ecosystems over millions of years.

The study was co-authored by Eyal Marder, a postdoctoral researcher at the University of Massachusetts Amherst and a former postdoctoral fellow at IU, Brian Yanites, Associate Professor of Earth and Atmospheric Sciences and others.

Mountains as biodiversity hotspots

For decades, scientists have observed that mountain regions host an incredible diversity of life. However, it has remained unclear whether high biodiversity results from evolutionary processes responding to landscape changes, or if other factors were at play.

This new research provides evidence that the rise of mountains directly contributes to species diversity by creating new habitats and isolating populations, leading to the formation of new species.

The team built upon "Adascape," a specialized computer model that simulates how species evolve in response to shifting landscapes, and developed new special computer programs to create a virtual world where they could watch how different species change and grow as mountains slowly form over millions of years.

The computer models helped the scientists see how new species appear and how animals move around in response to the rising mountains.

"The simulations revealed that as mountains rise, species adapt to new elevations and become geographically isolated, spurring the emergence of new species through a process known as allopatric speciation," notes Professor Yanites.

Revealing the connections

To understand the connection between mountain-building and biodiversity, the researchers ran simulations over a 20-million-year timescale. They began with a flat landscape populated by a single species of rodent-like mammals. As virtual mountains formed, these animals dispersed and adapted to their surroundings, eventually evolving into multiple distinct species.

One key aspect of the study was examining how biodiversity patterns in the mountains compared to those in adjacent lowlands, where fossil records are more commonly preserved.

The researchers found that while species originated in the mountains, many eventually spread to lower elevations, helping to explain patterns seen in ancient fossil records. For example, a spike in fossil biodiversity approximately 15 million years ago in the western U.S. could be associated with the growth of local mountains and sediment sinks in the geographic region known as the Basin and Range Province.

"This study gives us new insights into how Earth's physical processes influence the diversity of life," said Dr. Marder. "It also highlights how ongoing geological changes could continue to impact biodiversity in the future."

Professor Yanites emphasized the importance of integrating geology and biology in understanding evolution. "We often think of landscapes as passive backdrops for evolution, but this study shows that they are active participants in shaping biodiversity," he said.

In addition, the study may help guide conservation efforts; as climate change and human activity alter mountain ecosystems, understanding how species respond to environmental shifts can inform strategies to protect biodiversity in these regions.

Conservationists may be able to use these findings to predict which species are most at risk from environmental changes, and develop targeted strategies to preserve mountain biodiversity.

A new way to study life's evolution

The researchers believe their modeling approach could be applied to other types of landscapes and species groups, offering a new way to study the long-term effects of environmental change. Future work may integrate fossil evidence and genetic data to further validate these models and refine predictions about how species evolve in response to shifting landscapes.

Importantly, the research underscores the deep connections between Earth's geological and biological history, revealing that the same forces that build mountains also shape the diversity of life around them.