In a new study published in Ecology Letters, scientists show that genetic diversity plays a significant role in determining whether species can shift their ranges as temperatures warm.  

The study, co-authored by National CASC scientists, integrated the largest global databases of species range shifts and genetic diversity, analyzing more than 4,600 range shift estimates for nearly 1,900 species, including insects, arachnids, birds, fish, and plants. They found that the speed and direction of range shifts depended on interactions between genetic diversity, where populations are located within the species’ range, and the rate at which conditions are changing, known as climate velocity.  

As change accelerates, species generally have two options: ‘persist in place’ by adjusting to new conditions, or ‘move in space’ to follow suitable conditions. This study demonstrates that genetic diversity affects both options, depending on where a population occurs within the species’ geographic range.  

At the trailing edge (the part of a species’ range that is becoming less hospitable), species with higher genetic diversity experienced less range contraction under rapid warming. In other words, they were able to persist in places that were changing fast. Higher genetic diversity in these areas likely provides populations a higher capacity to tolerate and adapt to changing conditions.  

At the leading edge (the expanding boundary of a species’ range where newly suitable habitat is emerging, such as cooler poleward regions), species with higher genetic diversity expanded more quickly under more moderate change. Higher genetic diversity in these areas may provide populations a greater chance at successfully dispersing and settling in new locations. Conversely, species with low genetic diversity were more vulnerable at the trailing edge and slower to advance at the leading edge. However, under rapid climate change, less genetically diverse species shifted faster at the leading edge, suggesting that the role of genetic diversity also depends on the level of climate change exposure. 

The findings clarify how genetic diversity influences climate-driven range dynamics, either by buffering species against range contractions or enabling range expansions. For conservation managers, these results can help predict species vulnerability to climate change and guide decisions, such as preserving landscape connectivity and genetic diversity to facilitate adaptation and movement. 

The study, Genetic Diversity Impacts Climate-Induced Species Range Shifts, was published in Ecology Letters.