An Evolutionary Rescue in Polluted Waters
– Andrew Whitehead
The exceptional survivor story of the Gulf killifish was one scientists at the University of California, Davis, Baylor University and their co-authoring colleagues wanted to unveil so they could learn more about what other species may need to adapt to drastically changed environments.
The minnow-like Gulf killifish are an important part of the food web for a number of larger fish species in coastal marsh habitats.
“Most species don’t survive radically altered environments,” said corresponding author Andrew Whitehead, a UC Davis professor of environmental toxicology. “By studying the survivors, we get insight into what it takes to be successful. In the case of the killifish, it came down to huge population sizes and luck.”
They were surprised to find that the adaptive DNA that rescued this Gulf Coast species came from an Atlantic Coast species of killifish, which has also been known to rapidly evolve high levels of pollution resistance. But Atlantic Coast killifish live at least 1,500 miles from their Houston brethren, leaving researchers to think their transport to the Gulf was likely an accident initiated by humans.
“While the vast majority of research on invasive species rightly focuses on the environmental damage they can cause, this research shows that under rare circumstances they can also contribute valuable genetic variation to a closely related native species, thus acting as a mechanism of evolutionary rescue,” said co-corresponding author Cole Matson, an associate professor at Baylor University.
“The adaptation of these killifish is a cautionary tale,” Whitehead said. “It tells us what we need to do better for the vast majority of species that don’t have access to the kind of genetic resources killifish have. If we care about preserving biodiversity, we can’t expect evolution to be the solution. We need to reduce how much and how quickly we’re changing the environment so that species can keep up.”
“We are challenging animals by rapidly transforming their surroundings into extreme environments,” said first author Elias Oziolor, who was a postdoctoral fellow in Whitehead’s lab. “However, some, like the Gulf killifish, have been fortunate to find creative and novel ways to persist. My hope is that our work can motivate efforts in conserving our environment by better understanding and mitigating human impacts on populations.”
Additional coauthoring institutions include the University of Connecticut and Indiana University.
The work was supported by funding from a C. Gus Glasscock Endowed Research Fellowship, Baylor University, the Exxon-Valdez Oil Spill Trustees Council, National Science Foundation, National Institutes of Environmental Health Sciences and Indiana University.