UW Professor Examines How Pollutants Impact Invasive Animal Species

Wildlife species throughout the world are contending with both chemical pollutants and invasive species. In a newly published review, a University of Wyoming researcher examined how chemical pollution might change the invasion process and identified gaps in current knowledge about the interactions of pollution and invasive species.

Isaac Ligocki, an assistant professor in the UW Department of Zoology and Physiology, is the lead author of a review paper titled “Uncovering the role of chemical pollutants in shaping biological invasions.” The review was published Oct. 22 in Proceedings of The Royal Society B, the Royal Society’s flagship biological research journal.

Though there are many studies about how pollution and invasive species can affect ecosystems and the animals within them, few studies focus on how these phenomena may impact each other.

“There has been a lot of really good work on these interactions in plants, specifically in the context of how herbicide use may ‘open the door’ for introduced plant species,” Ligocki says. One possible mechanism involves herbicides weakening or killing some native plants, making it easier for invasive plants to find a foothold in new environments. “In contrast, there really hasn't been much work about these relationships in animals, which motivated us to write this review in the first place.”

In the context of the review, Ligocki and his collaborators define pollution as any synthetic compound released into the environment, such as fertilizer or pesticide runoff, microplastic waste and pharmaceutical waste. Pollution also includes naturally occurring compounds that are mobilized because of human activity, such as heavy metals or road salts.

The new paper also examines all kinds of animals, from mussels to mammals. Ligocki’s lab focuses on studying these questions in fish and amphibians.

Animals within the same species have different traits. Some individuals may be more aggressive or curious, or better at surviving the heat. Pollution could change which traits are most common within a species, which could then make that species better -- or worse -- at invading new environments.

For example, a risk-averse lizard might be likely to stay still and hide. As a result, it is more likely to remain undiscovered in cargo on a plane or ship and, ultimately, reach a new habitat undetected.

Pollutants could cause some lizards to move around less, increasing the number of individuals that are successfully transported on ships or planes. More lizards surviving the trip gives the species a better chance to establish a new population in a new environment.

Alternatively, chemical pollutants might interfere with the reproductive system of an introduced species and prevent them from successfully mating and populating the new environment.

“While we discuss many ways invasion success could be more likely as a result of pollution, there also are many ways invasion could be inhibited,” summarizes Ligocki.

Understanding the combined effects of pollution and invasives could inform more effective conservation and restoration plans, he adds.

For more information, email Ligocki at isaac.ligocki@uwyo.edu.