Computer models from the University of Chicago and Argonne National Laboratory indicate that climate change could exacerbate the impact of invasive species on North American forests. The study, published in Nature Climate Change, suggests that rising temperatures and drier conditions may hinder a fungus that controls the spread of the spongy moth, a pest responsible for extensive forest damage.

Greg Dwyer, Professor of Ecology and Evolution at UChicago and senior author of the study, highlighted the complexity of climate change effects on ecosystems. "The vast majority of previous climate change studies look at individual organisms, but a small amount of climate change can have a big effect when you compound it across multiple species," he stated. He emphasized the role of computer models in understanding these interactions.

The spongy moth (Lymantria dispar), introduced to New England's hardwood forests in 1869, has caused significant defoliation by feeding on tree leaves. A fungus known as Entomophaga maimaiga began controlling its population in 1989. However, this control depends on cool and moist conditions. "Even small reductions in mortality rate for the moths lead to big increases in defoliation," Dwyer explained.

Dwyer's research has focused on modeling interactions among species and diseases since 2004. In collaboration with atmospheric scientists Jiali Wang and Rao Kotamarthi from Argonne National Laboratory, his team integrated precise climate data into new models predicting spongy moth infestations.

Their findings suggest that hotter and drier climates will reduce fungal infection rates over time, leading to more moths surviving to damage trees. Recent weather patterns have already led to increased outbreaks earlier than expected. "Our projections were pessimistic, but probably not pessimistic enough. It’s very concerning," Dwyer remarked.

The study involved contributions from Colin Kyle and William Koval from UChicago, Vanja Dukic from the University of Colorado Boulder, with funding from the National Science Foundation.