Researchers studying the European bison in Romania have found that the large herbivore could be a useful tool in the fight against climate change. Scientists at the Yale School of the Environment have developed a new model that suggests that a herd of just 170 bison might store enough carbon dioxide (CO2) to take nearly two million cars off the road for an entire year.

The study highlights how important wildlife conservation is to maintaining the health of ecosystems, although it has not yet been subjected to peer review. The model considers how animals like bison, through their natural behaviors, contribute to the uptake and storage of CO2 in the soil.

The lead author of the study, Yale Professor Oswald Schmitz, was cited by The Guardian as saying that bison “influences grassland and forest ecosystems by grazing grasslands evenly, recycling nutrients to fertilize the soil and all of its life, dispersing seeds to enrich the ecosystem, and compacting the soil to prevent stored carbon from being released.”

He went on to say that because these animals—the European bison—evolved over millions of years alongside the ecosystems of grasslands and forests, their eradication has caused enormous carbon emissions, particularly in areas where grasslands have been cleared for development. Professor Schmitz continued that “rewilded” bison are among the climate heroes who can restore these habitats and help restore balance.

Nearly 200 years have passed since the European bison vanished from Romania, but in 2014, WWF Romania and the nonprofit organization Rewilding Europe brought the animals back to the southern Carpathian mountains.