Pumas are unlikely to recolonize much of their historical range in the eastern U.S., a new study finds. It’s not a lack of habitat or food keeping out the pumas, also known as cougars or mountain lions. It’s the highways.
Historically, pumas (Puma concolor) ranged coast to coast across nearly all of the Americas, stretching from the northern reaches of Canada, down through the U.S. Rocky Mountains, and into South America from the Amazon Rainforest all the way south to Patagonia. But by the late 1800s, a combination of habitat loss and hunting wiped them out from the eastern half of the U.S.
Researchers used a model to predict where pumas might expand their range in North America this century. They used observational data on movement, population and survival of the animals to predict the areas in which the carnivores would be able to successfully establish a breeding population.
The study’s model predicted that pumas are likely to reclaim just 2.1% of their North American historical range by 2100, mostly in boreal Canada. A few western states in the U.S. could also see some new pumas, but they won’t move farther east. Hunting in western states is part of the problem, but the lion’s share of the issue is a combination of human development and highways that create a fragmented landscape that pumas simply can’t break through, the study found. An earlier study found one to two pumas are killed on highways each week in California alone.
Pumas are listed as a species of least concern on the IUCN Red List. They’re not at risk of extinction as a species, but they’re not performing their ecological function for roughly half the U.S., researchers say.
Pumas are crucial for healthy ecosystems and forest resilience, Mark Elbroch, co-author of the study and puma program director with global wildcat conservation NGO Panthera, told Mongabay by phone. He added a population of pumas could reduce car collisions with prey animals like deer, and there’s evidence that pumas could reduce the transmission of diseases like chronic wasting disease and perhaps Lyme disease. Nearly half a million people are treated for Lyme each year in the eastern U.S.
There have been sightings of pumas in the eastern U.S., but Elbroch said genetic testing shows most of those animals are from South America, likely pets released into the wild, not western cougars that trekked east. Furthermore, individual pumas are likely solitary males looking for a new territory, not evidence of a breeding population. Females tend to stay within 10 kilometers (6 miles) of their natal range, he said.
Elbroch added the only way to establish a breeding population of pumas in the east is to reintroduce them. “If we are going to wait, we’re going to be waiting a long time. Our research suggests that within 70 years we’ll just see them getting to the Great Lakes,” he said.
Banner image: Rhett A. Butler.
Credits
