This Cat Holds Ecosystems Together
Pumas play an invisible but essential role in linking hundreds of species.
Posted January 28, 2022 | Reviewed by Davia Sills
- Pumas maintain ecological interactions with at least 486 other species throughout their range in the Western hemisphere.
- Pumas impact some species directly by feeding on them and others indirectly through fear effects and carrion provisioning.
- Humans benefit from ecosystem services provided by pumas, resulting in fewer deer-vehicle collisions.
According to a new analysis, pumas maintain relationships with nearly 500 living species and play an integral role in keeping ecosystems healthy and resilient throughout the Western hemisphere. The study, published in Mammal Review, is the result of a collaboration between the conservation organizations Defenders of Wildlife and Panthera.
Lead author Laura LaBarge, a postdoctoral researcher at the Max Planck Institute of Animal Behavior in Germany, says that this study not only demonstrates how pumas link numerous animals and plants but also how the human communities tied to these ecosystems benefit from the big cats.
“We hope this awareness of how important pumas are to ecosystems, as well as how having wild pumas around helps people, could persuade the public that pumas are worth conserving and we should invest in strategies that allow them to coexist with us,” she says.
A cat with connections
Pumas (Puma concolor) go by many names, including mountain lions, cougars, catamounts, and Florida panthers. They are the fourth largest cat in the world and have the widest distribution of any mammal in the Western hemisphere, inhabiting land from the Canadian Yukon to the southern Andes in South America. Across this range, they live in a variety of habitats.
Due to their wide range and adaptability, LaBarge and her colleagues suspected that pumas interacted with many other species. But no one had systematically evaluated the evidence for all of the puma's purported ecological roles.
For the new study, the research team reviewed thousands of papers and ultimately found 162 published between 1950 and 2020 that focused on puma interactions and their impact on ecosystems.
The researchers identified 203 species as puma prey, 281 species that feed upon puma prey in scavenger communities, and 12 species as puma competitors.
Indirect ecosystem impacts
“Large predators like pumas play outsized roles in the ecosystems in which they live, usually by hunting prey,” LaBarge says. “But their presence also has a variety of strong but indirect effects on those ecological communities.”
For instance, prey brought down by pumas support hundreds of other species. Pumas are capable of killing prey larger than themselves and lose large amounts of food to competitors like dominant carnivores and scavengers. Mark Elbroch, the senior author of the study and Panthera’s Puma Program Director, says that pumas can have about a third of their food stolen from them.
“That food is providing a large amount of carrion to the ecosystems in which they live, which has numerous cascading impacts,” he says.
One study conservatively estimated that pumas contribute 1,507,348 kg of meat per day to scavenger communities throughout their range in North and South America.
Another indirect way that pumas can impact ecosystems is through fear.
“Animals like deer in North American temperate forests and vicuñas on the plains of Patagonia tend to avoid places on the landscape where pumas can use cover to ambush them and concentrate their browsing in relatively safer locations,” says LaBarge.
These changes in landscape use may ultimately affect plant diversity, as well as smaller species dependent on plants. LaBarge, Elbroch, and their colleagues found 22 species that indirectly benefitted from fear effects induced by pumas, including plants, small vertebrates, and insects.
The researchers also sifted the literature for studies of ecosystem services that pumas provide, defined as benefits supporting human economies, health, and well-being. While they found only a small number of studies that examined this explicitly, there is evidence that pumas make good neighbors.
For instance, by feeding on prey such as deer, pumas may mitigate collisions with vehicles and therefore reduce human injuries, fatalities, and associated economic costs. The recolonization of pumas in North Dakota is estimated to have reduced the costs associated with deer-vehicle collisions by over $1 billion. Scientists estimate that recolonization of the eastern U.S. by pumas could reduce deer-vehicle collisions by 22 percent over 30 years, averting 21,400 human injuries, 155 human fatalities, and over $2 billion in costs.
Ultimately, LaBarge, Elbroch, and their colleagues would like this study to inform more strategic investment in the protection and restoration of puma habitats and populations. In addition, they hope their findings help make the case for the benefits of puma conservation to the general public.
Like many large carnivores, pumas are often in conflict with people. They are legally and illegally hunted because they compete with humans for prey and other resources and because they pose perceived threats to people, pets, and livestock. Throughout their range, they face threats including unregulated hunting and poisoning, retaliatory killing, habitat fragmentation and loss, and vehicular collisions.
Elbroch says that in the case of pumas, humans impose the carrying capacity. “The number of mountain lions in a system has nothing to do with the available resources,” he says. “It has everything to do with how many we will allow to live there.”
Still, Elbroch and his colleagues are hopeful that evidence of pumas’ importance to natural and human communities will help people become more tolerant of the animals and even supportive of conservation efforts.
“Clearly, these are important animals in the ecosystem,” Elbroch says. “As they increase the health, resilience, and diversity of an ecosystem, they also support healthy human communities.
“We found evidence that it is worth being a human community that lives side-by-side with mountain lions.”
LaBarge, LR, Evans MJ, Miller JRB, Cannataro G, Hunt C, and Elbroch LM. Pumas Puma concolor as ecological brokers: a review of their biotic relationships. Mammal Review. Published online 18 January 2022. Doi: 10.1111/mam.12281.