Brown University, National Park Service scientists team up to unlock insights into foraging habits in Yellowstone.
Ecologists have long sought clarity on the dietary habits of different animal species. For biologists at Brown University and the National Park Service, it wasn’t obvious how herbivores in Yellowstone National Park, who subsist on grasses, wildflowers, and trees, could compete for enough of those foods to survive the winter.
Over two years, with the aid of cutting-edge molecular biology tools and GPS tracking data, the researchers were able to determine not only what herbivores in Yellowstone eat, but also what strategies the animals use to find food throughout the year. The team published its findings in Royal Society Open Science.
“In Yellowstone, we know vegetation changes across seasons, but until now, we didn’t know how these seasonal changes influenced what animals eat or how they sustained themselves when options were limited,” says lead study author Bethan Littleford-Colquhoun, PhD, a postdoctoral research associate at Brown. “It turns out that while species eat similar categories of food, their diets differ from one another in cryptic and nuanced ways. And an animal’s body size plays an important role in how this is achieved.”
For decades, ecologists have debated how wildlife should confront challenges with their food supplies, says co-author Tyler Kartzinel, PhD, an associate professor of ecology, evolution, and organismal biology.
Some experts argue that animals should diversify their diets to satisfy their taste preferences when they have the most freedom to select their favorite foods in summer, Kartzinel says. Others have posited that animals should diversify what they eat when they’re forced to accept whatever happens to be available—such as in a hard winter when they may have to compete for even undesirable foods to survive.
“These opposing predictions couldn’t both be true, so it wasn’t at all clear how Yellowstone’s assemblage of herbivore species—with such a diversity of foraging behaviors—could succeed in finding enough food throughout the year,” Kartzinel says.
