The rapid, low-cost technique is the first to analyze DNA left behind in animals’ feces to map out complex networks of species interactions in a terrestrial system. It could help redefine conservation as we know it, identify otherwise hard-to-find species and guide a global effort to rewild vast areas.
“It’s not just that we can rapidly capture the biodiversity of an area,” said study lead author Jordana Meyer, a biology PhD candidate in the Stanford School of Humanities and Sciences. “We can also quantify the extent of indirect links among species, such as how a specific predator’s behavior affects vegetation in an area. This allows us to measure impacts on species that are essential to the system or particularly vulnerable.”
Working at Stanford’s 1,193-acre Jasper Ridge Biological Preserve, the researchers used their technique to analyze feces from carnivores such as mountain lions, omnivores such as gray foxes and herbivores such as black-tailed deer. By identifying the DNA in the diets of these animals, the researchers constructed an extraordinarily detailed, data-rich food web and accurately captured the biodiversity of the area when compared against other animal surveys and a long-term camera trap study in the preserve.
“We are excited about this approach because it will not only help us to understand how and why species survive in protected areas based on what they eat, but also whether animals are able to capitalize on non-native plant and animal species,” said study senior author Elizabeth Hadly, the Paul S. and Billie Achilles Professor in Environmental Biology in Stanford’s School of Humanities and Sciences. Hadly’s lab has pioneered work with left-behind and ancient DNA in the U.S., South America and India.
The researchers plan to scale-up their model across protected areas in Africa to assist in strategic adaptive management and rewilding strategies. “I am hopeful that techniques like this can help us secure and monitor natural spaces on a global scale,” Meyer said.