For decades, ecologists have theorized that the extinction of one important species could set off a chain reaction of losses throughout an ecosystem. Now, new research offers some of the clearest real-world evidence that this idea of coextinction is not just theoretical.
The study, led by Princeton University doctoral student Finote Gijsman and co-authored by University of Florida Professor Todd Palmer Ph.D., found that African elephants function as a keystone species for dung beetles across Kenya's savannas. When elephants were removed from experimental landscapes, dung beetle populations collapsed, along with critical ecological functions those insects provide.
"So, losing elephants doesn't just mean losing elephants," Palmer said. "It means losing a significant fraction of dung beetle diversity and the ecosystem functions that go with them."
Palmer and his collaborators published their study May 28 in the journal Science.
Dung beetles may not receive the same attention as elephants, but they play a major role in maintaining a healthy ecosystem. By feeding on and burying animal dung, the insects recycle nutrients, disperse seeds, improve soil quality and suppress parasites. According to the study, the value of these services to the U.S. and U.K. cattle industries alone is estimated at roughly $1.6 billion in 2026.
To understand how strongly beetles depend on large mammals, researchers first tested which types of dung attracted the greatest diversity and abundance of beetles. Elephant dung overwhelmingly dominated the results, drawing far more beetles than dung from any other species.
"Elephants are clearly the most connected, most important node in the whole network," Palmer said. "They feed for up to 18 hours per day, during which time they eat about 300 pounds of food and excrete up to 200 pounds of feces per day."
The next phase of the project relied on a massive long-term ecological experiment Palmer and collaborators established at Kenya's Mpala Research Center in 2008.
Known as the UHURU experiment, the site contains a series of large, fenced plots that selectively exclude mammals by body size. Some plots exclude only the largest herbivores, including elephants and giraffes, while others exclude smaller animals like duikers and dik-diks. Additional plots remain open as control groups. This design allows researchers to simulate extinction patterns that often affect large animals first.
Fifteen years later, the UF-supported experiment has become one of the world's most influential long-term studies of African savanna ecology.
"Large mammals are the most extinction-prone, because they have big home ranges, meaning they come into contact with humans and human-related stuff like roads most often, big energy requirements and relatively slow rates of reproduction compared to the smaller stuff," Palmer said.
Researchers found that plots without elephants contained 67% fewer dung beetles, 51% less beetle biomass and 23% fewer beetle species.
"Interestingly, the 23% species loss matched almost exactly what computer simulations of the biggest mammal's extinction predicted. Excluding all the other large herbivores on top of that made almost no additional difference… it really was about elephants specifically," Palmer said.
The loss of beetles also altered how the ecosystem functioned. In elephant-free plots, dung decomposition slowed, and seed dispersal declined. Because of this, Palmer said this research reframes how we think about the conservation value of species.
"Elephants are charismatic and there is lots of focus on their conservation, but primarily for their own sake," he said. "This paper adds a new argument, showing that elephants are infrastructural. Their dung subsidizes an entire community of insects that collectively perform services worth billions of dollars annually."
Beyond its ecological findings, the study also demonstrates the value of large-scale, long-term research projects, according to Palmer. Many ecological studies last only a few years, but Palmer said some of the most important patterns in the UHURU experiment emerged only after more than a decade.
"The 15-year exclosure experiment at Mpala is about as close as field ecology gets to a controlled extinction experiment, and the fact that the real-world outcomes matched the network simulations so precisely is really cool," Palmer added.
