The northern Albertine Rift, in which the two parks sit, is one of the richest reserves of biodiversity in the world. It's also home to many charismatic wildlife species, including elephant, great herds of ungulates, and lion. But how many lions is poorly known, because the area's intense poverty and strife have made it dangerous to carry out ground surveys of the cats, which can't be easily spotted from the air.
What can be readily seen and counted from planes, though, is the lion's prey. Thus, Treves and his colleagues rounded up data from aerial surveys of buffalo, warthog, waterbuck and other ungulates, and plugged it into a model that uses prey numbers and size to predict the abundance of lions. Because ground surveys of the cats were conducted in QENP in 1999 and 2004, the researchers were also able to confirm that their predictions for the Ugandan park matched well with actual lion numbers.
PNVi consistently held four to five times less prey than QENP presumably due to poaching and habitat loss suggesting it can currently support fewer lions. Still, the researchers expect that if prey abundance rebounds and the Congolese park can sustain similar densities of lions as its Uganda counterpart, the entire region could hold up to 905 of the cats.
But actual lion abundance in QENP also revealed a disturbing trend: A 50 percent decline between 1999 and 2004, even though prey numbers rose by 7 percent over the same period. And if lions disappear, as some are forecasting, the entire ecosystem could be in peril, says Treves. Past research shows that loss of a top predator can trigger a cascade of unpredictable changes and completely transform the system.
Still, he's optimistic this won't come to pass, so long as immediate conservation interventions are taken. He hopes the paper will serve as a call to action.
"I don't want to see
|Contact: Adrian Treves|
University of Wisconsin-Madison