The long-term problem of habitation degradation will be difficult to solve, according to Haydon.
"Population pressures in these areas are only going to get worse," he said. "Livestock graze higher and in ever greater numbers, and the effect of livestock grazing on the wolf's food supply, the rodents, is largely unexplored at the moment. But it's likely to be serious."
Fatal canid diseases present a more immediate—and more addressable—threat to the wolves.
Wildlife managers have effective rabies vaccines that can address the problem, but there are complications.
Ethiopian wildlife officials have yet to approve the use of oral rabies vaccines, which are cheap, effective, and widely used in Europe and the United States, Haydon says.
As a result, wildlife managers must trap and sedate Ethiopian wolves individually and vaccinate them by hand during rabies outbreaks—an expensive and time-consuming process.
A further consideration is what immunization strategy to employ. Blanket coverage—immunizing most vulnerable individuals—aims to stamp out a disease entirely.
But the approach is just not practical for Ethiopian wolves, according to the study authors.
"Theoreticians have devoted a lot of effort to working out how to vaccinate populations in ways that prevent epidemics getting started, but this requires coverage that is impractical in wild populations," Haydon said in a press statement.
During the 2003 rabies outbreak, staff with the Ethiopian Wolf Conservation Program and the Frankfurt Zoological Society launched a more targeted vaccination program: Wolves in adjacent mountain valleys were immunized to slow the spread of the disease from infected wolf packs.
The study team plugged extensive population data—some of it gathered during the 1993 and 2003 rabies outbreaks—into ecological and epidemiological models. The researchers' analysis led them to conclude that such targeted immunizations can prevent major die-offs in wild Ethiopian wolves.
"We've looked at vaccination studies that don't prevent all outbreaks but do reduce the chances of really big outbreaks—ones that could push an endangered population over the extinction threshold," Haydon said.
"These strategies turn out to be effective and a lot more practical."
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