Natural History

From the BBC:

Populations of the world’s rarest dog, the Ethiopian wolf, are genetically fragmenting, scientists say.

Fewer than 500 of Africa’s only wolf species are thought to survive.

Now a 12-year study of Ethiopian wolves living in the Ethiopian highlands has found there is little gene flow between the small remaining populations.

That places the wolves at greater risk of extinction from disease, or habitat degradation.

In a study published in the journal Animal Conservation, Dada Gottelli of the Zoological Society of London and colleagues in Oxford, UK and Berlin, Germany, quantified the genetic diversity, population structure and patterns of gene flow among 72 wild-living Ethiopian wolves.

The team sampled wolves living within six of the remaining seven remnant populations, as well as from one population at Mount Choke, that has since become extinct.

They found that genetic diversity was relatively high for a species that has declined to fewer than 500 individuals.

That may be because discrete populations of wolves survived in Africa after the last glaciation period, which ended 18,000 years ago, and a number of rare gene types became fixed and maintained in these separate groups.

However, this isolation is now working against the wolves.

Researchers studied gene types at 14 separate locations on the wolf genome. They found that there is now weak gene flow between the Ethiopian wolf groups.

There is very little that actually can be done to save Ethiopian wolves. If Ethiopia would create massive corridors between wolf populations, they might stand a chance.

However, this species is unusually habitat specific. They may have once been quite wide-ranging over Ethiopia, and they once may have had a more eclectic diet.

But the only populations that remain are in the Ethiopian Highlands, and these animals live almost entirely on rodents.

Unlike any other Canis species, this one has become specialized to a particular habitat, and this habitat is simply not fairing very well with climate change.

Now, this is an intelligent animal, and they might be able to adapt to a more diverse diet and to a different habitat.

But “might” doesn’t mean that they are.

And thus far, they have not shown any signs of adapting their diet or moving into different habitats. And in this case, they’re probably screwed.

These canids have maintained their genetic diversity because they reproduce via a pair bond, and they have inbreeding avoidance behaviors.

This may also explain why some Ethiopian wolves will try to mate with domestic dogs. They need new blood, and they’ll take it even from a domestic animal.

But the hybrids have been culled from the Ethiopian wolf population, probably unwisely. After all, both common wolves and coyotes have been found to have some domestic dog ancestry, and dog genes have not destroyed the wolf or coyote populations.

It’s also likely that Ethiopian wolves have always had some introgression of dog genes. After all, there was a very flawed mtDNA study that suggested that Ethiopian wolves evolved from common wolf ancestors 100,000. A more comprehensive DNA study found that they actually diverged from the other interfertile Canis 3-4 million years ago. That mtDNA study is why we call them “Ethiopian wolves” today, even though they are actually more genetically distinct from common wolves than golden jackals are.

I don’t have much hope for the Ethiopian wolf.

They are an interesting offshoot of the Canis lineage.

Who knows what these animals were like when they were once more widespread in Ethiopia?

They had to have been much more adaptable than they are now.

The common wolf is nothing like this animal.  From the swamps of Florida to the frozen wastes of Greenland and from the searing sands of Arabia to the Russian taiga, the common wolf has adapted to a wide array of habitats and prey species.

The common wolf is actually succeeding as a species. It is very unlikely that it will go extinct now..

But its cousin in Ethiopia, which has gone the route of specialization, is probably not going to make it.

Now, they might be able to maintain themselves as inbred population, but seeing as the species has retained quite a bit of diversity even though they are now rare, the species probably hasn’t evolved much inbreeding tolerance.

So they may not last if they have to continue through inbreeding.

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I have some little quibbles with the BBC piece. I mentioned one of them earlier.

The claim that Ethiopian wolves evolved recently from the common wolf is supported only through mitochondrial DNA studies, which are not the best tool for determining when species split from each other.

The other is the claim that common wolves and red foxes are habitat specific. They aren’t at all. Wolves in the New World were found from the swamps of Florida to Alaska and from the Valley of Mexico to Greenland. In the Old World, they were found from Senegal to Ethiopia and across the Middle East to India and Burma. They were found throughout Asia and all of Europe, including Ireland and Great Britain.

That’s not a habitat specific animal at all.

And red foxes are even less so. They are currently the most widespread of all wild carnivorans.

Finally, the claim that wolves don’t disperse far from their natal packs is not supported by the evidence. Wolves have been found traveling hundreds of miles from the packs in which they were born in search of new territory.

Ethiopian wolves may not exhibit this behavior, simply because they have become so specialized to the Ethiopian Highlands habitat.

And this area is quite finite.

And if the ecosystem of the Ethiopian Highlands continues to degrade due to overgrazing and climate change, they are fairly vulnerable.

And they likely won’t last long.