Looking for a home where the buffalo roam? Europe's Carpathian Mountains qualify, it seems, and they may one day host thousands of bison if researchers' findings are heeded.
A new study has found that the Carpathian Mountains, which run through Central and Eastern Europe, could harbor far more European bison than they do today. According to the findings, the mountains present the best hope for a population large enough to resist the many threats facing the recovering species, which was once extinct in the wild.
The European bison is a slightly smaller relative of the American bison. Like its American cousin, it was decimated by habitat loss and hunting in the 19th and early 20th centuries. The last wild European bison was poached in 1927. A few survived in zoos and fledgling breeding programs.
Today, there are about 3,000 European bison, all descended from just 12 individuals. About 1,600 of them are free-ranging wild animals.
"That's not a large number, but it's still a major success story in terms of conservation of wild animals," said Tobias Kuemmerle of the University of Wisconsin, Madison, who led the new study.
Despite growing numbers, the European bison is not out of the woods yet. The small herd sizes and inbreeding resulting from having so few founder animals make the bison highly susceptible to diseases or other dangers that could wipe out a whole herd at once.
"Though we have these free-ranging herds, they are probably in trouble if we do not allow them to grow and if we do not establish connectivity (among the herds)," Kuemmerle said.
For the population to be large enough to weather the sorts of random events that could sweep through and devastate the species, individual sub-populations should have at least 100 individuals. "There are only three herds that have that," he said.
"The small and isolated herds — most of these are not viable," agreed Rafal Kowalczyk who studies European bison at the Mammal Research Institute of the Polish Academy of Sciences in Bialowieza, where bison were first reintroduced to the wild. "They are too small to maintain genetic variation. They are much below the minimal population size. In the opinion of researchers, even a few thousand individuals are needed to really maintain the population."
Kuemmerle's study aimed to identify where an interconnected population of thousands of bison could fit and thrive in Europe. He gathered information about where the bison are succeeding today and overlaid these characteristics with information about what the habitat is like throughout these areas.
The resulting map showed a large region through the Carpathian Mountains of bison-suitable habitat. He and his colleagues published the findings in Biological Conservation.
"We kind of expected that there would be areas that are suitable that are not occupied, but what's really surprising is that there is so much of it," Kuemmerle said.
The decline of socialism has contributed to the large area. "One thing that happened is that vast areas of farmland were abandoned as people moved to cities or moved to the West," Kuemmerle noted. "There are many areas where human pressure is actually lower than it was during socialism."
"Taken together, that means there could really be a realistic chance that we could have the first meta-populations in the Carpathian Mountains in the future," he concluded.