The passage of an ice bridge between Canada and an American island, by a solitary wolf made it possible to regenerate the genetic pool of the local pack but also an entire island ecosystem, conclude American researchers after years of study.
“This is the first study to show that genetic issues not only impact a given population and increase the risk of that population becoming extinct, but also have broad implications for all species,” explains to AFP Sarah Hoy, lead author of this study published Wednesday in the journal Science Advances.
The team of this ecology researcher at the Michigan Technological University scrutinized the ecosystem of Isle Royale, located on the American side of Lake Superior, a vast expanse of fresh water wedged between Canada and the United States. States, after the arrival on site of a lone wolf unknown to the local pack.
In 1997, this newcomer, dubbed “M93” in the context of the study but more affectionately “the old gray wolf” by the researchers, crossed an ice bridge between Canada and the island.
The first known wolves had arrived in this territory in the 1940s and they mainly hunted moose, thus making it possible to carry out the longest study ever carried out on the “predator-prey” system.
In the 1980s, the introduction of a virus, the “canine parvovirus”, in this ecosystem contributed to decimating the local population of wolves which fell from fifty to a dozen, underlines the study.
New breeding male
But the arrival of the “old gray wolf” changes the situation for the local packs and the whole ecosystem. Not being linked to this pack and being particularly large, a key advantage against the elk, he has established himself as the new “breeding male” among one of the three packs on the island, to the point of being the parent of 34 Cubs.
As a result, not only is the gene pool of the island’s wolves diversifying, but their ability to kill moose is improving.
A wild moose, the main prey of wolves, in Canada in 2019
AFP/Archives
As elks, herbivores, eat up to 14 kilos of vegetation a day, the reduction in their number in the face of wolves also leads to a transformation of the ecosystem to restore its balance, conclude the American researchers.
With fewer moose, the balsam fir trees began to grow again at a rate not seen in decades, which was vital to the forest and therefore a myriad of plants and species.
But the story does not end there and the wolf population boom eventually contributed to a new imbalance in the ecosystem, due to inbreeding.
After the death of “M93”, which had given its gene pool to about 60% of the wolves, the population began to decline again to the point where only two wolves remained: a father and his daughter, who was also half- sibling.
A reintroduction program for the species launched five years ago has, however, restored a better balance in this isolated ecosystem where around thirty wolves now live and just under a thousand elk, also called “moose”. in North America.
For Sarah Hoy, the case of the “old gray wolf” could undoubtedly apply to other populations of inbred predators in danger of extinction such as cheetahs by showing that the introduction of one or a few individuals into a gene pool not only renews a population but also an ecosystem.
Professor of ecology at Oregon State University, William Ripple describes as “important” the work of his colleague from Michigan, in which he did not participate, by showing that genetic processes can limit the ecological impacts” of a given species, he told AFP.
2023-08-23 20:53:10
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