These three wolves are the last three native wolves living on Isle Royale, researchers say. Courtesy of Michigan Technological University.
LANSING — It appears the worst predictions are coming true for the wolf population on Isle Royale.Michigan's only national park, once home to a thriving wolf population, appears to have just three wolves remaining on the island, according to the 57th annual Winter Study from Michigan Technological University researchers.
It's a sharp drop from the nine wolves observed during the last Winter Study.
John Vucetich, an associate professor of wildlife ecology, said wolves are likely to disappear completely from the island. "There is now a good chance that it is too late to conduct genetic rescue," Vucetich said in a statement.
The Winter Study also observed about 1,250 moose and two wolves that visited the island, coming and going over an ice bridge on Lake Superior. Vucetich works with Rolf Peterson, research professor at Michigan Tech.
It's unknown exactly what happened to the six other wolves that were on the island during last year's study. It's possible some may have left on an ice bridge that persisted after last year's study. At least one wolf died. With wolves at an unprecedentedly low level on the island, the gap between moose and wolf population continues to grow. This could mean bad things for Isle Royale's vegetation.
The researchers pointed to 1996, when moose population boomed, as a possible example of what could happen if moose population continues to rise. "At that time the moose population had considerable impact on forest vegetation," the report states. "Concerns remain that the upcoming increase in moose abundance will result in long-term damage to the health of Isle Royale's vegetative community."
Researchers observed just one moose killed by wolves on the island during the 19-day study, the fewest in the study's history. Despite the presence of the visiting wolves, which were on the island for less than a week before traveling back toward the U.S.-Canadian mainland, it's uncertain if those wolves came across the three native wolves. The wolves native to the island mainly kept in the northeast portion of the island, while visiting wolves traveled in the middle of the island and the southwest end.
The researchers say new genes from wolves like the two that briefly appeared on the island are desperately needed in the remaining pack on the island. Inbreeding among Isle Royale wolf packs has greatly contributed to the decline in wolf population on the island.
For instance, in the remaining pack, the two adults appear to be healthy. However, the third wolf, a nine-month-old pup, has a constricted waistline, hunched posture and a deformed tail. "Those observations suggest that the pup is not well off," Vucetich said. "It would not be surprising if the pup was dead a year from today." The report stated on the last day of the study, Peterson had found the two adult wolves, but not the pup.
There are only two options on what to do about Isle Royale's wolf population, according to the report.
One is reintroduce wolves to the island to get more genetic diversity among the wolf population and encourage healthier breeding. The other is to simply do nothing and let nature take its course.
But, Peterson questioned if humans have already tampered with nature's processes to help cause the decline of wolves on Isle Royale. He pointed to the less frequent formation of ice bridges in winter from the mainland to the island, which used to allow new wolves to bring their fresh genetics to Isle Royale. "One must use the word, 'naturally', carefully these days," Peterson said. "The human imprint is written all over the dynamics of this wolf population in recent decades".
•Read the full report here.