ISLE ROYALE - Over the 50 years of the Isle Royale Wolf/Moose Study, four types of observations have been constant.
Wolves always get counted. So do moose.
The other three constants are monitoring predation rate, performing autopsies of moose kills and collecting skeletal material.
"The data collection can't stop, that always comes first," study co-director John Vucetich said.
But as the study passes the 50-year mark, researchers are looking at new aspects of the island's wolf/moose population.
"We have been monitoring ticks on the moose for the last three or four years," Vucetich said. "The hypothesis is that the ticks could have a huge impact on the moose population dynamics."
Study co-director Rolf Peterson said the winter tick likely came to the island on the backs of the moose, which swam to Isle Royale in about 1900.
In more recent years, the ticks have developed into a serious problem for the moose. As many as 80,000 ticks can cover a single moose.
The ticks feed in the winter. They can consume enough blood to force the moose to regenerate its entire blood supply during the time of year when food is most scarce.
Climate change is making matters worse for the moose. According to data on Vucetich's Web site, www.isleroyalewolf.org, five of the last six summers have been the hottest in the 50-year history of the study. This warming trend is likely to favor ticks.
The scientists are also looking at the impact warmer summers are having on the moose independent of winter ticks.
Warm summers reduce moose's ability to feed, Peterson said.
"They don't perspire, they don't have any way of getting rid of heat, so they just have to rest in the shade or get in the water and they can't be active," he said.
Inability to eat aggressively in the summer leaves the moose with less stored energy to survive the winter.
An aspect of the wolf population the scientists are paying more attention to is genetic diversity.
"Wolves on Isle Royale are extremely inbred," Vucetich said.
All of the wolves on the island are descended from a single breeding pair. Every wolf is as closely related to every other wolf as brother and sister, giving rise to questions about the possibility of inbreeding depression in the population.
Peterson said spinal deformities have been evident in wolf skeletons for some time.
"In the last 10 years, we haven't had a normal one," he said.
But by other indications, such as birth rates and mortality rates, the wolves are doing just fine.
"These are very successful wolves by any measure," Vucetich said.
There has not been a lot of research on the impact of inbreeding on wolf populations.
"There are some studies of captive wolves that shed some light on it, but that's not the same thing as having a living, breathing population out here interacting with their prey," wolf biologist Dave Mech said.
Mech was the first field researcher to work on the Isle Royale Wolf/Moose Study and is a renowned wolf expert. He was on Isle Royale over the weekend for the study's 50th anniversary celebration.
Genetics may or may not cause problems for the wolves on Isle Royale, but they have provided scientists with a new tool for studying them.
Laboratory scientists can now extract DNA from wolf scat and use it to determine a variety of population demographics. Previously, the researchers working on the study extracted DNA only from the wolves captured for radio collaring. One wolf in each pack gets a radio collar.
Using DNA from scat, scientists can identify individual wolves and determine their sex. Neither can be done reliably from an airplane, which is the usual vantage point from which wolves are observed on Isle Royale.
"What we're doing now is we have an individual fingerprint for every single wolf so we know how long a wolf is living in a population, when they are born, when they die," Leah Vucetich said.
Leah Vucetich, who is John Vucetich's wife, is a research assistant professor at Michigan Technological University. She has been studying Isle Royale wolf genetics for several years.
At a laboratory in Tech's Noblet Forestry Building, there is a catalog of wolf scat samples going back to before 2000. The scat contains genetic data that will determine, among answers to other questions, which wolves established Paduka Pack, a new pack first observed on the island in January.
DNA from moose scat is useful, as well. It offers information related to the population's reproductive rates and genetic diversity.
Dan Schneider can be reached at dschneider@mininggazette.com