While the moose population at Isle Royale National Park in Michigan is estimated at 1,300 animals, up from just 540 in 2005, the island's wolf population stands at just two, according to a winter survey of the park by Michigan Tech University researchers.
"The 2016 Winter Study observed the tracks of two wolves on the island, down one wolf from the previous year," a park release said. "The two remaining wolves are believed to be animals that share a common mother and the remaining female is the daughter of the remaining male, suggesting significant impediments to reproductive success. These wolves are estimated to be 6 and 8 years old, respectively."
Chronic inbreeding appears to have impacted the health of the wolf population. There was hope that "ice bridges" that formed between the Lake Superior island and the Canadian mainland during the winter of 2013-14 would enable wolves to arrive from Canada with new genes. But no new wolves reached the island, while one female left and was killed by a gunshot wound in February 2014 near Grand Portage National Monument in Minnesota.
Isle Royale wolves have been in decline for more than a decade. In recent years park managers have discussed island and wolf management with wildlife managers and geneticists from across the United States and Canada and have received input during public meetings and from Native American tribes of the area. Those discussions have examined the question of whether wolves should be physically transported to Isle Royale, in large part due to concerns that a loss of the predators would lead to a boom in the moose population that likely would over-browse island vegetation.
Park officials currently are preparing an environmental impact study on whether to physically bring wolves to the island in a bid to rebuild the population and its genetic diversity.
Moose, meanwhile, have undergone population swings in recent years, shifts that biologists attribute to "changes in forest type, weather severity, disease, and changes in predation pressure."
"The moose population was at an all-time low in 2005 with 540 animals. MTU scientists concluded that the declines were likely associated with 'Climate warming and increased ticks…' which in turn were thought to result in low levels of moose recruitment (birthrates)," the park's release said. "Forest succession might also explain some of the decline.”
Since that time, however, the moose population has boomed to an estimated 1,300 this year (+/-390 individuals).
"Dr. Rolf Peterson was able to note a higher percentage of twin calves in this year’s study, predicting that it may bolster the population," the release added. "Twins are normally a result of moose being well nourished and exposed to limited predation stresses. The survey data on moose shows that the population is still on the increase; however, this is a different trend than what is being found in Minnesota and suggests that there could be differing factors impacting moose at the park than on the mainland."
Also of note from the past winter's survey was that the island's tick infestation has declined since peaking in 2007.
"Tick abundance fluctuates with weather conditions, and declines were observed with the cold, long-lasting winters of 2013 through 2015," the park release said.
Comments
So once again "97% of the scientists: were wrong.
Not sure that's an accurate conclusion, EC. Part of climate change is increased vagaries of "weather," so what's transpired the past 15 years would fit into that.
But that hasn't happened. Another wrong projection.
Heard an interesting discussion yesterday about the concept of something being "provably false". There is "rule" in science that if a theory can't possibly be proven false then it isn't a valid theory. The Climate Change theory fits this perfectly. If it warms its due to climate change, if it cools its due to climate change if there is more violent weather, less violent, more rain, less rain, ..... it is due to climamte change. Since every possible outcome is attributed to "climate change" (after the fact) there is no way to prove it false and therefore the whole theory is invalid. The reality is that the predictions of climate change theorists have been horribly and repeatedly wrong.
No vagaries in the weather around Isle Royale? Warmer in the early part of this century, then a cold winter or two that led to an ice bridge, then warming again...
What would be good to see, and I'm sure it's out there somewhere, are weather records that show the average winter/summer temps for the past 50 or 100 years.
Weather indeed fluctuates but those fluctuations have been no greater than in the past despite the climate change predictions.
I would be in favor of introducing new wolves to the park right away. For the following reasons (in brief)
Science Research Opportunities
Can the wolf population be "saved" from the inbreeding that has caused the depletion of the popluation by introducing non related wolves to the island.
Will the non related wolves breed with the inbred wolves, or will they "sense" they are unhealthy?
What can we learn from reintroducing non related wolves to the population on Isle Royale that could be applied to other situations where a breeding population has become isolated and inbred?
Environment
Continue to attempt keep a balanced eco system for the flora/fauna of the island
Tourism
People have come to the island in hopes of seeing wolves and for the unique hiking and observation of wildlife the island offers. Without the wolves......
Future
Maintain the genetic diversity, not only of the wolves but of the other wildlife if it continues to be isolated. Perhaps a program that swaps some individuals every year?
Questions to mull and spur further comments, mgarn:
* How does artificially introducing wolves to the island affect the scientific study of the prey-predator relationship? Would it be better to let the wolves die off and see how the moose population fares? Would that be more scientific than artificially introducing more predators?
* Should the NPS become, in effect, zookeepers charged with maintaining a set number of species and wade in when things get out of balance?
I agree that the NPS should let nature play out, especially in regards to a species that made it to the island as an opportunist. By all means they should study the relationship between predator and prey, but it's evident that the park will have to continually perform "genetic" rescues in perpetuity especially with an ice bridge that forms more and more infrequently.
I do know that the park service performs genetic rescues by crossing the genes of certain fish species that now have barriers due to dams. They play a role by moving a few species across the rivers and placing them in their key habitats and that keeps the species from becoming inbred. However, I think it's one thing if it is a human made dam that is blocking the natural flow of genes, yet, an ice bridge to an island that is being influenced by a warming climate is kind of stretching that line. While the climate is definitely in a warming cycle and that is one of the main reasons the wolves are not naturally recolonizing the island, I still think National Park Service biologists should play more of a monitoring role that studies the natural ebbs and tides of the landscape, instead of becoming a manager that influences ecosystems. I think it's one thing if a non-native species from asia or another distant location is unnaturally introduced and that wrecks the environment of a park and so the park system steps in to try and minimize the damage. But when a localalized opportunist establishes territory in an area, yet over the long term (in this case just a few decades) fails to maintain a population, I don't think makind should step in. If the moose population gets too high, ticks, starvation and disease will step in. That process is a part of nature too.
And whose to say, in another 2 decades or more, even the moose population collapses due to inbreeding without having an ice bridge that influences fresh genes flowing in when the opportunity presents itself. It does present an interesting case study on what happens on island habitats that are left to natural processes.