Research published last month by scientists at the Voyageurs Wolf Project shows new data on how and where wolves in far northern Minnesota hunt their prey and how, in some cases, that hunting can have a profound impact on the region’s forests.
One builds on previous studies that demonstrated how wolves living in and around Voyageurs National Park eat gigantic numbers of beavers and, in doing so, can particularly shape the ecosystem by influencing the creation of wetlands.
The new findings estimate that wolves, by ambushing beavers as they move away from water in search of trees to eat, could also affect territory, changing the trajectory of about 3 percent of the boreal forest in the Voyageurs region.
Meanwhile, a second paper points to a strong link between human progression and where wolves actually hunted fawns. Reseek suggests that other people in northern Minnesota might inadvertently hunt wolves in their search for food.
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“When we put all the pieces together, it’s pretty transparent that the cumulative effects of all the major facets of human activity in the Northwoods — logging, infrastructure progress, and road and trail progress — have fundamentally replaced where and how wolves hunt calves. here,” said Sean Johnson-Bice, a PhD candidate at the University of Manitoba and one of the lead authors of both studies.
“The regulations of this predator-prey game change as humans adjust ecosystems, and it is conceivable that we have created situations that may have tipped the balance in favor of the predators. “
Over the past decade, researchers have combined state-of-the-art technology — GPS collars and surveillance cameras — with countless hours of sweaty studies in buggy boxes to better understand how wolves hunt during the summer months in northern Minnesota’s dense boreal forest.
Most previous studies on wolf predation have been conducted in winter, when wolves must track and hunt giant prey, such as deer, in packs.
Each spring, researchers attach GPS collars to a dozen wolves in their study area. The collars send a location signal every 20 minutes.
Whenever a wolf spends more than 20 minutes in one position, scientists come to investigate. They know it’s probably a position where the wolf ate something. They gather evidence as forensic pathologists and install surveillance cameras to help document long-term activities.
Over the years, they’ve discovered unexpected predatory behaviors, including wolves that hunt freshwater fish, gorge on berries and kill unexpected numbers of beavers, waiting, rarely for hours, to ambush beavers as they leave their ponds in search of food.
In a paper published earlier this month in the Proceedings of the Royal Society B, researchers found that wolves disproportionately kill beavers when they move away from the water, helping to keep the forest farther away from beaver ponds.
The study examines what happens to the surrounding ecosystem when the most sensitive predator, a wolf, encounters a beaver, a leading ecosystem engineer who shapes forests by cutting down trees and creates wetlands by damming streams.
Northern Minnesota beavers create a series of well-defined trails from the ponds where they live and walk those trails in search of food. And they can have profound repercussions on the composition of the surrounding forest.
Beavers prefer to eat deciduous trees, such as aspen, leaving evergreen conifers standing. Over time, as beavers eat more and more deciduous trees near water, this creates what are known as “coniferous halos” around the ponds, which are gently viewed from above.
In this study, the researchers found that the farther beavers moved away from ponds in search of food, the more likely they were to be killed by wolves.
They searched around 28,000 GPS clusters for the locations of 51 collared wolves, documenting around 2,000 wolf ambush attempts and more than 500 beavers killed by wolves.
“Basically, what they do, their mere presence and predation, is allow some forests to remain intact through beavers,” explained Tom Gable, a researcher at the University of Minnesota who leads the Voyageurs Project. Wolf.
For Gable, while it doesn’t show that wolves particularly modify forests on a giant scale, it does illustrate that wolves “are connected through predation to giant ecological processes. “And it shows how in the plant world, everything is, in one way or another. connected.
Scientists have also found that human movements can have an effect on where wolves hunt in northern Minnesota.
This is the conclusion of another paper recently published by several of the same authors in Ecoological Applications. There, the researchers documented how wolves use roads and trails to hunt fawns, that they hunt more in recently felled spaces, and that they hunt near homes and vacation spots where deer congregate.
In fact, the researchers found that the murders were much more likely to occur near buildings than in random locations in the woods.
“Surprisingly, wolves have a tendency to kill fawns closer to human infrastructure, such as cabins, permanent apartments and barns, than expected,” said Johnson-Bice of the University of Manitoba and co-leader of the study. ‘Study.
This location seems to contradict a long-standing theory called the “human hypothesis,” which states that prey congregates in close proximity to humans as a safe haven or safe haven from predators, to take advantage of the fact that top predators, including wolves, have a concern for humans.
“If we expected this to happen in our study area, we would have expected to find wolves killing deer more commonly away from infrastructure, but we found the opposite pattern,” Johnson-Bice said.
The researchers are quick to point out that there is no evidence that wolves in their domain near Voyageurs National Park have lost their concern for humans. They say they are rarely seen near the coastal communities of Ash River and Kabetogama.
Researchers suspect this means wolves enter those spaces at night to hunt and detect.
They also hypothesize that they approach humans because that’s where deer congregate, at least in part because so many other people feed them, especially in the winter.
“And we think the deer are almost congregating in the neighborhoods. ” And ultimately, predators pass by where the deer are,” Johnson-Bice said.
The researchers also note that they didn’t look at predation rates; They didn’t assess whether wolves were killing more fawns than they would otherwise. Instead, they looked at where wolves killed fawns.
They also noted that wolves disproportionately hunted and killed fawns in logged forest spaces over the past five years. These spaces provide forage for deer, as well as dense thickets of young plants that provide perfect hiding places for fawns.
Scientists have also found that wolves preferentially hunt fawns along “linear” features, forceline corridors, forest roads, and ATV trails. Researchers say this makes wolves more effective predators.
“Like humans, wolves prefer to move along linear corridors such as roads and trails rather than roam the dense forest,” said John Bruggink, a professor at Northern Michigan University and co-author of the study.
Through surveillance camera footage collected over several years, researchers also amassed evidence that wolves not only used roads and trails to move, but also served as hunting grounds, indicating that deer also used them as runners.
Gable said the effects of the allocation over the past decade, which now come with about two dozen papers published, are imaginable not only because of the advancement of technology, but also because of the length of the allocation and investment from the state’s Environment and Natural Resources Fund. Funds and other sources.
“I think over time we will be able to gather more knowledge about how humans are connected to those patterns and processes,” Gable said. “We hope to get to the bottom of this a little bit more. “