VARIATION BETWEEN ECOSYSTEMS AFFECTS WOLF BEHAVIOR
A recent study on the predation of beavers by wolves by the Voyageur Wolf Project in Voyageurs National Park implies that the concept of a “trophic cascade” does not apply in their study area as cited in the Yellowstone wolf recovery. Voyageurs Wolf Project states the opposite case is found in VWP. To be fair, the VWP study is more general in nature but the principle point they make has to be rebutted. I will state my counter experience with the ramifications of wolves where I live in northern Minnesota.
Having known personally many Minnesota game wardens for years on a first name basis, many of whom have retired or passed away, I was privileged to hear many of their stories from their career. Most all of them cited how one the biggest parts of their job were protecting beaver from over trapping in the 30’s, 40’s and 50’s as beavers just barely hung on. For the past fifty years or more, beavers have flourished and every small pond has an intact beaver colony with a plethora of dams on creeks and streams. Paddling the backcountry streams and rivers, pulling canoes over beaver dams was commonplace and to be expected. Beaver pelt prices fell through the floor, fleece was introduced and trapping dramatically decreased.
I have owned a small wilderness “kettle” lake that has two large peat bogs on each end with poor fens found in the outer perimeter. The pond is considered a category 5 wetland due to its “open water” and “shallow fresh water ponds and lakes.” No dams were constructed here in order to make this pond. It was a result of the glaciers that covered the land ten thousand years ago. The entire “lake-drift” region is a plethora of these small ponds and lakes and the geology and soil types are vast in northcentral Minnesota. Whereas the far northeastern region comprising the Boundary Waters Canoe Area and Voyageurs National Park exposed rock and thin soils if any soils at all is known as the “Northern Superior Uplands.” In the large section comprised in the “Northern Minnesota Drift and Lake Plains” wherever you stand the soils are from 200 to 600 feet deep, which offers a richer and more diverse plant communities.
The large beaver lodge on my pond looks the same today as it looked over fifty years ago when I acquired this land. I believe its safe to suggest the lodge has been here for over a century. Over this period, I have visited this pond nearly on a daily basis and have never found evidence of beaver predation by wolves. About a mile from my pond is a grassy wetland that will have standing water in it. During wet years, beaver have constructed lodges and when the water levels drop during dry years, the beavers will burrow into banks. It is then that I have found where wolves have dug out the bank dens and eaten the beavers. This experience is widely seen in this region of heavier and deeper soils.
The only understandable conclusion to the difference in the variation between the two ecosystems is profound. The forests and plant communities found in the huge ‘drift-lake’ region compared with the much smaller and rocky soils of the far northeastern region of the state are entirely different ecosystems. Anyone spending time in Voyageurs Park, BWCA and the much larger Lake-Drift region is caught by the obvious differences, especially along shorelines. Aspens of different age structure dominate the forests and aspen, willow, alder and birch are prime beaver habitat in the MDL. Though these are all present in the NSU but they are nowhere as prolific as in the MDL.
Over the past fifty years I have logged close to 2500 miles in the BWCA/Quetico and love the land and the wilderness values that exist there but I have also spent countless hours tromping around the forests of NC and NW Minnesota. I have come to realize that wolves often hunt alone in the summer and hunt in packs in the winter. I have come across countless wolf kills, all deer, and if fresh enough, I will back track the wolf and deer tracks to see how the hunt unfolded but one of the most astonishing signs about the kills, is all the different inhabitants utilizing a wolf kill. For instance, one which has been similarly repeated is, snowshoeing through a densely thick white cedar/balsam swamp with my Springer when suddenly, without any warning, scores of ravens will spring into flight with their hoarse croaking. My first reaction is to call my dog back to my side as I immediately realize what I have come upon, a recent wolf kill. Most of these kill sites are less than 24 to 48 hours old as the huge array of wildlife that visit them are incredible in the alacrity and efficiency in cleaning them up. I have found ermine tracks, fisher, fox, bobcat, coyote, ravens and eagles. Visiting these sites, a week later the only evidence of what happened here is a few patches of deer hide.
There has always been a robust population of ravens but their numbers have greatly increased with the wolf recovery. I have counted as many as 8 bald eagles at and over these kill sites. The large presence of eagles here in the winter months are attributable to this ready winter food source along with road kills. Red and gray foxes have noticeably increased whereas their numbers were much lower before complete wolf recovery in this region. Coyotes were far more prevalent when wolf numbers were down. Coyotes are a rival to foxes whereas wolves generally leave foxes alone as they are not a rival. Magpies that were formerly an uncommon sighting are now common as they too capitalize on wolf kills. Even the relationship between wolves and ravens has become a mutualistic relationship as the raven is the wolf scout. In the summer months, turkey vultures flock to these kill sights. Porcupines, squirrels and small rodents chew on the bones for its calcium. Since the wolf population in MN has gone from 700 to over 2000 deer have also grown in herd size which is an indisputable fact!
It is my opinion that we know enough about wolves. Most wolf research seems to be searching for the negative aspects of wolves. We know about the pack structure and its social nature, we know wolves have territorial ranges, travel great distances, scent marking, mating, denning and rendezvous sites, disease, wolves are the best antidote to CWD, by limiting the deer population they keep over browsing by deer down. We need to embrace the wolf as he has made the land whole again. Too many researchers have bought into the game management model that if a species has rebounded, open a hunting season on them. Let us concentrate on the role what the wolf does to help the land, not some specific regional occurrence.
Ask Migizi (bald eagle) and Gaagaagiwag (ravens) what they think…. better yet just watch them, they will show that we are all related.
Barry lives off-grid in the Mississippi Headwaters Country of Northern Minnesota. He is a public lands and wolf advocate, local historian, author of the book Teachers in the Forest, and founder of the grassroots organization Jack Pine Coalition.