Is Habitat Restoration an Effective Way to Rebuild Low Deer Populations?|
By Tom Remington
I have written often of predator pits. A predator pit is created when deer populations have been reduced for various reasons and existing key predators, like coyote, bear and bobcat, can drive those numbers down further, perhaps prohibiting a regrowth of the herd. I believe that in areas of Maine, due to weather and other factors, deer numbers have been driven to very low levels. With multiple key predators that prey on deer, habitat conservation and restoration alone will not be effective in rebuilding the deer herd.
Predators on Maine's deer herd are somewhat unique in that deer are not their only prey species. Coyotes, for example, prey on many species and some believe this to be the reason coyotes will never extirpate the deer herd. In actuality, it may be for this reason they will.
It's called predator-mediated competition. If deer were the only prey species for coyotes, they may, under the right circumstances, eat up all the deer and move on, starve to death, resort to cannibalism or any combination thereof. Because there are more than one prey species, the coyote can survive heartily and remain in their habitat while continuing to drive the deer population even lower.
Dr. Charles Kay, Ph.D. Wildlife Ecology, Utah State University, writes in Muley Crazy Magazine, July/August 2010 issue, Vol 10 (4):21-25, of this exact situation and further states; “where this occurs habitat and habitat improvements are largely irrelevant, contrary to what most biologists would have you believe.” In other words studies exist that show that under the “predator pit” scenarios of predator-mediated competition, attempts to increase deer or other ungulate numbers not only failed but actually caused an increase in predation by cultivating predator-mediated competition.
A 10-year study, conducted by Mark Hebblewhite, University of Montana, College of Forestry and Conservation, Wildlife Biology Program, and others called, “Predator-Prey Management in the Nation Park Context: Lessons from a Transboundary Wolf, Elk, Moose and Caribou System”, shows much the same thing. The conclusions that could be drawn from this study shakes the foundation of knowledge of predator/prey relationships. This includes the notion that if wildlife managers and conservationists simply restore and/or improve habitat, it solves all the problems.
All attempts to improve habitat in this setting resulted in no improvement to ungulate numbers and as I pointed out, actually made matter worse.
Hubblewhite writes in his report: “Based on experiences in BNP, I show that wildlife managers face tough choices ahead and must come to terms with the truth that maintaining prewolf ungulate harvest regimes may be a fantasy in postwolf landscapes and, moreover, may be incompatible with ecosystem management.”
We mustn't conclude from this report that conservation of habitat isn't important as it absolutely is but there are lessons here in predator/prey management that have escaped too many conversations for too many years.
Predator management (control) has to be an integral part of any wildlife management plan. C. Gordon Hewitt wrote in 1921, “Any rational system of wild-life protection must take into account the control of the predatory species”. Maine, for various reasons, turned its back on predator control and as a result, two severe winters in a row exploited an already troubled deer herd. Maine now probably is facing the dreaded predator pit in parts of the state. Saving deer wintering areas only will not get the job done, but neither will providing a year-long hunting season on coyotes and making false claims about it. Had predators been in a reduced state, perhaps the deer losses would not have been as severe.
If Maine can get beyond the denial stages of the seriousness that may exist in regards to the deer, and if wildlife managers are still earnest about rebuilding the deer herd, consideration must be given to what has been discovered in more recent studies and the major obstacles that lie ahead.
Hebblewhite tells us that any hope of restoring ungulate herds, requires a minimum of a 70% reduction in wolf numbers until ungulates are restored and adjusted on an as needed basis.
Will Graves, author of “Wolves in Russia: Anxiety Through the Ages”, in an email to me said, “From my research I have learned that to help a particular prey species recover from a predation pit it is necessary to remove about 70 to 80% of primary predators (wolves in most cases) for at least three years.”
Maine already has areas where prime deer habitat isn't being utilized. There is a reason for that. We cannot put all the emphasis on habitat restoration in the belief it is the answer to rebuilding a deer herd in predator- dominated ecosystems. In those regions where the predator pit is in session, very serious predator reductions must be employed.
Tom Remington is co-owner of Skinny Moose Media, LLC, administrator of the Black Bear Blog and Executive Editor for several Online hunting magazines, including Maine Hunting Today. He is regularly published in several national newspapers and magazines.
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