Wolf recovery vs. ecosystem health

Gray wolf, Canis lupus. (AP Photo/U.S. Fish and Wildlife Service, J. & K. Hollingsworth)

The idea may be exotic to many wolf conservation advocates, but a group of researchers are floating a proposal to introduce very small groups of wolves to small pieces of habitat as a management tool. The goal has little, if nothing, to do with wolf recovery and everything to do with managing ecosystem health and services. It’s an inversion of the logic that is often used to support wolf recovery. Many wolf advocates (myself included) have touted the ecological benefits of wolves as a weighty “pro” to their reintroduction. The story of trophic cascades in Yellowstone National Park and the Lamar River Valley as a direct result of gray wolf
reintroduction is one that I feel like I’ve heard ad nauseum for the past five years, and it’s still going strong. Wolf-mediated trophic cascades was the subject of the keynote talk at the Defenders of Wildlife Carnivore Conservation in a Changing World conference in Denver, Colo. last fall, and wolf-mediated trophic cascades were a large focus of the cover story “Wolf Wars” in National Geographic this month. But a new study published in the March issue of BioScience, “Using Small Populations Of Wolves for Ecosystem Restoration and Stewardship” {1} flips this on its head and essentially says, “We’re not proposing this idea as a wolf recovery tool; we’re proposing this as an ecosystem management tool.”

Elk grazing in the Klamath National Forest. This image was meant to show positive effects of prescribed burns, but I'm using it to highlight browing/grazing interactions with plant communities. (Forest Service image.)

Lead author Daniel Licht is a National Park Service employee in Rapid City, South Dakota and he and his team point out that smaller pieces of land have traditionally been overlooked for reintroducing wolves due to size constraints alone, but small publicly-held tracts often have the same need for ecosystem restoration as the larger tracts that are ultimately chosen for wolf programs. By removing wolf recovery as a goal, he and his team propose using single packs of wolves to re-balance overgrazing by herbivores and restore the “ecology of fear” {2} to systems where vegetative communities in particular need continual management for grazing and browsing mammals. The “ecology of fear” is a nifty concept coined by Ripple and Beschta (2004) that explains a behavioral change in the grazing habits of elk as an anti-predator response. When wolves are present, elk are documented to stay more often in protected forested areas and avoid open grassy areas and unprotected riparian habitat. This avoidance allows for young trees to get past the stage of being tasty young shoots and grow into sapplings and trees. The presence of a single pack of wolves in these smaller areas could help to balance the herbivore population and give the plant communities a break, the thinking goes.

But you simply can’t let a handful of wolves go in a National Park without some form of management plan in place for them, so the paper proposed two main categories of control: geographic control and reproductive control.

Let’s start with geographic control. Because their main idea is to restore ecosystems within publicly-held National Parks or other lands, and because these are geographically bounded, it follows that they propose mechanisms to keep the wolves within the geographic boundaries. This has been a major source of contention within the Mexican Wolf Reintroduction Program, which requires wolves to stay within a politically-defined area, and it’s been a source of consternation for opponents to the Northern Rocky Mountain Wolf Recovery program, because ranchers and local citizens dislike the free-ranging aspect of the program. Now, it’s important to recognize that wolves are biological dispersers. It’s encoded in their genes to roam, to find new territory and new mates. So keeping them constrained is, in a way, fighting their biology. The authors propose a variety of methods from physical fencing, to GPS-collars coupled with cell phone technology that sends a text message to managers when wolves are near (or have crossed) a virtual barrier. They argue for physical fencing in agrarian areas, where the risk of social opposition is highest.

Perhaps least palatable to wildlife advocates is using shock collars to achieve geographic control of wolves. These work similar to the shock collars used on yard dogs, and I’ve previously written a post about a study testing shock collars on gray wolves {3}which showed successful avoidance of specific areas when shock collars were worn, but less avoidance when the collars were removed. I predict it will be quite difficult to garner support for Licht’s idea from the wolf-conservation advocates if shock collars are on the table. It’s just a non-starter for a lot of advocates, and cuts against the grain of people’s idea of wolves as symbols of wilderness. In fact, I bet a lot of groups would align themselves and sue over this measure if it were enacted, regardless as to whether wolf recovery was a goal in the project or not. Getting past the animal activists would just be plain tough on this issue.

If fences are ho-hum, the idea that seemed the most whizbang to me was using bio-markers. It just makes sense. A carnivore’s world is largely ordered by scent, and packs spend a lot of time marking their territory with urine, well-placed scat and anal gland secretions. So why not use this to create a phantom pack or two that would largely keep the ecosystem-worker-wolves in place? There is a possibility that both auditory cues, like howling, and scent marking work synergistically to demarcate a pack’s territory; in which case, the author’s acknowledge that bio-marking would need to include both scent marking and auditory cues. I’d love to see some experimental research on this idea!

Reproductive control is nearly as controversial as the shock collars. The paper’s authors state that to manage the small populations of wolves, “Immunocontraceptives, pharmaceuticals, and surgery could all be used to prevent or suppress growth of a small population of wolves that is reintroduced for purposes of ecosystem stewardship…” This is an area I know considerably less about. Whether its chemical sterilization or surgical sterilization, I’d need to do a lot more reading to weigh the evidence before forming an opinion of my own. However, I think the opponents to wolves would be slightly assuaged by the option of having non-breeding individuals present while wolf supporters would probably be non-plussed. Many advocates love the idea of wolf pups almost as much as opponents abhor them. And I’d also want to do some reading as to whether the behavior of a pack would change if they were unable to breed. Because the whole point of using them as ecosystem managers would be to mimic their natural social and ecological roles.

Overall, I think this is an intriguing idea. But I think it would be difficult to get the current wolf advocacy crowd completely behind this concept because it takes away some of the things this group loves to fight for. At the same time, it offers the wolf conservation detractors placating features that would perhaps elicit greater tolerance from this group for wolves’ presence on the landscape. Maybe this sort of middle road is what our continent needs. After all, a whole landscape-level ecological shift has occurred in the intervening years since eastern and western wolves were extirpated from the United States, and increasing numbers of mesopredators abound in some areas. These smaller carnivores don’t have the same ecological role as do wolves {4}, and so using small populations of wolves could take a few steps toward mitigating this ecological shift toward restoration.

The biggest problem, as always, will be overcoming the prejudices and fears in people’s minds — on both the wolf conservation and wolf opponent sides of the fence.

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NOTES and SOURCES:

I originally wrote this post on March 10, 2010; but in switching over to using ResearchBlogging.org I needed to re-post it for the system to recognize it.  Thanks for your patience.

{1} Licht, D., Millspaugh, J., Kunkel, K., Kochanny, C., & Peterson, R. (2010). Using Small Populations of Wolves for Ecosystem Restoration and Stewardship BioScience, 60 (2), 147-153 DOI: 10.1525/bio.2010.60.2.9
{2} Ripple, W.J., and R.L. Beschta. 2004. Wolves and the Ecology of Fear: Can Predation Risk Structure Ecosystems? BioScience. (54)8: 755–766.
{3} Hawley et al. 2009. Assessment of Shock Collars as Nonlethal Management for Wolves in Wisconsin. Journal of Wildlife Management. 73(4): 518–525
{4} Prugh, et al. 2009. The Rise of the Mesopredator. BioScience. 59(9): 779-791.

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