Deer and their impact

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Deer and their impact

Agricultural groups, ecologists and the state's commercial forest industry call on the Game Commission to reduce number of whitetails

Sunday, October 03, 1999

By Ben Moyer, Special to the Post-Gazette

Deer are on the minds of more people than just hunters as fall settles in over Pennsylvania. On Sept. 25, nearly 200 naturalists, farmers, municipal officials, professional biologists, ecologists, and hunters were in Harrisburg to discuss deer and their impacts on people and the landscape both share.

Mounting evidence suggests that abundant deer are damaging Pennsylvania’s forests. Ecologists are counting on hunters to help society solve the problem. (Post-Gazette)

Their forum was a conference titled, "The Impact of White-tailed Deer on the Biodiversity and Economy of Pennsylvania." (Biodiversity is a term used by biologists to describe the full range of plants and animals living in a particular region or ecosystem). Sponsors of the event included the Pennsylvania Audubon Society, Pennsylvania Chapter of the Sierra Club, University of Pittsburgh, Western Pennsylvania Conservancy and the Heinz Endowments' Western Pennsylvania Watershed Protection Program.

Conference organizers framed the problem this way: "There is growing agreement among wildlife biologists, land managers, ecologists, foresters and others that white-tailed deer have overpopulated much of their range, with profound, negative consequences for both humans and the other plants and animals that share the deer's world. Understanding those impacts is the first step toward correcting them, and finding a way to balance a healthy deer herd with the needs of people and the environment."

Until recent years, deer management was of interest to few people outside the ranks of hunters. In this state deer were most abundant in the extensive north-central forests where they seldom conflicted with human activities. Hunters who traveled north to hunt each fall enjoyed seeing large numbers of whitetails and considered high deer densities to be a normal and permanent feature of the region.

But in the 1980s and '90s, deer populations increased rapidly in agricultural and urban regions outside their traditional primary range. And as deer numbers grew, so did their impact on crops, suburban properties and highway safety. Simultaneously, scientists uncovered evidence that decades of heavy deer browsing in northern forests had stripped those lands of much of their natural wealth.

The most practical means of reducing the herds is to issue antlerless licenses in sufficient numbers to remove enough deer to allow vegetation to recover. The Game Commission achieved some success in reducing deer densities during the late '80s and early '90s. But, in general, major sportsmen's organizations have opposed increased antlerless tag quotas, and deer numbers are again on the rise wherever there is sufficient food to support them.

Organizers called the conference to focus attention on a problem that, according to one speaker, "has turned forest regeneration in Pennsylvania upside down."

Bill McShea, a forest ecologist with the Smithsonian Institution presented the results of research he conducted on the influence of deer on the diversity of woodland birds. McShea built exclosures (wire fences to keep deer out) in Shenandoah National Park, then studied the response of vegetation to reduced deer browsing, and monitored the number and variety of bird species nesting there. He documented higher nesting success for woodland birds such as hooded warblers, American redstarts and wood thrushes inside the exclosures where deer could not browse the forest's shrub understory.

"It's an indirect effect on birds," McShea said. "The deer are after the vegetation. As they thin the shrub layer, nest sites for birds become harder to find and any nests birds do build are easily spotted by predators. They have no visual defense against snakes, raccoons, hawks, cats or any predator that's out there. The result is that these species decline across entire landscapes heavily browsed by deer."

Botanist Ann Rhoads of the Morris Arboretum in southeastern Pennsylvania has studied the influence of deer on native plants across the state. "We've lost whole communities of herbaceous plants," Rhoads noted. "We're accustomed to noticing deer damage by the existence of a browse line from 1.5 to 2 meters high, the limit of where deer can reach woody browse. But by the time a browse line becomes established deer have already destroyed much of the herbaceous plant community on the forest floor."

Rhoads noted that the losses included familiar wildflowers like trillium, bloodroot and starflower, pointing out the example of Trillium Trail in suburban Pittsburgh where deer grazing has destroyed the annual blooming spectacle of white trillium. She explained that across thousands of acres in northern Pennsylvania, native wildflowers have been replaced by an unbroken sea of hay-scented fern, which deer rarely eat.

"It will take an active and expensive effort if we are ever to rejuvenate these forests," Rhoads said. "Deer have altered them so significantly that they will not return to their natural state in our lifetimes. But we're at a position to head off the damage, and the need for expensive restoration in many parts of the state, if we manage deer responsibly now."

Susan Stout, a researcher at the U.S. Forest Service Forestry Sciences Laboratory in Warren, said the state's commercial forest products industry loses $75 million annually to deer. "Fencing to allow new trees to grow out of the reach of deer costs about $150 to $200 per acre," Stout said. "And expensive maintenance is needed after every single wind event that brings branches and trees down across the fence."

Stout showed color slides of forestry workers sheathing tree seedlings in plastic pipe to protect them from browsing deer. Citing research conducted on the Heart's Content Scenic Area in the Allegheny National Forest, Stout reported that the number of plant species on study plots there has declined from 41 to eight.

"It appears that no new trees grew out of the reach of deer at Heart's Content between 1929 and 1989," Stout said.

Lebanon County Farmer and Pennsylvania Farm Bureau representative, George Wolfe said farm losses to deer were about equal to that felt by forestry, approximately $70 million.

All speakers and most attendees agreed that hunting was a key to the problem's solution, and that if Pennsylvania is to have any hope of maintaining its natural wealth, the future of hunting must be nurtured and sustained.

"We tried a whole range of non-lethal control practices," said Dan Townsend, Director of the Lacawac Sanctuary in Monroe County. "We tried repellents, fencing, trap-and-transfer, we even explored the possibility of using immuno-contraceptives to cut down the population. Hunting appears to be the only practical approach on a landscape level."

"Hunters, naturalists, conservationists and everyone concerned with Pennsylvania's natural environment can come together on this issue," said Cindy Dunn, executive director of the Pennsylvania Audubon Society. "For some reason those who enjoy wildflowers and songbirds are sometimes viewed as being at odds with the hunting public, but we need to support one another for the good of the wild heritage we all value."

The challenge is for hunters to accept policies that reduce deer numbers to levels that allow other species, farming and commercial forestry to co-exist with a herd in balance with its surroundings.

Steve Trupe, a hunter and member of the Pennsylvania Deer Association addressed the gathering on behalf of the state's one million licensed hunters.

"There are a whole range of attitudes among hunters toward this problem," Trupe said.

"A minority will never accept fewer deer, but most, I think, are willing to be shown the problem and to work together to solve it. But I don't think you can force the idea of biodiversity too quickly. I think the answer lies in finding appropriate places around the state to accommodate the values of everyone. Some places could be allowed to hold higher deer numbers, while others could be managed to protect biodiversity. It will take discussion and fair consideration of all sides."

In practical terms, the Game Commission's efforts to fine-tune deer management are hampered by the lack of any means of distributing hunting pressure where it is needed. Spokesmen for sportsmen's groups say the current approach of issuing antlerless tags to county management units promotes over-harvest on public lands without addressing the problem of abundant deer on posted private lands that sometimes serve as deer shelters.

In the view of Scott Williamson, a field representative for the Wildlife Management Institute, those who organized and attended the conference have made an important first step toward progress.

"This conference illustrates the diversity of people today that have concerns about deer," Williamson said. "[Wildlife Management Institute works] in all 50 states, and we see more examples every day where very complex wildlife management issues are resolved only when you bring all of the stakeholders to the table, and not just focus on one user group. Pulling together all the different viewpoints makes the process harder and more contentious, but it also makes the benefits more permanent."