Controlled Deer Hunts Helped Restore Forests in Indiana State Parks

A new Purdue study shows how controlled deer hunts in Indiana State parks helped restore the forests that were damaged due to the rise in white-tailed deer population.

The study led by Michael Jenkins, associate Professor of forest ecology, found that a 17-year-long Indiana Department of Natural Resources Policy of organizing hunts in state parks had been successful in spurring the re-growth of native tree seedlings, herbs and wildflowers that had dramatically reduced due to the increase in deer population. Though hunting is unpopular, it is an effective technique of encouraging growth of Indiana's natural areas.

"We can't put nature in a glass dome and think it's going to regulate itself," he said. "Because our actions have made the natural world the way it is, we have an obligation to practice stewardship to maintain ecological balance."

Hunting was banned at the Indiana State Parks, but since the 1990s there was a sudden rise in the white-tailed deer population due to which several species of native wildflowers like lilies and trillium gradually vanished and were replaced by wild ginger and exotic species like garlic mustard and Japanese stiltgrass as these plants were not favored by the deer. Oak and ash tree were replaced with pawpaw since it is deer-resistant. Due to lack of food resource, the health of deer in the state parks dwindled.

In order to check the rise in deer population, the researchers introduced controlled hunts in the state parks in 1993; however, most adopted the strategy by 1996.

"Hunting in natural areas is controversial," Jenkins said. "But when deer are overabundant, they start to have undeniable negative impacts on the ecosystem."

The effectiveness of controlled hunting was tested by comparing the amount of plant cover in 108 plots in state parks and the hunted areas with 1996-97 to 2010. The number of herbs increased from 20 to 32 percent and grass cover increased from 1 to 3 percent. Tree seedlings jumped from 2 to 13 precent, suggesting that when older tees die, they are replaced by younger trees.

"We saw a striking improvement in the quality and diversity of the forest understory in state parks compared with conditions before the hunting program," Lindsay Jenkins said. "The deer management program is having a clear, beneficial impact on Indiana parks and could serve as a good example for nature preserves with overabundant deer in other states."