Regulated deer hunts in Indiana state parks have helped restore forests that were damaged over the years due to a rise in white-tailed deer populations, a Purdue University study shows.

The research team found that a 17-year-long policy allowing organized hunts in the state parks, exercised by the Indiana Department of Natural Resources (DNR), successfully spurred the regrowth of native seedlings, herbs and wildflowers picked off by hungry browsing deer.

And though hunting may be viewed as an unpopular and possibly unkind solution to these nibbling deer, it is an effective means of promoting the growth and richness of Indiana's natural areas.

"We can't put nature in a glass dome and think it's going to regulate itself," study leader Michael Jenkins, associate professor of ecology at Purdue, said in a statement. "Because our actions have made the natural world the way it is, we have an obligation to practice stewardship to maintain ecological balance."

Hunting used to be banned in Indiana's state parks, until the 1990s when white-tailed deer populations swelled, leading to the disappearance of many native wildflower species such as trillium and lilies, replaced by wild ginger and exotic species such as garlic mustard and Japanese stiltgrass - plants not favored by deer.

To keep these overabundant deer populations in check, the DNR introduced controlled hunts in state parks in 1993, with most parks adopting 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."

To test their effectiveness, Jenkins and his colleagues compared the amount of plant cover in 108 plots in state parks and historically hunted areas with 1996-97 levels. The number of plants more than doubled between then and 2010. The number of herbs increased from 20 to 32 percent and grass cover increased from one to three percent. Tree seedlings also jumped from two to 13 percent, 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," co-author Lindsay Jenkins (no relation) 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."

The study was published in the journal Biological Conservation.