Which animal are you afraid of most? Mountain lions, bears and bobcats have all been sighted around the forests of Pennsylvania, and mosquitos kill more humans annually around the world than any other. The deadliest animal in our state, though, seems to be a gentle giant: the white-tailed deer.
Directly responsible for 4,857 car crashes and 21 fatalities in 2023, the animal presents a huge problem for local drivers. Indirectly, deer are responsible for spreading ticks that cause Lyme disease, possibly infecting over a million Pennsylvanians.
Due to dozens of extenuating factors, the sky-high deer population is out of equilibrium with the local environment. The herbivores pick understories clean, removing brush, saplings, bushes and small plants from forests around the area.
A Management Plan
Thus conservation organization Natural Lands has stepped in with a new management solution at Hildacy Preserve in Media this fall. Instead of building an enclosure or pen to keep deer in and moderate large swaths of land, they’ve built an exclosure at the preserve to keep the animals out. Measuring 800 linear feet, its eight-foot-high fences are too tall for deer to comfortably leap and keep the forest inside growing naturally.
“The concept is to fill this exclosure area with native plants—canopy and understory trees as well as shrubs—to replicate what would occur naturally at Hildacy Preserve were it not for the extreme deer pressure,” says preserve manager Mike Coll. “I’ll be planting in dense groupings inside the fence with a diverse mix of species. As these plants mature, they’ll provide food, shelter and breeding habitat for insects, songbirds and other wildlife.”
This revised setup is doubly beneficial for the region. Not only will it provide safety for young forest plants, but it will also improve local water quality in Crum Creek. Native plants in the floodplain soil and added tree cover will prevent runoff into waterways. Furthermore, the shade from the trees will lower stream temperature. Leaves from native plants falling into the water will be decomposed by macroinvertebrates that live in and near streams specialized to specifically eat only native growth.
“So, by having a greater amount of native plants, you’re shading the creek, you’re slowing the flow and you’re introducing food into it for the things that live in the creek. And those little creatures are the ones that are ultimately breaking down everything that’s going through the creek, reducing sedimentation and contributing to overall stream water health,” says Coll. “That stream from the creek flows further down and ends up at a drinking water plant.”
Natural Lands hopes that this exclosure is the first of many to appear at its preserves. Though funding may be a limiting factor, this smaller exclosure cost approximately $18,000, more than half of which was donated in a grant from the Aqua Essential and Pennsylvania Environmental Council.
Past to Present
Ideally, one day exclosures will no longer be necessary. Prior to European colonization, white-tailed deer were in balance with the environment, but after nearly being hunted to extinction, the PA Game Commission began importing deer from the Upper Peninsula of Michigan. Because a large portion of the large predators—mountain lions, bears and wolves—had left the area, these new deer multiplied boundlessly to a population of about 1.5 million, or approximately 32 deer per square mile, which is three to four times the region’s carrying capacity.
“To the casual observer, the woods still look green, but they are much altered,” notes Roger Latham, Ph.D., an ecologist and conservation biologist with Continental Conservation and a former member of Natural Lands’ board of trustees. “In place of the diverse, multi-storied vegetation that was the norm, there are just a few species, either not preferred by deer or resilient to repeated browsing.”
The local deer population is diminished regularly by hunters supported by Natural Lands and organizations like them, but such hunters are unable to discharge firearms within 100 yards of a residence, making culling impossible in much of the state. Even if that rule didn’t exist, game hunting doesn’t take down enough deer to bring the population down to pre-colonial levels.
The Question of Market Hunting
Though the PA Game Commission does promote regular culling by using trained hunters from elevated locations, Latham advocates restoring market hunting.
It’s a wildly unpopular sentiment, especially given that nearly drove the local deer population to extinction during the 19th century. And since the 1890s, selling wild deer meat has been illegal in Pennsylvania and much of the United States. When you order venison in a restaurant, it’s often imported from farms in New Zealand, despite the 1.5 million deer in our backyard.
“[Market hunting] became a taboo, and it became really ingrained in the culture. So there’s still a huge taboo among people who grew up hunting, and they got it from their father and their father got it from the grandfather and the grandfather got it from the great-grandfather right back to 1890 when the game commission first went into business,” Latham notes. “Hunters think that if there’s market hunting, they will never be able to hunt again because there won’t be any deer.”
Latham doesn’t believe market hunting is coming to Pennsylvania any time soon. While building exclosures is a more passive way of regulating environments, market hunting would confront the problem at its source, through it is a more extreme solution.
It’s ironic, right? Market hunting destroyed the local deer population in the 19th century, but now it seems this solution could help rebalance our ecosystem. Whether local organizations stick to exclosures and hunting for sport or one day return to market hunting, the environment will be impacted just as it was over a century ago. For now, the exclosure at Hildacy Preserve seems to be a step in the right direction.
Related: This Exton Development Includes a $2.4 Million Floodplain Restoration
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