The Bambi effect: Are deer a bigger threat to NC forests than climate change?
There's no arguing they've made a remarkable rebound after being nearly hunted to near extinction in the late 20th century in many places, including North Carolina.
But have white-tailed deer been too successful in bouncing back from the brink after centuries of unregulated hunting? Of equal importance, are they now a threat to the very environment − even more than climate change, some scientists argue − that regulators and biologists have worked so hard to protect to help them recover?
"We've eliminated the controls on them," said Dr. Doug Tallamy, an entomologist and wildlife ecologist at the University of Delaware, referring to the eradication of top predators like mountain lions and wolves, "and we've created the perfect edge habitats for them.
"There's nothing good, for us or the environment, with the current situation."
That has some researchers mulling changes in how we approach deer management, adaptations that would require intense public debate and generate plenty of controversy but would offer forests of the future a fighting chance as they struggle to adapt to changes brought on by climate change.
'Imbalance in the ecosystem'
The impacts of North Carolina's more than 1.1 million deer on the environment − and people's lives − aren't hard to see.
Suburban home gardens are often viewed as easy, tasty buffets by deer, and driving during dusk or dawn can be a nervy ride in many parts of North Carolina.
According to the N.C. Department of Transportation, the top 10 counties in the state had a combined 16,597 animal crashes − the vast majority involving deer − from 2019 to 2021. Those crashes caused nearly $49 million in damage, 751 injuries and six deaths. Locally, Brunswick County came in at No. 10 with 1,331 crashes.
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Deer also carry ticks that can pass on Lyme disease to humans, and an over-abundance of animals can help spread chronic-wasting disease, a fatal neurological illness, among herds.
But it is the deer's voracious appetite that has scientists especially concerned.
Dr. Jim Gregory, a retired forester with N.C. State University and a member of the Alliance for Cape Fear Trees, said in areas where deer numbers are above the carrying capacity recommended by biologists it isn't hard to see the damage from the "browse line" down − literally the height deer can reach to feed.
"The entire groundcover and understory is devastated," he said. "That process has caused an imbalance in the ecosystem because that understory is an important habitat for so many other organisms."
According to biologists, deer eat up to 5% of their body weight every day.
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As gardeners know, deer love practically anything that flowers. In forests, they also enjoy munching on fresh shoots of greenery during the spring and acorns to sustain them during the colder months. That's led to added pressure on oak trees in some areas, limiting diversity and slowing the replacement of trees lost to storms or development and opening the way for their place to be taken by faster growing, less environmentally useful plants or even invasive species.
'No more safe havens'
What has scientists especially concerned is how the overpopulation of deer could make the environmental changes tied to climate change even more damaging.
Take for example a tree or plant that needs a period of cold weather to survive and thrive. If the vegetation was an animal, it would simply move to a climate it was more comfortable in as global warming pushes up temperatures in its usual native range. According to the National Oceanic and Atmospheric Administration (NOAA), temperatures in North Carolina have risen by more than 1 degree since 1900, with increased warming − likely happening more quickly − forecast for this century.
Plants are trying to do that, albeit at a much slower pace than animals.
"But because of the sheer number of deer in many places, there are no more safe havens," said Dr. Bernd Blossey, a professor of natural resources and the environment at Cornell University.
He added that plants also might not be able to have time to evolve, like some animals have in response to their changing environment, because they will be eaten before they have the time or can pass on the genetic changes to future generations.
"There are forces in nature than can help plants deal with climate change, to help them adapt," Blossey said. "There is power in there. Nature isn't weak. But if we have deer in that natural system, that simply doesn't allow that to happen."
Which brings us back to how best to control deer populations.
Researchers say there really is only on option − although some communities, like Bald Head Island in Brunswick County, have tried putting their deer herd on birth control. While some of those initiatives have shown promise, reducing animal density and allowing over browsed areas to recover, such programs are expensive and only really work if you can prevent new animals from joining the herd.
"We know how to control them," Tallamy said. "You either bring back the predators, or you hunt them. And since it's unlikely the public is going to allow the widespread reintroduction of wolves or cougars, that leaves us with hunting."
Many communities around the country have implemented controlled hunts with expert marksmen, often law enforcement or former military personnel, to help thin their herds. States, including North Carolina, also are trying to entice more people to start hunting − a push that showed promise during the pandemic when many other recreational opportunities were closed or severely limited.
But both Tallamy and Blossey said what they think would really work isn't simply more people taking part in recreational hunting during specific windows of the year like we have now, but a whole new approach to hunting.
"It's going to have to be market hunting," Tallamy said, noting that deer numbers in some Eastern states are more than 14 times over the carrying capacity of local ecosystems to sustain them.
Market hunting, in theory, would allow hunters to hunt deer all year long and then sell their venison to the public − something that isn't allowed today by federal law.
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Blossey said research has shown that hunters, in general, aren't interested in taking more deer after they reach their legal limit, which is set by states and differs by weapon type and the sex of the deer. So incentivizing hunters to take more animals, such as allowing them to profit off them, would be required to put a real dent in deer populations. Such a change also would require regulatory agencies to change how they view management of deer herds, something that's generally been done to provide adequate animals for hunters, who pay fees to help support wildlife agencies.
According to the N.C. Wildlife Resources Commission, state hunters harvested nearly 168,500 deer in 2021-22. Locally, the deer takes were 158 in New Hanover County, 2,450 in Pender County, and 1,582 in Brunswick County.
The agency also said that the state's deer population of roughly 1.1 million has held pretty steady since the 1990s.
The Bambi effect
But widespread hunting, likely with guns in rural areas and sharpshooters or using bows or crossbows in more developed areas, would require some deep shifts in societal attitudes.
“The Bambi effect is real, especially when you are young," Tallamy said. "No one wants to be the predator, but that's where we are now."
Blossey echoed the sentiment.
"People in general don't lean toward taking active interference in managing something like this, saying let's just let nature take its course," he said. "But we've already altered nature.
"This is the nature we've created."
Reporter Gareth McGrath can be reached at GMcGrath@Gannett.com or @GarethMcGrathSN on Twitter. This story was produced with financial support from 1Earth Fund and the Prentice Foundation. The USA TODAY Network maintains full editorial control of the work.
This article originally appeared on Wilmington StarNews: Are deer a bigger threat to NC forests than climate change?