RVCC Biologist: Deer Population Threatens New Jersey’s Forests, Wildlife
New Jersey’s forests are in a “crisis” because of the ever-expanding deer population, a Raritan Valley Community College professor told an audience in the Township Council chamber on May 21.
Jay Kelly, an associate professor of biology at RVCC, told the several dozen people assembled for the Environmental Commission’s deer and invasive species seminar that if nothing is done to reduce the overall deer herd in the state, forests and other wildlife will disappear.
Kelly offered several remedies, ranging from contraception to fencing to hunting. Of all of the proposed remedies, Kelly said, hunting was the most cost-efficient and effective.
“We have this crisis where our forests are really heavily degraded, they’re not supporting our wildlife like they’re supposed to or like we would want them to, the trees are not able to reproduce and eventually they’re going to disappear, so something has to be done,” he said.
“If the deer population remains what it is for the next 50 years or so, we’re going to start seeing declines in the trees within our forests as a whole,” he said. “I’m really cautious about making statements, I really don’t want to sound like I’m exaggerating or overstating something. I can’t see any other way that that wouldn’t be possible if this trend continues.”
“You can see it right now as you drive down the highway and see small forest patches, and when the trees die and fall down, in that gap that’s created it’s just a tangle of weeds and bushes, there’s no young trees growing up to replace them,” Kelly said. “So this thing has actually started in the real world. It’s really kind of frightening if you want to keep our forests alive.”
He said studies have shown that the a healthy ecosystem can only support about 10 deer per square mile. He said that when the density of deer moves above that, “we start to see certain plant species begin to disappear from the forest. The things that the deer like to eat the most, Trillium and lilies, many of your plantings in your yard, they start to disappear.”
“When you get to 20 deer per square mile or more, you start to see forest regeneration as a whole shutting down,” he said. “So the trees that are trying to reproduce, the vegetation that is on the floor and other things that are there also begin to disappear.”
He said studies have shown that the deer density in this area is about 76 deer per square mile, going as high as 100 per square mile in certain areas.
“If 10 per square mile is good for a healthy ecosystem, you can imagine what 70 or 80 is going to mean for whatever’s trying to survive,” he said.
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Kelly said the deer foraging for food in the forests lead to a domino effect on other species.
Trees can’t regenerate because the deer are eating the saplings, Kelly said. The vegetation being eaten by the deer are also favored by certain insects, which won’t eat anything else and will begin to die off. The same fate awaits birds for which those insects are the main form of sustenance, he said.
“These effects of deer on the landscape aren’t just impacting our gardens and they aren’t just impacting the plants in the forest, it’s affecting the wildlife as well, so you can kiss your butterflies goodbye, kiss the forest birds goodbye,” he said. “It just cascades through the ecosystem in this waterfall of downstream effects. It’s really a crisis in terms of what it’s doing to our wildlife.”
The overabundance of deer also pose public health and safety problems, Kelly said.
Deer are the primary mode of travel for Lyme Disease-bearing ticks, he said. There are also about 30,000 deer-car collision in New Jersey every year, which leads to an estimated $100 million in automobile damage claims, he said.
Towns and counties are struggling to deal with the deer population, Kelly said.
While other methods of control have been tried, he said the most effective is some sort of hunting program.
The programs can take the form of recreational hunting, professional sharpshooters or “management hunting” with small groups of experienced hunters.
Other methods, such as planting new trees, erecting 8-foot-tall fences to keep deer within a certain area and contraception are too expensive and not very effective.
Contraception, Kelly said, works best in small, confined areas. To try it in the open landscape, he said, “is just not feasible.”
Still, he said, “it’s certainly something that should be considered.”
Invasive species of plants and vegetation aren’t helping matters, Kelly said. In fact, some of them are killing trees, while others are being ignored by deer and insects because they’re not recognized as food.
About 400 of the 4,000 species of vegetation that grows in New Jersey is invasive, he said.
“Invasive species grow in the wild in an uncontrolled way and wreak havoc,” Kelly said.
“In the same way that deer are depriving insects of the food that they need and depriving birds of the food that they need, these invasive species don’t do very much to support our wildlife,” he said. “It’s a food desert for the insects that refuse to eat them.”