Deer, Lyme disease explored



BAR HARBOR — Significantly reducing the deer population would be an effective way to reduce deer ticks and Lyme disease exposure to humans, a member of the Maine Medical Center’s Vector Borne Disease Lab told a standing-room-only crowd in council chambers Monday evening.

However, the deer management proposal voters will face on the ballot next week would likely fall short of that goal because so much land in Bar Harbor and Mount Desert Island would remain closed to hunting, he said.

Reducing deer numbers to less than 20 per square mile would have a major effect on the deer tick population, field biologist Chuck Lubelczyk said. The reproductive cycle of deer ticks would be directly interrupted by such an action. A cull of that extent would be a very effective way of cutting Lyme exposure, according to Lubelczyk.

While state and Acadia National Park wildlife biologists do not have a recent deer census to go by, all agree that the current population is far above the 20-per-square-mile mark. Bringing it down to that level does not seem to be the goal of the proposed management plan. With Acadia controlling half the land mass in Bar Harbor, deer would have a vast refuge in any hunt situation, and, “That’s the problem,” Lubelczyk said.

“The deer aren’t stupid. They know when some kind of pressure’s on them in one area, and they go to another,” he said.

State wildlife biologist Tom Schaffer, who has worked with the deer herd management task force to develop the proposed plan, said following the meeting that the proposal is as good as it can be at this time. While deer population numbers would likely not go down overall, areas where hunting was allowed could see a large reduction in the number of the animals.

“After three or four years, the average may not change a whole lot, but there is a high likelihood that it can affect areas outside of the park and reduce the opportunity for ticks to reproduce,” Schaffer said. “We’re affecting change where change can be affected, and that’s the best we’ve got.”

The task force has based its management recommendations on the idea that deer have exceeded their social carrying capacity in Bar Harbor, meaning that the number of deer/car accidents, damaged gardens and Lyme disease cases are higher than people want them to be. Monday’s meeting was set up by the task force to provide information on the connection between deer, deer ticks and Lyme disease.

Opponents of the plan packed the room for the meeting. Several cited studies contradicting Lubelczyk. He responded in an educated manner to each. Some opponents took their argument past science and insisted that Lubelczyk was only brought to further the idea that deer should be killed.

“You are one scientist brought here by the deer task force to represent one point of view,” Joan Tukey said.

“The deer task force has an agenda. They want to wipe out our whitetail deer, and that’s their agenda,” Janie Whitney said.

Bar Harbor has the distinction of being the first place in Maine where a deer tick was found, in the early 1980s, Lubelczyk said. It is now among the “hottest” areas in the state for ticks, with numbers as high as those in Southern Maine. Lyme disease cases have grown exponentially in the state over the past two decades, reaching an estimated 13,000 annually.

Deer ticks thrive in areas of broadleaf forest, he said. The fire of 1947 on MDI led to large swaths of such forest here, creating “the perfect habitat for ticks,” Lubelczyk said.

Deer ticks hatch in the spring and early summer, and take their first meal from squirrels, mice and other small rodents, or ground foraging birds. It is from these animals that they acquire Lyme disease. The tick hibernates until the next year, when it eventually seeks a blood meal from a large mammal, specifically from deer most of the time, Lubelczyk said. After this meal, the tick falls to the ground and gives birth the following spring.

While other large mammals might carry several deer ticks, deer will carry up to 100 at a time. When these ticks are fully engorged, they can hold up to 1,000 eggs, giving a single deer the potential to aid in the creation of 100,000 new ticks.

“Deer are the sole critical wild host for reproduction,” Lubelczyk said. “Without the whitetail deer, the ticks don’t get their last meal, so they can’t lay their eggs.”

Several management opponents at the meeting came ready to argue that recent news articles about research shows that reducing deer does not affect Lyme disease. Lubelczyk said that those headlines are misleading. The studies basically show that limited reduction does not work, but in no way do the studies disprove the idea that significant reduction would work, he said.

Lubelczyk said that he considers deer management to be one tool of several that can and should be used to combat Lyme disease. Other tools include personal protection measures, pet protection measures and actions taken on one’s own properties to reduce undergrowth habitat and rodent populations.

While significantly reducing the deer population is not realistic in Bar Harbor under current circumstances, when combined with other methods of Lyme protection, even a limited hunt would help contribute to reduced exposure, he said.

“Deer reduction is a tool, one way or another. I know to some extent that it does work if it’s used correctly,” Lubelczyk said. “You have to look at Lyme disease and tick management as a toolbox. You should not exclude or embrace one method solely over others, and you’d be crazy not to take advantage of every tool.”

 

Robert Levin

Robert Levin

Former reporter Robert Levin covered the people, businesses, governmental and nonprofit agencies of Bar Harbor. [email protected]
Robert Levin

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