Tickborne Disease Control Strategies Must Adjust to Reality, Researchers Say
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If your chewed-on hostas and decimated garden make you suspect that deer have put down roots in your yard instead of just passing through on the way to the woods, you might be right. New University of Maryland research debunks previous assumptions about how and where white-tailed deer live, and it has major implications for efforts to prevent deer overpopulation, and by extension, control the spread of disease-carrying ticks.
The five-year study conducted with the U.S. Department of Agriculture (USDA) found that deer in suburban environments often bed down and spend the night within 50 meters of residential properties. The study, published Monday in the journal Urban Ecosystems, is the first to detail hourly movements of white-tailed deer throughout different seasons.
“A big takeaway from this study is that neighborhoods are the home range of suburban white-tailed deer,” said Jennifer Mullinax, assistant professor in the UMD Department of Environmental Science and Technology and senior author of the study. “Agencies monitoring and estimating suburban deer populations may be missing a huge part of the population if they focus their monitoring efforts only on deer in wooded parks and undeveloped areas, because a lot of the deer are actually living in the neighborhoods, especially at night and in winter.”
The study results offer important guidance for suburban communities seeking to reduce the risk of tick-borne illnesses. An abundance of deer in residential areas serves as a reservoir for ticks, increasing their numbers and the risk of human exposure to diseases like Lyme disease and anaplasmosis. Reducing tick populations, by removing deer or treating areas where deer bed down, for instance, can help limit the spread of disease.
The study’s other authors include Patrick Roden-Reynolds M.S. ’20 and postdoctoral associate Cody Kent, both of the Department of Environmental Science and Technology, as well as Andrew Y. Li from the USDA Agricultural Research Service.
The researchers captured and collared 51 deer from five parks in Howard County, Md. The highly suburban study area included residential neighborhoods, schools, businesses and patches of open space or undeveloped land. The collars contained high-resolution GPS trackers that recorded deer locations every hour for 62 to 116 weeks.
The researchers found that deer tended to avoid residential areas during the day, but moved into residential areas nightly, especially in winter, often sleeping very near the edges of lawns and yards surrounding houses and apartment buildings. On average, 71 and 129 residential properties were found within female and male core ranges, respectively.
“We used to think people mostly got Lyme disease when they walked in the woods,” Mullinax said, “But recent studies have shown they’re getting Lyme disease in their own backyards, and now that we know the deer are living right there too, it makes more sense.”
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