Based on the research of Dr. Rick Ostfeld and colleagues
How many acorns do you see along the trails? If you see a lot, you may be witnessing an acorn mast. This is when oak trees produce more acorns than usual—a feast for the animals that eat them, such as mice, chipmunks, and deer.
Abundant acorns mean that more animals will survive the winter to reproduce. Following a mast year, more than 300 mice were found on one 5.5-acre forest plot. This is where the blacklegged tick (also called the “deer tick”) comes in.
What to know about ticks
Ticks have four life stages: egg, larva, nymph, and adult. During each of the last three stages, ticks need to eat a blood meal. Larval and nymphal ticks live on the forest floor. When there are lots of mice living among them, acquiring a blood meal is easy, and more ticks make it to adulthood.
Adult ticks are good climbers. They crawl up grasses and shrubs—sometimes up to three feet high—in their quest for a blood meal. Deer are their preferred hosts but other large animals, such as humans and dogs, are also targets.
Contrary to popular belief, ticks don’t jump. They grasp onto a stem or leaf and wave their front legs in the air, waiting to make contact with a passing animal.
Lyme disease and biodiversity
Lyme disease isn’t caused by ticks, but by Borrelia burgdorferi, a bacterium found in forest animals. Mice are more effective than other small mammals at transmitting this bacterium to ticks. When mice are abundant, Lyme transmission increases.
Cary Institute research has shown that Lyme disease risk is lower when small mammal diversity is high (moles, shrews, voles, etc.) and predators such as hawks, owls, and bobcats are present. How can we increase small mammal diversity and predator abundance? Minimizing land fragmentation is a good place to start. When the landscape is divided up, biodiversity declines, predators disappear, and Lyme disease risk rises.
