LTREB Renewal: Resource pulses and the dynamics of rodents, ticks, and Lyme-disease risk in oak forests

Lyme disease is one of the most frequently reported infectious diseases in the United States, with roughly 500,000 new cases each year. Risk of exposure to Lyme disease and associated tick-borne diseases varies dramatically from place to place and from year to year. Research that determines what causes this variation is critical in preventing and managing these diseases.

The ticks that transmit these diseases to people feed on many different animal species, but rodents like white-footed mice and chipmunks are the most important in boosting tick numbers and tick infection. Numbers of these rodents, in turn, depend on the supply of acorns and other tree seeds. Weather and climate affect the trees, the rodents, and the ticks directly.

This research is designed to improve the ability to predict Lyme disease risk, which can have major implications for human health. It asks how each stage in the complex life cycle of the tick responds to rodent numbers and to climate, how the rodents are affected by their predators, and how long-term changes in the forest, including the species and ages of the trees, affect the food supply for rodents and deer.

The research will collect new data on numbers and survival of both on-host and off-host ticks in the larval, nymphal, and adult stages and integrate these into full models of tick population changes through time. It will ask how temperature and humidity on the forest floor affects survival of these life stages. It will continue adding to a 30-year data set asking how the production of seeds by forest trees changes as the climate and relative abundances of tree species change over time.

The occurrence of predators such as bobcats, foxes, and coyotes will be monitored using camera traps to investigate possible impacts on rodents, ticks, pathogen prevalence, and Lyme disease risk. The data will be used to develop and evaluate forecasts for Lyme disease risk from the component parts.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.