Effects of Removing Invasive Shrubs on Microclimate and Tick Populations

Non-native plants are altering the characteristics of ecosystems in New England. These invasive species are notorious for outcompeting native species by growing quickly and in an uncontrollable fashion, creating dense invasive thickets. Our study investigates the impact that forest management has on tick populations. It is known that ticks tend to thrive in climates with higher humidity, which can be the result of dense shrub thickets. The dense understory structure created by nonnative plants can increase humidity and protection from extreme temperatures, thereby creating a more favorable microclimate for ticks. Microclimate characteristics may explain why prior studies have found a positive relationship between the amount of ticks and invasive thickets. We hypothesize that the removal of invasive shrubs will support fewer ticks than where invasive shrub thickets have not been removed due to the changes in microclimate. The experimental forest was broken up into several treatments: native forest (reference/control), unmanaged forest (primarily invasive plant species honeysuckle and privet), and managed forest ( primarily invasive shrubs removed within the past two years). Over the course of five weeks (March through April) the microclimate was measured within these plots by recording air temperature, soil temperature and air humidity, as well as sunlight levels within each plot. We also quantified tick populations through the flagging method. Trends that were identified from data analysis early on indicate that the managed and unmanaged treatment show a clear difference in micro-climate characteristics as well as tick abundance. Of the three treatments, the managed treatment has yielded the highest number of ticks from flagging methods.