Habitat associations of Ixodes scapularis (Acari: Ixodidae) in Maine

The habitat associations of Ixodes scapularis Say (= I. dammini Spielman, Clifford, Piesman, and Corwin) were examined at the northern edge of its range. We assessed the association of habitat features with the abundance of ticks by flagging for questing adult L scapularis at three sites in coastal Maine from 1998 to 2000 along 27 305-m transects. Multivariable logistic regression indicated that probability of tick abundance was greater in the presence of shrub layer, canopy closure >50%, deciduous litter, forest grasses, and moist-soil ferns. In a second model that related L scapularis abundance to canopy- and shrub-layer species, probability of tick abundance was greater in the presence of Japanese barberry Berberis thunbergii DC, winterberry holly Vex verlicillata L. (Gray), and Eurasian honeysuckle Lonicera spp., and less with the presence of eastern hemlock saplings Tsuga canadensis L. (Carr.). These associations were true despite variation in deer abundance as indicated by deer pellet group counts. Natural resource managers should be aware that landscape changes, including the invasion by exotic vegetation, might create favorable tick habitat. These findings could prove helpful in assessing local risk of exposure to this vector tick.