Johanna Fickenscher
Introduced exotic plants can spread rapidly and may have devastating effects to local biotic communities. Since disturbance has been shown to facilitate the spread of exotic plants, earlysuccessional habitats (including shrublands and young forests) are especially vulnerable to invasions by exotic plants. Early-successional habitats are critical to an array of native plant and animal species. In New England these habitats are increasingly scarce and are subjected to management regimes (e.g., tree harvests, mowing, prescribed fires). Consequently, these habitats are vulnerable to invasions by exotic plants that may alter community composition and subsequent interactions. Wildlife species that depend on plants as a food source, such as insects, might not be able to consume invasive plants, or might not recognize invasive plants as a food source. This may result in fewer insects in areas where exotic shrubs have invaded. Animals that feed on insects (especially nesting songbirds) may then be negatively affected because their food source is reduced. Thus, invasive plants may have devastating consequences for whole biotic communities. Preliminary sampling revealed that insects may be as much as three times more abundant and species richness greater on native than exotic shrubs. During the summer of 2007, insects were sampled in four early-successional habitats in southeastern New Hampshire. Two sites were highly invaded by exotic shrubs (>90% exotic shrubs), and two sites were composed primarily of native shrubs (<25% exotic shrubs). Insects were sampled using flight-intercept trapping and beat/sweeping captures. We are now comparing insect abundance and taxonomic richness among these sites.
Keywords: EARLY-SUCCESSIONAL HABITAT, INSECT BIOMASS, INVASIVE SHRUBS, INSECT SPECIES DIVERSITY
