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Harvard Forest Symposium Abstract 2006

  • Title: Land-use legacies, present-day forest fragmentation and harvesting, and invasive species
  • Primary Author: Robert McDonald (Harvard Forest)
  • Additional Authors: David Foster (Harvard University); Glenn Motzkin (University of Massachusetts - Amherst )
  • Abstract:

    Non-native invasive species may exert detrimental effects on human and natural systems, and an accurate understanding of the factors controlling their presence is crucial for management decisions and for predicting future invasions. However, the relationship between non-native invasive species and landscape-level disturbances like forest harvesting, historical land-use, and present-day forest fragmentation, is not well understood. In 148 sites throughout western Massachusetts, almost half (49.3%) had at least one non-native invasive plant present, but in only 9% were invasives abundant. We used logistic regression to model the probability of finding the four most common species: Japanese barberry (Berberis thunbergii DC), glossy buckthorn (Rhamnus frangula L.), multiflora rose (Rosa multiflora Thunb. ex Murr.), and oriental bittersweet (Celastrus orbiculatus Thunb.). Bedrock-type was the most important predictor of invasive presence, with calcareous sites being more likely to have these species. Historical land-use legacies (i.e., whether a site was formerly plowed, pastured, or continuously wooded) were also important predictors of whether a site supports non-native plant species, with sites that were more intensively modified for historical agriculture more likely to have these species. Finally, the structure of the current forested landscape (i.e., the amount of forest within a 10 km buffer around a site) is important, with sites that are surrounded by more forest being less likely to have these species. Our results stress that the regional patterns of an invasive plant species distribution results from a complex function of edaphic conditions and both past and present land-use.

  • Research Category: Invasive Plants, Pests & Pathogens