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Harvard Forest REU Symposium Abstract 2018

  • Title: Title: Impact of Cirsium vulgare on the Plant Community Structure of a New England Grassland Ecosystem
  • Author: Seanne R Clemente (University of Guam)
  • Abstract:

    With the decline of agriculture and the subsequent mass reforestation of New England in the past century, the extent of the region’s grassland ecosystems has been markedly reduced. These grasslands serve as crucial habitats and breeding grounds for a large variety of regional wildlife species and have become a target for conservation and management to avoid returning to a forested landscape. Landscape management regimes (such as mowing or cattle grazing) remove woody biomass and reintroduce agricultural pressures that historically maintained these grasslands. A potential issue with this solution, however, is that such regimes can facilitate the spread and establishment of invasive species. Here, we investigate the impact of invasive bull thistle (Cirsium vulgare) on the plant community structure of a Central Massachusetts grassland maintained by yearly mowing. We conducted plant censuses in plots with and without C. vulgare present and determined that total species richness is significantly higher in plots containing C. vulgare. This was likely explained by differences in non-native species richness, which was significantly higher in the presence of C. vulgare. Through a greenhouse study, we aimed to determine whether C. vulgare affected the growth and establishment of native and non-native plants differently. We found that litter had a negative effect on the growth of three native plants (Oxalis stricta, Potentilla simplex, Erigeron canadensis) and three non-native plants (Rumex acetosella, Rosa multiflora, Polygonum aviculare). A stronger negative effect observed in native plants, but future measurements of plant biomass will confirm the significance of this trend.

  • Research Category: Biodiversity Studies; Conservation and Management; Invasive Plants, Pests & Pathogens