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Harvard Forest REU Symposium Abstract 2018

• Title: Does Trifolium repens facilitate the invasion of Cirsium vulgare? A spatial and greenhouse study.
• Author: Shreena Pyakurel (Mount Holyoke College)
• Abstract:

  Many invasive species are particularly adept at accessing soil resources and use these resources to establish and expand their distribution. A grassland study at Harvard Farm in Petersham, Massachusetts, has recorded changes in community composition with grazing and mowing since 2014. In that period the percent cover of invasive species has increased every year and across all biomass removal treatments at the Harvard Farm. Our goal is to determine whether a nitrogen fixer, Trifolium repens, facilitates the growth of an invasive species, Cirsium vulgare. In the greenhouse, we examined how soil, litter, and live individuals of T. repens affect growth of C. vulgare. In addition, to the greenhouse experiment we conducted 50m belt transects across Harvard Farm’s three treatment areas (constant grazing, mowing, and rotational grazing) and surveyed percent cover of T. repens and stem counts of C. vulgare. Our results in the greenhouse generally showed a negative impact on C. vulgare growth in the presence of T. repens soil and litter. However, there is a positive trend with the presence of live Trifolium. In the field there was a slight positive correlation between the density of T. repens and C. vulgare in the grazing treatments, however there was a slight negative correlation in the constant grazing and mowing treatments. We hope to conduct further analysis to examine whether effects of T. repens vary for C. vulgare in different life stages.

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