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Harvard Forest Symposium Abstract 2017

• Title: Assessing responses of native plant and soil microbial communities to different garlic mustard (Alliaria petiolata) eradication methods
• Primary Author: Erin Coates-Connor (University of Massachusetts - Amherst )
• Additional Authors: Mark Anthony (University of New Hampshire - Main Campus); Jason Aylward (Harvard Forest); Serita Frey (University of New Hampshire - Main Campus); Dustin Haines (University of Massachusetts - Amherst ); Kristina Stinson (University of Massachusetts - Amherst )
• Abstract:

  The eradication of the invasive biennial herb garlic mustard (Alliaria petiolata) and the restoration of invaded forest habitats present important linked challenges to land managers in North America. Root and leaf litter exudates from garlic mustard contain fungitoxic compounds that may inhibit root colonization by mutualistic mycorrhizal fungi for a number of native tree species. Removing garlic mustard by hand and by glyphosate herbicide application have both been used as eradication strategies, but both can disturb local plant and soil microbial communities. Further, garlic mustard exudates in the soil may have legacy effects on the soil microbial community even after eradication. There is a need to better understand the linked responses of plant and soil microbial communities to different eradication strategies in order to inform effective garlic mustard management practices.
  
  We established experimental eradication plots at seven forested sites in Northeastern temperate forest ecosystems. At each site, we established plots in communities invaded by garlic mustard as well as in adjacent non-invaded communities. In the invaded communities, we established two types of treatments at each site: eradication by hand-pulling and non-eradicated. In addition, we established a third type of treatment at a subset of the sites: eradication by spraying with glyphosate. We conducted pre-eradication plant censuses in 2013 and 2014, applied eradication treatments annually from 2014 through 2016, and conducted post-eradication censuses in 2015 and 2016. A third post-eradication plant census will likely be completed in 2017.
  
  Preliminary data show differences in plant community assemblages at invaded and non-invaded plots following eradication, which highlights the importance of designing effective garlic mustard control strategies.
  
  With these data, we are currently exploring the following questions:
  -Does glyphosate spraying vs. pulling produce different long-term patterns of garlic mustard density?
  -Does glyphosate spraying alter community composition and diversity relative to pulling, non-eradicated, and non-invaded communities?
  -Is there a relationship between plant and soil community composition, and does the relationship differ between different eradication treatments?
  -How does pulling affect plant and soil community composition and diversity reassembly relative to non-invaded and non-eradicated communities?

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