Garlic Mustard and its Effects on Soil Nematode Communities - Dan Bruzzese

Abstract:

Soil nematodes are highly responsive to soil biota populations and
microenvironmental factors. The invasive plant, Garlic mustard (Alliaria petiolata) has
invaded many forests across the Eastern United States and can change soil communities
via allelopathy. Glucosinolates and their by-products are responsible for garlic mustard’s
allelopathy and are commonly used as nematicides. I proposed that garlic mustard
reduces the abundance soil nematodes and their taxonomic diversity. I also expected
garlic mustard to cause a shift in the trophic spectrum of the nematode community by
reducing the amount of fungal feeding and plant feeding nematodes. Twelve 20x20 meter
paired control and garlic mustard plots were created in Hamilton College’s Kirkland and
Rogers Glens. Nematodes were extracted from collected soil samples and soil organic
matter and pH were also determined. The nematode community was evaluated using
measures of abundance and taxonomic diversity. My results highlight the variation found
within nematode communities. Garlic mustard was found to decrease nematode
abundance and plant feeding trophic group abundance, but was also found to increase the
bacterial feeding trophic group. Garlic mustard communities were more diverse when
compared to controls because many of the control communities were dominated by plant
feeding nematodes. These measures of community are also associated to increased pH
and organic matter in garlic mustard plots.