Earthworms are not native to formerly-glaciated regions of North America. Their presence is primarily due to anthropogenic activities such as agriculture, sport fishing, and recreation. While worms can be beneficial for improving garden soils, they can be devastating to forest floor ecosystems and may impact plant and animal biodiversity and abundance. During the summer of 2010, sixty-six sites within the Cleveland Metroparks were studied for soil composition, plant habitat quality, and plant community composition. Earthworms and soil invertebrate communities were also sampled from these sites. Earthworm specimens (N=897) were analyzed for prevalence, assemblage composition, and biomass. Invertebrate community composition was analyzed for 60 of the 66 sites. Of particular interest is a recent arrival of the invasive earthworm of genus Amynthas. An allometric equation relating AFDM to length was developed from a set of specimens taken from northeastern Ohio forests in 2009, consisting of both A. hilgendorfi and A. agrestis. I hypothesize that sites with larger populations and diversity of earthworms will depress the richness and diversity of soil invertebrate communities as well as the percentage of sensitive plants, while boosting the prevalence of tolerant and non-native plants.
The Amynthas allometric equation reliably predicts (R2=0.959) AFDM from length measurements for the sample population (N=160) of A. hilgendorfi and A. agrestis and is useful for estimating biomass of subsequent Amynthas samples. By supplementing the aforementioned equation with previously published equations for other identified genus and species of earthworms, approximate biomass will be determined at each site. 55 out of 66 sites sampled contained worms. Earthworm densities varied between 0 and 666 individuals per square meter (µ=132/m2, σ=167/m2). Analysis of relationships between earthworm communities and their impacts upon plant and soil invertebrate communities are ongoing.