COS 47-5
Non-native earthworm community dynamics in unglaciated eastern deciduous forests: Patterns of functional and species diversity
In previously-glaciated eastern deciduous forests the effects of non-native earthworms on ecosystem dynamics including nutrient cycling, forest floor depth, and plant species diversity are often documented. Less well examined are non-native earthworm communities in unglaciated portions of eastern deciduous forests. We have been surveying earthworm and plant communities in Southwest Virginia since 2007 in 16 sites ranging from small woodlots to large nature reserves.
Results/Conclusions
Although historically native earthworms have been reported in the region, we have found no native earthworms from about 2,000 individuals collected. We have found 14 species of European origins and one of Asian origins. To date, we have found no correlations between earthworm abundance or diversity and plant community metrics or topographical features. Nonetheless, commonalities among earthworm communities include 1) Lumbricus terrestris (aneic niche) or L. rubellus (epigeic niche) or both are present at every site and are often the most abundant species; 2) at most sites, either Octolasion spp. or Apporectodea spp. are the second most common Genera (all are in the endogeic niche) and these Genera are rarely in the same site; and 3) mean species richnesses (for adults 2.53 (0.67 SE) and for juveniles 2.10 (0.27 SE)) are relatively low compared to a regional species pool of 15 species. Taken together our results indicate that earthworm communities in unglaciated eastern deciduous forests can be exclusively non-native and have low functional redundancy (e.g., richness about equals functional diversity). Understanding the implications of non-native earthworm communities is important as these ecosystem engineers are a driver of ecosystem dynamics.