PARENT SESSION
Poster Session #48: Urban Ecology.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC
8
Earthworm diversity and abundance in the urban landscape.
Szlavecz, Katalin1, Pouyat, Richard*,2, 1 The Johns Hopkins University, Baltimore, MD2 USDA Forest Service, Baltimore, MD
ABSTRACT- In North America land use change is an important factor influencing earthworm distribution, especially exotic species. During 2001-2002 we measured earthworm densities and soil characteristics in .04-ha circular plots in the Baltimore City metropolitan area using a stratified randomized design by land-use type (urban and rural deciduous forests, recreational parks, residential lawns, and abandoned agricultural fields). We found a total of 15 species in the 90 plots (0.25 m2) sampled. In addition, another 6 species were found in grab samples in areas near the plots. Of the species identified, 12 were exotic species from Europe and Asia, which dominated in urban habitats. Native species were rare and were usually found in specialized habitats, such as riparian zones. The highest densities and live weight biomass values were 136 individuals m2 and 180 g/m2, and 103 individuals m2 and 76 g/m2 in the abandoned agricultural and urban forest land-use types, respectively. In general, urban landscape values varied greatly, however, significantly (P = 0.05) higher densities were found in urban than in rural forest patches. Soil characteristics also varied among land-use types, but were not statistically correlated with earthworm densities at least for the sampling intensity used in this study. Bulk density ranged from 1.08 in forest to 1.29 mg/m3 in residential land-use types, respectively. Base cation concentrations were near or above 2000 mg/kg in the residential type. These concentrations were 60% higher than concentrations found in the forest land use type. Organic matter concentrations in forest land-use types were over 20% greater than the lowest concentrations occurring in residential lawns. In the Baltimore City metropolitan area, earthworm densities and biomass appear to be more related to land use than to the range of soil characteristics measured in plots sampled in this study.
KEY WORDS: earthworms, urban ecosystems, soils, baltimore ecosystem study lter