Earthworms, soils and N-cycling in remnant forest patches in the Baltimore Metropolitan Area
Katalin Szlavecz, Sarah Placella, Richard Pouyat, Vincent Giorgio, Peter Groffman, and Csaba Csuzdi
Soil organisms strongly respond to spatial heterogeneity of their habitat. The objective of our study was to assess the effects of anthropogenic patchiness on composition and abundance of soil arthropods and earthworms. In 2003 we conducted field surveys on lawns, flowerbeds, and forest patches in the Cub Hill neighborhood. The twelve households selected differed in their lawn maintenance practices. Sampling took place in April and in June. Earthworm samples were taken from 25cm x 25 cm quadrats using mustard solution. For macroarthropods we placed three pitfall traps per hosusehold: one in the front, one in the back, and one on the side of the property. The traps operated for a week. Mesofauna samples were taken using a 5 cm diameter soil core. Soil moisture, temperature and pH were measured at the time of sampling.
From spring to summer earthworm abundance increased more dramatically in the forest than in the lawns. This was mostly due to the appearance of the introduced Asian species, Amynthas hilgendorfi, which occurs almost exclusively in the forest. Macroarthropods were also more abundant in the summer than in the spring, with the exception of millipedes. The total density mites corresponded with the degree of lawn maintenance. High maintenance lawns had the highest density (comparable to that of forests). The largest proportion of Acari, the Cryptostigmata, was mostly responsible for this pattern. Density of oribatid mites also negatively correlated with soil organic matter. Abumdance of total Collembola also responded to lawn maintenance.
Keywords: Earthworms, macroarthropods, microarthropods, lawn care, suburban neighborhood

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