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Summary: Plant and Soil 212: 8599, 1999.
© 1999 Kluwer Academic Publishers. Printed in the Netherlands.
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Grazing in a porous environment. 2. Nematode community structure
Deborah A. Neher1,, Thomas R. Weicht1, Mary Savin2, Josef H. Görres2 and Jos´e A. Amador2
1Department of Biology, University of Toledo, Toledo, OH 43606, USA; 2Department of Natural Resources
Science, University of Rhode Island, Kingston, RI, USA
Key words: anhydrobiosis, trophic diversity, ecosystem function, free-living nematodes, mineralization, pore size
distribution, redundancy hypothesis
Abstract
The influence of soil matric potential on nematode community composition and grazing associations were ex-
amined. Undisturbed cores (5 cm diameter, 10 cm depth) were collected in an old field dominated by perennial
grasses on a Hinckley sandy loam at Peckham Farm near Kingston, Rhode Island. Ten pairs of cores were incubated
at -3, -10, -20 and -50 kPa matric potential after saturation for 2128 or 4258 days. Nematodes were extracted
using Cobb's decanting and sieving method followed by sucrose centrifugal-flotation and identified to family or
genus. Collembola and enchytraeids present were also enumerated because they are grazers that reside in air-filled
spaces. Direct counts of bacteria and fungi were made to estimate biovolume using fluorescein isothiocyanate
and fluorescein diacetate stains, respectively. Trophic diversity and maturity indices were calculated for nemat-
ode communities. Three patterns of matric potential effect were observed for nematode taxa. One, there was a
consistent effect of matric potential for all seasons for Alaimus, Monhysteridae, Prismatolaimus, Paraxonchium
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