Invertebrates in ornithogenic soils on Ross Island, Antarctica

Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499, USA
Polar Biology (Impact Factor: 2.07). 07/2002; 25(8):569-574. DOI: 10.1007/s00300-002-0386-7

ABSTRACT A habitat suitability model developed for soil biotic communities in the McMurdo Sound region, Antarctica predicts that soil moisture, organic carbon, and salinity exert control on the abundance and complexity of soil food chains. The model has been intensively tested in dry and carbon-poor soils of the Dry Valleys. To determine the influence of moisture and soil organic mater in wetter soils with high C content, invertebrates (nematodes, rotifers, and tardigrades) from soil samples collected in and near penguin rookeries on Ross Island (Cape Bird, Cape Crozier, and Cape Royds) were examined. Invertebrates were present in less than 50% of all collected soil samples. Although four nematode species were identified (Eudorylaimus antarcticus, Panagrolaimus davidi, Plectus antarcticus, Scottnema lindsayae), only populations of Panagrolaimus davidi were observed in soils collected from within penguin rookeries. Abundances of Panagrolaimus davidi and rotifers differed among rookeries, and year of sampling had a significant effect only on the populations of Panagrolaimus davidi. There were no temporal differences in soil moisture and soil chlorophyll a concentrations within each rookery or across rookeries. No invertebrates were correlated with soil moisture or chlorophyll a at the time of collection. Counter to our expectations, higher nutrient, organic matter, and moisture levels did not result in more abundant and diverse invertebrate communities in the rookery soils. It appears that excessive accumulations of nutrients, creating high soil salinity, may limit soil invertebrate presence within active rookeries.

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