Article

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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    [Show abstract] [Hide abstract]
    ABSTRACT: Th e structural and functional parameters of nematode assemblages from Deschampsia microhabitats of polar deserts in the Arctic and Antarctic, as well as from nival moun-tainous habitats in the southern Taymyr Peninsula, Siberia, were compared. Common features of all communities were: low taxonomic richness, with antarctic microhabitats being generally poorer; equal degrees of faunal similarity between the diff erent locali-ties both in the arctic and antarctic hair-grass communities suggesting that most of the genera were polytopic; variability of dominance structure between the diff erent types of polar desert sites, as well as superdominance patterns observed, with one genus (Plectus) always being present among the dominants; superdominance better pronounced on the Putorana Plateau and Livingston Island; overall dominance of bacterial feeders followed by omnivorous nematodes and fungal feeders; very low percentages of predatory or parasitic nematodes of higher plants; nematode general opportunists (the c-p 2 group) dominated and were the most typical dwellers of polar microhabitats; comparatively well structured food webs, undisturbed and moderately enriched environment. However, the nematode assemblages of D. antarctica and D. borealis diff ered in their taxonomic structure and decomposition pathways being exclusively fungi-dominated in all arctic sites and characterized by prevailing bacteria-driven decomposition channels in the Antarctic.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The structural and functional parameters of nematode assemblages from Deschampsia microhabitats of polar deserts in the Arctic and Antarctic, as well as from nival moun-tainous habitats in the southern Taymyr Peninsula, Siberia, were compared. Common features of all communities were: low taxonomic richness, with antarctic microhabitats being generally poorer; equal degrees of faunal similarity between the diff erent locali-ties both in the arctic and antarctic hair-grass communities suggesting that most of the genera were polytopic; variability of dominance structure between the diff erent types of polar desert sites, as well as superdominance patterns observed, with one genus (Plectus) always being present among the dominants; superdominance better pronounced on the Putorana Plateau and Livingston Island; overall dominance of bacterial feeders followed by omnivorous nematodes and fungal feeders; very low percentages of predatory or parasitic nematodes of higher plants; nematode general opportunists (the c-p 2 group) dominated and were the most typical dwellers of polar microhabitats; comparatively well structured food webs, undisturbed and moderately enriched environment. However, the nematode assemblages of D. antarctica and D. borealis diff ered in their taxonomic structure and decomposition pathways being exclusively fungi-dominated in all arctic sites and characterized by prevailing bacteria-driven decomposition channels in the Antarctic.