Species diversity and random distribution of microfauna in extremely isolated habitable patches on Antarctic nunataks
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Populations of metazoan microfauna (nematodes, rotifers and tardigrades) are patchily distributed on mountain outcrops penetrating the ice sheet (nunataks) in continental Antarctica. The abundance and fauna composition of microscopic animals vary greatly also among samples from similar types of habitats. Occurrence of similar seemingly habitable sites without microfauna and sites with various combinations of animal taxa indicates that stochastic colonization processes as well as local environmental factors and historical factors influence faunal composition in a specific habitable patch. The abundance of nematodes, rotifers and tardigrades in various combinations of co-occurrence was analyzed. One objective was to investigate if biotic interactions structuring these simple communities could be observed. The 368 samples analysed originate from three kinds of habitats, viz. mosses, ornithogenic soils and fellfield soils, obtained from 14 nunataks in Dronning Maud Land, East Antarctica. It is suggested that high population densities of any of the three animal groups, when they were found alone and lower densities, when they coexisted with other taxa could indicate the presence of competition or predation. However, the great variability in microfauna densities for similar habitable patches made it difficult to find significant differences among population densities in samples with varying complexity.
KeywordsAntarctic nunataks Competition Fellfield Moss Nematodes Ornithogenic soil Predation Rotifers Tardigrades
We are grateful to the Swedish Polar Research Secretariat for providing transport and facilities for K. Ingemar Jönsson, who conducted the field sampling in Antarctica in 2001/02; for Cecilia Eriksson, who made the sampling in 1993/94 and 1996/97 and for Göran Thor, who made the sampling in 1991/92. Kent Larsson is thanked for providing the map. Ingegerd Sohlenius is thanked for technical assistance. Helpful comments on the manuscript were given by two anonymous referees.
- Dastych H, Harris JM (1995) A new species of the genus Macrobiotus from inland nunataks in western Dronning Maud Land, continental Antarctica (Tardigrada). Entomol Mitt Zool Mus Hamb 11:175–182Google Scholar
- Hanski I (1999) Metapopulation ecology. Oxford University Press, New York, pp 313Google Scholar
- Hiller A, Hermichen WD, Wand U (1995) Radiocarbon-dated subfossil stomach oil deposits from petrel nesting sites: novel paleoenvironmental records from continental Antarctica. Radiocarbon 37:171–180Google Scholar
- Kinchin IM (1994) The biology of tardigrades. Portland Press, London, pp 186Google Scholar
- Lewis MA (1997) Variability, patchiness, and jump dispersal in the spread of an invading population. In: Tilman D, Kareiva P (eds) Spatial ecology. Princeton University Press, Princeton, pp 46–74Google Scholar
- Porazinska DL, Wall DH, Virginia RA (2002b) Invertebrates in ornithogenic soils on Ross Island, Antarctica. Polar Biol 25:569–574Google Scholar
- Ryan PG, Steele WK, Siegfried WR, Vogel JC (1992) Radiocarbon dates of snow petrel regurgitations can reveal exposure periods for nunataks in Antarctica. S Afr J Sci 88:578–580Google Scholar
- Ryss A, Boström S, Sohlenius B (2005) Tylenchid nematodes found on the nunatak Basen, East Antarctica. Ann Zool 55:315–324Google Scholar
- Sohlenius B (1979) A carbon budget for nematodes, rotifers and tardigrades in a Swedish coniferous forest soil. Holarct Ecol 2:30–40Google Scholar
- Sohlenius B (1989) Interactions between two species of Panagrolaimus in agar cultures. Nematologica 34(1988):208–217Google Scholar