Distribution patterns of microfauna (nematodes, rotifers and tardigrades) on nunataks in Dronning Maud Land, East Antarctica

Abstract

In a previous paper the occurrence of nematodes, rotifers and tardigrades in 29 samples from nunataks in Dronning Maud Land, East Antarctica taken 1991/1992 was recorded. In this study, a more thorough description of animal distribution is possible by adding 64 new samples (1993/1994), thus increasing the total number from these studies to 93 soil samples from 11 nunataks. The number of species recorded from the area has now increased from 27 to 34. The populations were patchily distributed and the species composition differed between nunatak areas in Vestfjella and Heimefrontfjella. In most samples only one or a few species of nematodes or tardigrades were found. The number of rotifer species in a particular sample varied from nought to seven. Rotifers occurred in most of the samples (76%) with a maximum density of 750 specimens/gram dry weight. The nematode distribution was more restricted. Nematodes were found in high abundance on only four of the nunataks and occurred in 35% of the samples with a maximum density of 210 specimens/gram dry weight. Tardigrades were found in 39% of the samples with a maximum density of 580 specimens/gram dry weight. Some of the tardigrade species were widely distributed, whereas others were found only on specific nunataks. The distribution pattern of the fauna on two of the nunataks, Basen and Fossilryggen, was studied in greater detail and the results showed little difference in peak abundance and species composition between samplings carried out during two southern summer seasons.