Terrestrial invertebrate abundance across a habitat transect in Keble Valley, Ross Island, Antarctica

The abundance and distribution of soil invertebrates was examined along a transect in Keble Valley, Cape Bird, Ross Island, Antarctica during and after snowmelt. During snowmelt, streams were flowing across the transect, and the moisture environment was highly heterogeneous, whereas after the cessation of stream flow the moisture environment became more homogeneous. Of the seven groups of invertebrates examined, only the prostigmatid mite Stereotydeus mollis showed any redistribution between the two sampling points. The streams had higher water availability, higher soil chlorophyll-a content, higher organic content and lower surface salinity than the areas beside the streams. Nematode (Panagrolaimus davidi), soil rotifer and soil protozoan abundance was significantly associated with this area of high productivity, and the cryptostigmatid mites S. mollis and Nanorchestes antarcticus were found near the stream centres. By contrast, the collembolan Gomphiocephalus hodgsoni was found at riparian margins, and it is hypothesised that this could be due to habitat and food preferences.