D. J. Russell et al.


David J. Russell Senckenberg Museum für Naturkunde Görlitz,
Postfach 300 154, 02806 Görlitz, Deutschland;

Karin Hohberg Senckenberg Museum für Naturkunde Görlitz,
Postfach 300 154, 02806 Görlitz, Deutschland;

Michael Elmer Brandenburg University of Technology,
Postfach 101 344, 03013 Cottbus, Deutschland


Primary colonisation of newly formed soils by actinedid mites


In the brown-coal open-cast mining district near Cottbus, Germany, an artificial, experimental water-catchment system was constructed in 2005. The purpose of the experiment is to observe the development of the soil ecosystem during simulated primary succession. Within these studies the development of the soil  fauna  has  been  monitored  since  late  2005,  of  which  the  results  regarding  actinedid  mites  are presented here. Actinedida represented the major microarthropod group colonising the newly developing soils, having been present within months after exposition of the substrates to the surface, albeit in very low  densities  and  only  in  sporadic  samples.  Initially,  species  richness  was  also  extremely  low,  with practically  only Nanorchestes sp.  und  Speleorchestes sp.  present. Three  years  after  site  initiation,  the abundances and species richness increased significantly, although they were still low compared to mature soils.  The  microarthropod  communities  continued  to  be  strongly  dominated  by  actinedid  mites  and colonisation of the soils remained spatially heterogeneous. The sporadic individual-richness was mostly caused  by  strong  population  development  of  single  species  in  a  few  samples,  e.g.,  Siteroptes sp.  and Bakerdania sp. The abundance and distribution of Nanorchestes sp. originally increased strongly in the first  two  years.  However,  as  many  more  species  were  found  thereafter,  the  density  of  this  species decreased  briefly;  dramatically  in  samples  containing  high  densities  of  Siteroptes sp.,  indicating successional species replacement. Remarkable is the occurrence of species such as Cheletomimus vescus, Hawaiieupodes thermophilus and  Xerophiles ereynetoides,  which  are  rare,  most  likely  xero-thermophilous species adapted to nutrient-poor soils. The results described here represent only those of the first 2.5 years and sampling and evaluation will continue.


Actinedida, succession, sand, colonisation