High-Arctic gamasid mites (Acari, Mesostigmata): community composition on Spitsbergen, Svalbard

This study investigates assemblages of mesostigmatid mites on Spitsbergen, in the Arctic archipelago of Svalbard, Norway. Soil samples were collected from three areas with differing vegetational communities in Adventdalen. The greatest gamasid mite density and species diversity was observed at the location with the richest vegetation cover, Dryas octopetala heath, where 10 species were collected and there was a mean total gamasid mite density of 1000 individuals per m(2). The vegetation-poor saline meadow site revealed five species and had a mean total gamasid mite density of 130 individuals per m(2). The floristically more diverse Luzula tundra site yielded four species and had a density of 270 individuals per m(2). The most frequently found species were Zercon forsslundi, Arctoseius haarlovi and A. weberi. Results indicate that even in High-Arctic regions, where species diversity is less than at lower latitudes, there is specialization amongst the gamasid mite community depending on local environmental conditions. Apart from isolated checklists, only sporadic information concerning the ecology of High-Arctic gamasid mites is available. Many of the gamasid mites reported from Svalbard are relatively rare.