Terrestrial invertebrates along a gradient of deglaciation in Svalbard: Long-term development of soil fauna communities

The recent deglaciation of large polar areas has exposed stretches of land, allowing spontaneous primary succession. The exposed substrate is colonized by soil biota participating in soil formation - a process in which soil characteristics and the biotic community affect each other mutually. Soil fauna was studied along three transects in glacier valleys around Petunia Bay on Svalbard in the High Arctic, representing chronosequences of soil development on plots deglaciated for ten to approximately ten thousand years. Community development was characterised by progressive addition of species, with many pioneer species remaining present throughout soil development. Generally, the abundance and species richness of soil animals increased from the initial to the well-developed sites. Altogether 93 taxa of soil fauna were identified, including 21 species of rotifers, 38 genera of nematodes, 8 species of tardigrades, 21 species of springtails and 4 species of enchytraeids. Rotifers were the earliest colonizers, found already in the initial stage, followed by nematodes in plots several tens of years old. They were followed by tardigrades, which - although in low abundances - established populations in the third stage of the chronosequences, 10(3)-year-old. Collembolans formed stable populations at the end of the chronosequence in the third and fourth stages, 10(3) to 10(4) years old. Enchytraeids only appeared at the end of the chronosequence. Assemblages were significantly driven mostly by the age of the plot, association with a given transect and nutrient availability.

Automated summary

The recent deglaciation in large polar areas has allowed for spontaneous primary succession to occur, with the soil biota participating in soil formation. The study of soil fauna on Svalbard in the High Arctic revealed a progressive addition of species during soil development, with pioneer species remaining present throughout. The assemblages of soil animals were mainly influenced by the age of the plot, association with specific transects, and nutrient availability.