The Soil Fauna of an Alpine Glacier Foreland: Colonization and Succession

Abstract

We investigated the development of soil macrofauna and mesofauna in the successional chronosequence of an Alpine glacier foreland located above the treeline. Sampling transects 10 m long were established at eight successional stages from 4 to 150 yr of age since deglaciation, and in addition two reference sites in front of the terminal moraine. Within the first 50 yr, macrofauna biomass and mesofauna abundance increased rapidly, attaining levels typical for all older stages (macrofauna 0.5–7 g m–2, microarthropods 50–120 103 ind. m–2). Among the macrofauna nematoceran Diptera were dominant at most sites, only the early colonizing stages being dominated by carabid and lepidopteran larvae and enchytraeids. Acari were more abundant than Collembola. Temporal sequences of occurrence were documented for macrofauna families and for collembolan species. Successional age was the major determinant of community composition, additional influences being local variations in microclimatic conditions and soil properties. Biomass increased over the short alpine summer, but community composition remained largely constant. The high aggregation of soil fauna affected the precision of abundance estimates. An outline of the trophic structure of evolving soil communities is presented.