The macrofauna decomposer food web on alpine pastureland

Julia Seeber, Stefan Scheu (Universität Göttingen), Erwin Meyer (PI)


Based on profound knowledge on the abundance and biomass of the soil macrofauna as well as on the humus forms on alpine pastureland in the Central Alps (Kaserstattalm, Stubai Valley) the proposed study aims
(1) to point out the trophic relations of the decomposer communities under the impact of land-use changes using stable isotope analysis and
(2) to elucidate interactions between saprotrophic soil animals regarding different litter qualities with mesocosm experiments.

The widespread assumption is that due to unfavourable climatic conditions at the alpine treeline, poor quality of especially dwarf shrub litter on abandoned pastureland and the loss of keystone species, such as   as earthworms, decomposition is slowed down. The absence of  these "engineers" may be one of the most significant functional changes.  This leads to an accumulation of organic material, an increase in soil  acidity and the development of more differentiated humus forms consisting of several horizons  (moders and mors). However, earlier studies on abandoned sites in the research area have shown that mull humus can still be found more than ten years after abandonment, the invasion of dwarf shrubs and afforestations. Also the loss of  keystone species such as endogeic-anecic earthworms could  not generally be confirmed .

Therefore the trophic diversity and the interaction complexity of   large saprotrophic soil animals mainly responsible for litter fragmentation and bioturbation on differently managed alpine pastureland  are to be assessed.

The rationale of  this study is to undertake research on the functioning of decomposition processes at  the alpine treeline, leading to improvements in fundamental understanding on diversity-function relations under changing conditions in an ecologically sensitive system.

Funding: FWF Logo

Makrofauna Zersetzernahrungsnetz


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