The aim of this project was the improvement of the preconditions for the protection of the habitat function of soil as described in § 2 of the German Federal Soil Protection Act (1998), in particular in two ways: first, suitable biological indicators (i.e. organism groups) for the assessment of soil quality had to be identified. Second, reference values useful for selected biotope types had to be established in order to decide whether a soil did fulfil the habitat function or not. Finally, this work was intended to improve the German ‘National strategy for biological diversity’, e.g. by broadening soil biological monitoring at existing permanent soil monitoring sites (BDF). In order to reach this aim, existing methods and concepts (including the legal background) for using soil biodiversity for soil quality assessment were compiled. In parallel, a database was set up, in which soil biological data coming from BDF of several German states as well as from the literature (especially from the partner institutions) on Collembola, Oribatida, Lumbricidae and Enchytraeidae was compiled and critically discussed. The biogeographical distribution of selected species from the four invertebrate groups and their distribution in relation to the most important site factors (land use, pH, texture, organic matter) were presented in maps and tables (similar information for additional species was compiled in an annex). Based on the statistical (multivariate) evaluation of the relationship between the distribution of these species and site and soil properties, proposals for reference values were made (differentiated according to biotope types and land use). Since it was not possible to perform a similar evaluation for microorganisms, work with this group focused on a critical discussion of available methods used for the recording of their diversity. Finally, a deficit analysis concerning the state of the art of soil biodiversity assessment in Germany was performed. A detailed proposal how to improve soil biological monitoring was made, focusing in particular on the permanent soil monitoring sites. In this context, ecosystem services provided by soil organisms were also considered.
The final report of this project is available [read more].