The Swiss Action Plan on Plant Protection Products (AP-PPP) includes a measure for long-term monitoring of PPP residues in agricultural soils and their effects on soil fertility. Within this measure the ConSoil project proposes an integrated approach for combining risk-based reference values with an ecological and ecotoxicological bioindicator toolbox. The current report details the different steps and considerations for selecting and proposing an initial toolbox of bioindicators.
The selection, scoring and ranking of organism groups is necessary for their prioritization as bioindicators. The scoring includes previously established links of in-soil organisms and plants to ecological soil functions and also integrates the importance of these links for soil fertility according to various Swiss stakeholders. The stakeholder evaluation was conducted through a questionnaire and the results as well as the scoring of organisms are presented and described. From this scoring, a priority list was established and possible bioindicator methods for each organism group were discussed in a workshop with several national and international experts in soil ecology and ecotoxicology. Finally, an initial toolbox of bioindicators is proposed considering different sampling strategies and limitations.
The bioindicator toolbox will be tested in pilot studies to evaluate the performance, variability and sensitivity of the proposed methods. The pilot studies also aim to refine and establish tools for the interpretation of effects such as toxicity thresholds. Based on these pilot studies and in collaboration with project partners and the federal offices the toolbox will be further refined.