Why this SESSS?
The risk assessment of chemicals in soil is based on the results of a limited number of single-species toxicity tests. These results have to be extrapolated to effects at higher levels of biological organization (populations, communities, ecosystems), and at different spatial scales in the (agricultural) landscape. There also is a wish to extrapolate effects on structural properties of ecosystems to potential impacts on ecosystem functioning, nowadays indicated with the term Ecosystem Services.
This practice requires the application of recent developments in the knowledge and understanding of soil biodiversity, as well as its role in the functioning of soil ecosystems, which has considerably increased in the last decades. Significant insights have been obtained, for instance, in the relationship between above- and below-ground components of the soil ecosystem. In addition, the ecotoxicological toolbox for assessing chemical effects on soil invertebrates also has grown, resulting in a higher availability of higher tier tests. Both the currently available ecological knowledge, and the availability of new laboratory test methods, may prove useful input to develop models for predicting effects at higher levels of biological organization, using data from single-species laboratory tests.
Post-registration monitoring is often mentioned as a tool for identifying side effects of Plant Protection Products, not foreseen in the environmental risk assessment. Such a monitoring cannot do without a proper baseline or reference, indicating the level of normality, both in terms of species diversity as well as ecosystem functioning. In the last decades, an extensive amount of data has been gathered on the biodiversity of soil invertebrates that may be useful as reference for such monitoring and for field studies on chemical side effects.