Assessing the toxicity of pesticides towards soil invertebrates

Background

Soil invertebrates perform an important role in ecosystems, for example by recycling the organic matter. However, the services provided by these organisms are at risk because of the widespread use of pesticides, like the neonicotinoid insecticides. These pesticides already at low doses may cause high mortality rates among target and non-target organisms. Some of the consequences are the reduction of local biodiversity and the loss of ecosystem services. Recent studies also show that agricultural soils may contain mixtures of pesticide residues. Only limited data is available on the toxicity of pesticides and their mixtures to soil invertebrates, and on the possible consequences for ecosystem services.

Earlier research of our group has shown that the widely used parthenogenetic springtail species Folsomia candida is quite sensitive to neonicotinoids, and also that other springtail species show similar sensitivity. And we also found that soils from conventional agricultural containing pesticide residues were toxic to different soil invertebrate species.

Several questions remain however, to be answered, like for instance:

  1. How do effects at the individual level translate to the performance of springtails in a community, and can a trait-based approach be used make this translation?
  2. How toxic are field soils containing a mixture of pesticides to soil invertebrates?

Approaches

  1. The toxicity of selected pesticides to different species of springtails will be determined in single-species tests and in multispecies tests with more realistic exposure scenarios. The relation between response and effect traits will be investigated to link effects of these pesticides to impacts on ecosystem services.
  2. The effects of pesticides will be studied under realistic exposure scenarios, involving several applications in a season and of mixtures of pesticides. Single species tests as well as soil mesocosm tests containing intact communities will be performed. Effects of the pesticides will be determined on the reproduction and survival of the test organisms, but also on their role in decomposition and other processes (ecosystem services). The final aim is to determine to what extent soil communities may be affected by pesticides.
  3. The toxicity of field soils collected from areas with different intensity of pesticide use will be tested using a battery of soil invertebrate tests (earthworms, enchytraeids, springtails, etc.). Effects on survival, growth and reproduction related to the presence of the mixture of different pesticides detected in the test soils will be assessed.

What you can learn?

You will be taught how to identify useful literature, and you will gain experience with methods for culturing, toxicity testing of soil organisms, the design of (complex) experiments, modelling and statistical analysis of ecotoxicity data, etc. You will write a scientific report at the end of this internship, with the possibility of contributing to a publication in a peer-reviewed scientific journal.

Supervision and information

Prof.dr. C.A.M. (Kees) van Gestel
Room H150, W&N building, VU Amsterdam
E-mail: kees.van.gestel@vu.nl
Phone: +31 (0)20 – 59 87079

S.S. (Saúl) Monteiro Fernandes MSc
Room H127, W&N building, VU Amsterdam
E-mail: s.s.monteirofernandes@vu.nl