Institut für ökologische Chemie, Pflanzenanalytik und Vorratsschutz
The occurrence of small aquatic habitats, i.e. kettle holes, can be seen as elements of high functional importance in agroecosystems that additional acta s sinks for agricultural contaminants. Aquatic insects, which are bound to the aquatic environment as juveniles but later in their life history leave the kettle holes, serve as mobile links of these critical contaminants as they are considered as an important food resource for riparian predators. Water samples, emerging insects, riparian predators (spiders, carabis beetles) and feces of birds and bats will be analysed for pesticide residues to exemplarily demonstrate fluxes of pesticides via emerging water insects in agricultural landscapes.Emergence traps are set up at 10 wells of different sizes to collect emergent insects. In addition, water samples are taken for each collection of emergent insects. For the sampling of emergent insects, three sampling campaigns will be carried out on three consecutive days, each three weeks apart,ng in mid-April/early May 2022. Sampling of riparian predators (one campaign) will take place in late spring/early summer 2022. The water samples taken during each sampling campaign will be analyzed for 121 pesticide active substances and the results evaluated with regard to substance contamination and possible toxic effects on standard test organisms. Spiders (e.g. Araneidae, Tetragnathidae, Linyphiidae and Lycosoidae) are typical riparian predators that feed on aquatic insects. In a study on wolf spiders, Fritz et al. (2017) found higher immunocompetence in individuals inhabiting wetlands compared to those living in landscapes without water. Similar to spiders, ground beetles also feed on emergent insects and are found in high densities around marshes. It is known that swallows depend on emergent insects for their reproductive success. The movement patterns and foraging behavior of house martins and barn swallows will be tracked in relation to the emergence patterns of different wetlands. In addition, foraging behavior and pesticide contamination of swallow droppings are correlated with reproductive success, i.e. the number of eggs laid and fledged young. Bats are important aquatic predators and some species are dependent on aquatic insects. The movement patterns of the common noctule are compared with the pesticide load of the droppings.
Federal Ministry of Food and Agriculture
