Direct effects of the insecticide deltamethrin on zooplankton and benthic invertebrates werestudied during an attempt to eradicate signal crayfish. In accordance with earlier studies theresults of this investigation showed that deltamethrin is highly toxic for arthropods, whileRotifera, Oligochaeta and Mollusca have a higher tolerance. This study concludes thatRotifera in treated ponds coped with the actual concentration of deltamethrin used during theeradication attempt but that they probably got a different abundance and changed compositiondue to a new situation in competition and predation. Crustacean zooplankton totallydisappeared, but approximately a month after the treatment they began to recolonise. All thetaxonomical groups of arthropods drastically decreased in abundance, with total eliminationof the most sensitive groups.

Game fields are one way to divert animals away from sensitive areas, create shelter and forage, and also to increase the biological diversity. In this study I investigated how the plant composition in six different crop mixes used for game fields affected the biomass production, biomass consumption and biological diversity at the Koberg estate in southwestern Sweden. Six experimental fields were used and each field contained six plots, approximately 1500 m2 each, that was sown with a different crop mix. The crop mixes ranged from a pure grass mix (A), 70 % grass and 30 % leguminous plants (B), 53 % grass, 21 % leguminous plants and 26 % other herbs (C), 100 % leguminous plants (D) to the most complex mixes constituting of 91 % leguminous plants and 9 % other herbs (E) and 87 % leguminous plants and 13 % other herbs (F). The fields were cut weekly during the summer in 2010, to estimate weekly biomass production.