EFFECTS OF MOLLUSCICIDES ON SEEDLINGS OF 4 GRASSLAND PLANT-SPECIES

1. We tested the hypothesis that molluscicides may affect seedling ger mination and survival, as well as reducing herbivory, thereby influenc ing the results of experiments in which molluscicides are used to excl ude molluscs from plant communities. 2. The effects of two molluscicid es, Fertosan and Draza, on seed germination of four common grassland h erbs, Plantago lanceolata, Ranunculus acris, Senecio jacobaea and Tara xacum officinale, were examined over a 100-day study. 3. Draza slug pe llets reduced seedling numbers in Plantago, while increasing numbers o f Ranunculus seedlings. The molluscicides, either separately or togeth er, had no effect on numbers of Senecio or Taraxacum. 4. The implicati ons of the results are discussed in relation to the interpretation of field experiments where molluscicides are used as experimental tools. We also raise the question of how molluscicides may influence field po pulations of native weed species in agricultural systems.