Untersuchungen zu Verhaltensänderungen bei Igeln (Erinaceus europeus L.) durch Aufnahme des Molluskizids Metaldehyd

Studies on Behavioural thanges in Hedgehogs (Erinaceus europaeus L) Through Uptake of the Molluscicide Metaldehyde Plant protection products may cause harm for non-target organisms even in sublethal doses. This leads to an injury of individuals or in fact to the decrease of a whole population. This paper aims in developing a method to measure the quantity of the change in hedgehogs' behaviour. These changes are caused by sublethal doses of the molluscicide metaldehyde. It should be proved which of the examined behaviour is modified and which doses of metaldehyde lead to such modifications. It is tested whether the statistical analysis can be used for repeated measurement which decreased the number of examined individuals. Furthermore it is of interest whether the respective doses can be reached outdoors by a hedgehog. In the Federal Biological Research (entre for Agriculture and Forestry in Münster (Germany) 21 hedgehogs where examined in Open-Field and walking gait experiments. Using discriminant analysis, analysis of variance (ANOVA, MANOVA), and probit analysis one could prove that a dose of about 70 mg metaldehyde per kilogram body mass leads to a decrease of the locomotory activity for half of the number of individuals on average. By the use of repeated measurement the number of examined individuals could be decreased very much. Feeding experiments proved additionally that the quantity of metaldehyde is reachable for hedgehogs outdoors. By ingestion of whole slug baits together with the besides lying slug hedgehogs can take in enough poison in short time and in a small area (about 4 m2) to show symptoms of poisoning in their behaviour.