To substantiate the pathways of radiocaesium contamination in wild boars in parts of RhinelandPalatinate, we analysed radiocaesium-activityconcentration of 2,433 wild boars shot in an area covering 45,400 ha in the western part of the Palatinate Forest between January 2001 and February 2003. Also, for a fraction of 689 animals shot between May 2002 and February 2003, we collected their stomachs for the examination of content and Cs-activity concentration. Wild boar meat contamination followed a seasonal curve with maximum proportions exceeding accepted levels in the summer (21-26%) and minimum levels in winter (1-9.3%) indicating a higher consumption of a contaminating source during the vegetation period. The autumn decline is obviously attributed to the extensive consumption of low-contaminated beech nuts. An exact analysis of food composition in 18 stomachs with maximum Cs-activity concentrations [345-1,749 Bq/kg (fresh matter: fm)] and 18 with low Cs-activity concentrations ( £ 20-199 Bq/kg) was carried out in the summer of 2002. Deer truffles (Elaphomyces granulatus) were found in significantly higher proportions in stomachs with maximum contamination levels than in stomachs with lowcontamination levels. This fungus was found in the Palatinate Forest, by a trained dog, in average densities of 1 truffel/20 m 2 primarily in spruce stands, showing an average Cs-concentration of 6,030 Bq/kg (fm). On the basis of our findings we stress the hypothesis that deer truffles function as a main Cssource for the wild boar in Rhineland-Palatinate.
Reliable estimation of population size remains a major challenge in wildlife ecology and management. Lately, genotyping of non-invasively obtained tissue samples integrated in a modified capture-recapture approach provides new perspectives. Faeces, moulted feathers, or hairs can be easily sampled in the field. However, an important assumption is homogeneity of sampling across the population. In this pilot study, we tested the suitability of baited barbed wire hair sampling stations ('hair traps') for homogeneous genetic sampling for population estimation. A video system based on a new network internet protocol was used to observe the behaviour of wild boar visiting baited hair traps for gaining information about potential heterogeneities in the individual sampling probability. Within 92 monitoring nights at two sampling stations, 216 wild boar visits were recorded and 142 hair samples containing 2,124 single hairs were collected. Video analysis revealed distinct differences in the behaviour of wild boar with respect to the sampling station which are most likely to result in heterogeneous individual sampling probabilities. Adult and subadult animals differed in their behaviour dependent on their group status. This result indicates that hair sampling with baited hair traps is not suitable for representative non-invasive sampling of free ranging wild boar populations.
A digital infrared video camera system was developed for recording and remote capturing. The components are described in detail. Based on 2 years of experience within a wild boar (Sus scrofa) project, the system gave proof of its practicability, reliability and efficiency.
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