| Summary: | Kopatz, A., Kleven, O., Friebe, A., Ahlqvist, D., Kindberg, J. & Flagstad, Ø. 2021. Effects of sampling location within feces on genotyping success in brown bears. NINA Report 2022. Norwegian Institute for Nature Research. Feces samples make up the largest part of the material collected for DNA analysis in brown bear (Ursus arctos) monitoring in Norway. However, genotyping success rates vary substantially among feces samples collected during spring, summer and autumn. We studied the influence of the sampling location or spot, i.e. outside- or inside-swabbing, of brown bear fecal samples on the genotyping success using eight microsatellite markers applied in the monitoring of the spe-cies in Norway and Sweden. We also compared the results to the success rates of collecting a piece of the sample stored on silica, as is currently applied during the non-invasive genetic sam-pling to monitor brown bears in Norway. Feces were collected by tracking GPS-marked individual brown bears of the Scandinavian Brown Bear Research Project. A total of 369 samples (outside swabbing, inside swabbing and piece on silica) were collected. There was large variation in the genotyping success among all samples collected and we found no statistically significant difference between outside- (50.4%) and inside-swabbing (47.2%) of the feces. Collecting a sample from feces on silica (52.8%) provided an overall similar success rate. Genotyping success rates of all three methods showed a clear seasonal pattern with very low success rates in June and July. Outside-swabbing seemed to have the tendency to be more successful on liquid and moist feces, while pieces collected on silica seemed to provide higher success on dry feces. Estimated exposure time, the period a feces was exposed to the environment (~8 days), did not affect the condition and shape of a feces, and also did not explain the variation in genotyping success. These results suggest, that visual age estimation of scats in the field should be done with caution, as the overall state ...
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