Non-invasive genetics is a powerful tool in wildlife research and monitoring, especially when dealing with elusive\ud and rare species such as the Eurasian otter (Lutra lutra). Nevertheless, otter DNA obtained from scats and anal secretions\ud appears to be exposed to very quick degradation processes, and the success rate in DNA amplification is lower\ud than in other carnivores.We collected 191 samples from April to September 2011 along the river Sangro basin (Italy) which was recently re-colonized by the Eurasian otter. Using two sets of microsatellite loci (six Lut and seven OT loci), we investigated the influence of sample type and age, collection time, storage time, temperature and humidity on genotyping success and amplification success. We also tested the efficacy of different DNA extraction kits and storage buffer mediums. Finally, we compared amplification success rate, allelic dropout and false allele rates for each locus. We obtained a mean amplification success rate of 79.0% and a genotyping success rate of 35.1 %. Fresh pure jellies yielded the highest amplification success and genotyping rate. Six microsatellite loci should be theoretically sufficient to istinguish the individual unrelated otters (PID=0.001), while 13 loci were needed to distinguish sibling otters (PIDsibs=0.002) in our population. We identified 11 otters, and molecular sexing ascertained the presence of five males, four females and two uncertain individuals. Generalized linear models highlighted a significant influence of sample type and age, temperature and humidity both on genotyping and amplification success

Camera-trapping represents a powerful tool in wildlife research, particularly when dealing with\ud elusive and rare species such as otters (Lutra spp.). Nevertheless, detection problems arise when trying to\ud detect otters with camera traps. We hypothesized that the temperature difference between the otter emerging\ud from the water and the environment was too low to be detected by the standard passive infrared sensors\ud (PIR). During June–September of 2010 and 2011 in the Sangro River basin in central Italy, we designed and\ud tested a new pressure trigger and compared its effectiveness with that of the standard PIR. Results are\ud encouraging and suggest that the new trigger could be able to detect otters and other semi-aquatic mammals

The Eurasian otter is endangered in Italy, only surviving in southern river basins. The spatial and social structure of a population living at the border of the current range was explored through a noninvasive genetic study along 174 km of the Sangro river. Sampling was conducted in 2011 and 2012, collecting spraints and anal jellies at 62 marking sites. Samples were successfully genotyped at 13 nuclear microsatellites and the ZFX/ZFY locus for molecular sexing, resulting in 14 distinct genotypes (4 females, 2 possible females, 8 males), from 35 marking sites. Mean captures/recaptures rate was 3.8 captures/individual, with males being recaptured more frequently than females. Spatial overlap among individuals was analyzed through a linear regression model fitted against sibship categories and sex pairing. Nine out of the fourteen genotyped individuals belonged to three full-sib clusters, while five individuals had no full-sibs in the population. Full-sibs overlapped more than half-sibs, while male–male pairs showed significantly higher spatial overlap than both male–female and female–female pairs. Estimated mean density was 0.152 otters/km and 2.4 individuals/10 × 10 km grid cell. Accordingly, the 3440 grid cells of otter occurrence in Italy could likely host about 8000 otters, suggesting the current population has become larger than the minimum viable population size.