No abstract

The extensive use of anticoagulant rodenticides (ARs) for rodent control has led to widespread secondary exposure in nontarget predatory wildlife species. We investigated exposure rates and concentrations of five ARs in liver samples from five raptors and six owls from Denmark. A total of 430 birds were analysed. ARs were detected in 84-100 % of individual birds within each species. Multiple AR exposure was detected in 73 % of all birds. Average number of substances detected in individual birds was 2.2 with no differences between owls and raptors. Difenacoum, bromadiolone, and brodifacoum were the most prevalent substances and occurred in the highest concentrations. Second-generation ARs made up 96 % of the summed AR burden. Among the six core species (sample size >30), summed AR concentrations were lower in rough-legged buzzard (Buteo lagopus) and long-eared owl (Asio otus) than in barn owl (Tyto alba), buzzard (B. buteo), kestrel (Falco tinnunculus), and tawny owl (Strix aluco). There was a strong tendency for seasonal variations in the summed AR concentration with levels being lowest during autumn, which is probably related to an influx of less-exposed migrating birds from northern Scandinavia during autumn. High hepatic AR residue concentrations (>100 ng/g wet weight), which have been associated with symptoms of rodenticide poisoning and increased mortality, were recorded high frequencies (12.9-37.4 %) in five of the six core species. The results suggest that the present use of ARs in Denmark, at least locally, may have adverse effects on reproduction and, ultimately, population status in some raptors and owls.

Although the phylogeography of European mammals has been extensively investigated since the 1990s, many studies were limited in terms of sampling distribution, the number of molecular markers used and the analytical techniques employed, frequently leading to incomplete postglacial recolonisation scenarios. The broad-scale genetic structure of the European badger (Meles meles) is of interest as it may result from historic restriction to glacial refugia and/or recent anthropogenic impact. However, previous studies were based mostly on samples from western Europe, making it difficult to draw robust conclusions about the location of refugia, patterns of postglacial expansion and recent demography. In the present study, continent-wide sampling and analyses with multiple markers provided evidence for two glacial refugia (Iberia and southeast Europe) that contributed to the genetic variation observed in badgers in Europe today. Approximate Bayesian computation provided support for a colonisation of Scandinavia from both Iberian and southeastern refugia. In the whole of Europe, we observed a decline in genetic diversity with increasing latitude, suggesting that the reduced diversity in the peripheral populations resulted from a postglacial expansion processes. Although MSVAR v.1.3 also provided evidence for recent genetic bottlenecks in some of these peripheral populations, the simulations performed to estimate the method's power to correctly infer the past demography of our empirical populations suggested that the timing and severity of bottlenecks could not be established with certainty. We urge caution against trying to relate demographic declines inferred using MSVAR with particular historic or climatological events.

Chemical repellents are promoted as a method to reduce ungulate-vehicle collisions and ungulate browsing damages to agricultural and forestry resources. We tested the effectiveness of two odour repellents (Mota FL and Wolf Urine) on the foraging behaviour and area avoidance of free-ranging roe deer (Capreolus capreolus) and red deer (Cervus elaphus). The effects of the repellents were assessed by comparing deer visitation rates to sand arenas before and after application of repellents and visitation rates to control arenas. Neither of the tested products reduced deer visitation rates. Rapid habituation to olfactory stimuli and lack of sensitivity to predator odours may explain the ineffectiveness of the repellents to alter the behaviour of the deer. The results indicate that the tested products have no effects on roe deer and red deer behaviour and suggest that the effectiveness of the chemical area repellents as a measure to reduce deer-vehicle collision risk and browsing damages is questionable.

No abstract