The spatial genetic structure of common hamsters (Cricetus cricetus) was investigated using three partial mitochondrial (mt) genes and 11 nuclear microsatellite loci. All marker systems revealed significant population differentiation across Europe. Hamsters in central and western Europe belong largely to two allopatric mitochondrial lineages south and northwest of the Carpathian and Sudetes. The southern group, 'Pannonia', comprises populations inside the Carpathian basin (Czech Republic, Hungary) while the second group, 'North', includes hamsters from Belgium, the Netherlands, France, and Germany. Isolation of the lineages is maintained by a combination of geographical and ecological barriers. Both main phylogeographical groups show signs of further subdivision. North is separated into highly polymorphic central German and less polymorphic western populations, which most likely split during late glacial expansion (15,000-10,000 bp). Clock estimates based on haplotype distributions predict a divergence of the two major lineages 85,000-147,000 bp. Expansion times fall during the last glaciation (115,000-10,000 bp) corroborating fossil data, which identify Cricetus cricetus as characteristic of colder climatic phases. Despite the allopatry of mt haplotypes, there is an overlap of nuclear microsatellite alleles between phylogeographical units. Although there are strong evidence that Pannonian hamsters have persisted inside the Carpathian basin over the last 50,000 years, genetic differentiation among European hamsters has mainly been caused by immigration from different eastern refugia. Possible source populations are likely to be found in the Ukrainian and the southern Russian plains--core areas of hamster distribution. From there, hamsters have repeatedly expanded during the Quaternary.
The study described in this report was conducted with the aim of developing an unified database of ecological data and residue data to be used for the risk assessment of plant protection products for birds and mammals. The main sources of data were the information submitted in the context of approval of active substances and authorization of products and and additional information retrieved through a systematic literature review. The data were screened and organised in three Excel databases, one for birds, one for mammals and one for residue studies. The ecological information for birds and mammal risk assessment consisted of data that is used for the determination of focal species, estimation of the proportion of an animal's daily diet obtained in a treated habitat (PT) and assessment of the composition of the diet obtained from a treated area (PD). The information gathered on residues focussed on (initial) residue levels after treatment and on residue decline (the reported half‐life or DT50 and the DT90).
1.Following protection measures implemented since the 1970s, large carnivores are currently increasing in number and returning to areas from which they were absent for decades or even centuries. Monitoring programmes for these species rely extensively on non-invasive sampling and genotyping. However, attempts to connect results of such studies at larger spatial or temporal scales often suffer from the incompatibility of genetic markers implemented by researchers in different laboratories. This is particularly critical for long-distance dispersers, revealing the need for harmonized monitoring schemes that would enable the understanding of gene flow and dispersal dynamics. 2. Based on a review of genetic studies on grey wolves Canis lupus from Europe, we provide an overview of the genetic markers currently in use, and identify opportunities and hurdles for studies based on continent-scale datasets. 3. Our results highlight an urgent need for harmonization of methods to enable transnational research based on data that have already been collected, and to allow these data to be linked to material collected in the future. We suggest timely standardization of newly developed genotyping approaches, and propose that action is directed towards the establishment of shared single nucleotide polymorphism panels, next-generation sequencing of microsatellites, a common reference sample collection and an online database for data exchange. 4. Enhanced cooperation among genetic researchers dealing with large carnivores in consortia would facilitate streamlining of methods, their faster and wider adoption, and production of results at the large spatial scales that ultimately matter for the conservation of these charismatic species.
We have studied a small isolated population of black grouse (Tetrao tetrix) in the Netherlands to examine the impact of isolation and reduction in numbers on genetic diversity. We compared the genetic diversity in the last extant Dutch population with Dutch museum samples and three other black grouse populations (from England, Austria and Norway, respectively) representing isolated and continuous populations. We found significantly lower allelic richness, observed and expected heterozygosities in the present Dutch population compared to the continuous populations (Austria and Norway) and also to the historical Dutch population. However, using a bottleneck test on each population, signs of heterozygosity excess were only found in the likewise isolated English population despite that strong genetic drift was evident in the present Dutch population in comparison to the reference populations, as assessed both in pairwise F(ST)and STRUCTURE analyses. Simulating the effect of a population reduction on the Dutch population from 1948 onwards, using census data and with the Dutch museum samples as a model for the genetic diversity in the initial population, revealed that the loss in number of alleles and observed heterozygosity was according to genetic drift expectations and within the standard error range of the present Dutch population. Thus, the effect of the strong decline in the number of grouse on genetic diversity was only detectable when using a reference from the past. The lack of evidence for a population reduction in the present Dutch population by using the program bottleneck was attributed to a rapidly found new equilibrium as a consequence of a very small effective population size.
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