Molecular methods in nature conservation

Molekulare Methoden spielen in der Ornithologie eine zunehmend wichtigere Rolle. Während bisher vor allem systematische Fragen und Vaterschaftsanalysen im Fokus standen, steht heute häufig die Anwendung genetischer Methoden im angewandten Naturschutz im Mittelpunkt. Dazu wurde innerhalb der letzten Jahre eine Reihe von Verfahren entwickelt, die es erlauben nicht nur aus Blutproben, sondern auch aus Materialien wie Mauserfedern, Kotproben oder auch Eischalen genetisches Material zu gewinnen. Damit ist es möglich auch von bedrohten und scheuen Arten ohne direkten Fang Informationen zu erhalten, die für den Schutz der Art relevant sind. So lassen sich Populationen identifizieren die eines besonderen Schutzstatus bedürfen oder erkennen, ob Populationen miteinander im Austausch stehen oder bereits voneinander isoliert sind. Damit lassen sich dann konkrete Managementpläne erstellen.Molecular tools are getting more and more important in the conservation of species. I here present an overview of source materials that can be used to obtain genetic material in bird studies. I further demonstrate how genetic studies can help us to address key questions in conservation. Using grouse as a model species I show how conservation units can be identified and that genetic tools can help us to infer barriers to dispersal. Identifying gene flow among areas and monitoring the number of individuals gives us the necessary knowledge to create the best corridors and develop specific management and action plans

Isolation and characterisation of 17 microsatellite loci for the red-billed chough (Pyrrhocorax pyrrhocorax)

Peer reviewedPostprin

On the relative importance of ecology and geographic isolation as drivers for differentiation of call types of red crossbillLoxia curvirostrain the Palearctic

Efforts to understand the process of speciation have been central to the research of biologists since the origin of evolutionary biology as a discipline. While it is well established that geographic isolation has played a key role in many speciation events, particularly in birds, there is ongoing debate about how frequent speciation is in the partial or complete absence of geographical isolation. In the red crossbill Loxia curvirostra, good arguments do exist for sympatric speciation processes. In this species, several classes of calls are clustered in distinct groups, so‐called ‘call types', which mate assortatively. Often, several call types can be found at a single site, breeding and feeding next to each other. It has been hypothesized that red crossbill call types evolved by specialising in extracting seeds from cones of different conifer species. Alternatively, call types might have evolved in temporal geographic isolation. Within Europe, little is known about the distribution of the various call types and preferences for distinct food resources. In this study, we analysed the temporal and spatial occurrence of red crossbill call types in the Palearctic, investigated potential reasons for call‐type composition at a site, and compared the occurrence of call types with the fructification of conifers. Call‐type composition changed with site and season but hardly with conifer species. With our data, we could localise range areas of twelve different call types, which cannot be explained by conifer species occurrence. Therefore, we suggest that call types evolved in parapatry in most of the northern Palearctic region, and, although contradictory results exist from Iberia, we argue that differentiation might be driven by the same drivers there as well. Additionally, we discuss the potential influence of anthropogenic changes of forest composition and distribution on call types, which offers a unique possibility for future studies

Pronounced genetic structure and low genetic diversity in European red-billed chough (Pyrrhocorax pyrrhocorax) populations

Conservation Genetics August 2015, Volume 16, Issue 4, pp 1011–1012 Erratum to: Pronounced genetic structure and low genetic diversity in European red-billed chough (Pyrrhocorax pyrrhocorax) populations Erratum to: Conserv Genet (2012) 13:1213–1230 DOI 10.1007/s10592-012-0366-6 In the original publication, Tables 3 and 6 were published with incorrect estimates of population heterozygosities. All other diversity statistics were correct as originally presented. Updated versions of Tables 3 and 6 with corrected heterozygosity estimates confirmed using Arlequin 3.5 (Excoffier and Lischer 2010) as in Dávila et al. (2014) are provided in this erratum. Discrepancies were minor for populations on the British Isles. The correct estimates for Spain are slightly larger than those reported for La Palma by Dávila et al. (2014), but this does not necessarily affect their interpretation that choughs on La Palma may have originated from multiple migration events. The original conclusion that chough populations on the British Isles have low genetic diversity compared to continental European populations remains and is now, in fact, strengthened.Peer reviewedPostprin

Saproxylic beetles respond to habitat variables at different spatial scales depending on variable type and species’ mobility: the need for multi-scale forest structure management

The response of species to the environment is scale-dependent and the spatial scale at which this relationships are measured may affect conservation recommendations. Saproxylic beetles depend on decaying- and deadwood which occur in lower quantities in managed compared to natural forests. Most studies have investigated the habitat selection of saproxylic beetles at the stand scale, however depending on the species mobility, the amounts and distribution of forest attributes across the landscape may be equally important, and thus crucial to frame quantitative conservation targets. To address this gap, we evaluated the influence of environmental variables, derived from remote sensing across multiple spatial scales (50, 100, 250, 500 and 1000 m radius), on saproxylic beetles habitat selection. Focusing on four mobile and four flightless species, we hypothesized that mobile species respond to habitat variables at broader scales compared to flightless species, and that variables describing forest structure explain species presence better at smaller scales than variables describing other landscape features. Forest structure variables explained around 40% of the habitat selection, followed by variables describing forest type, topography and climate. Contrary to our expectations, mobile species responded to variables at smaller scales than flightless species. Saproxylic beetle species therefore respond to the availability of habitat features at spatial scales that are inversely related to their dispersal capacities, suggesting that less mobile species require larger areas with suitable habitat characteristics while mobile species can also make use of small, distributed patches with locally concentrated habitat features

Genetic variability in European black grouse (Tetrao tetrix)

We studied microsatellite genetic variation in 14 different geographic populations of black grouse (Tetrao tetrix) across the European range. Populations were grouped in three different fragmentation categories: isolated, contiguous and continuous, respectively. Genetic diversity, measured as observed heterozygosity (H O), expected heterozygosity (H E) and allelic richness, were lower in isolated populations as compared to the other two categories that did not differ amongst one another. These results imply that lowered genetic variability in black grouse populations is negatively affected by population isolation. Our results suggest that the connectivity of small and isolated populations in Western Europe should be improved or else these face an increased risk of extinction due to genetic and demographic stochasticity

The evolutionary history and genomics of European blackcap migration

Seasonal migration is a taxonomically widespread behaviour that integrates across many traits. The European blackcap exhibits enormous variation in migration and is renowned for research on its evolution and genetic basis. We assembled a reference genome for blackcaps and obtained whole genome resequencing data from individuals across its breeding range. Analyses of population structure and demography suggested divergence began ~30,000 ya, with evidence for one admixture event between migrant and resident continent birds ~5000 ya. The propensity to migrate, orientation and distance of migration all map to a small number of genomic regions that do not overlap with results from other species, suggesting that there are multiple ways to generate variation in migration. Strongly associated single nucleotide polymorphisms (SNPs) were located in regulatory regions of candidate genes that may serve as major regulators of the migratory syndrome. Evidence for selection on shared variation was documented, providing a mechanism by which rapid changes may evolve

'Intentional genetic manipulation' as a conservation threat

Wildlife ranching including the hunting, collection, sales and husbandry of wild animals in captivity, is practised worldwide and is advocated as an approach towards the conservation of wild species. While many authors have explored the biological impacts of intensive wild population management, primarily with respect to disease transmission (especially in ungulates and fish), the evolutionary and demographic effects of wildlife ranching have been examined less intensively. We discuss this issue through the case of intensive wildlife management in southern Africa. The genetic consequences of this global practice, with an emphasis on Africa, were addressed by a motion passed at the 2016 IUCN World Congress- ‘Management and regulation of intensive breeding and genetic manipulation of large mammals for commercial purposes’. Here, we highlight concerns regarding intensive breeding programs used to discover, enhance and propagate unusual physical traits, hereafter referred to as ‘Intentional Genetic Manipulation’. We highlight how ‘Intentional Genetic Manipulation’ potentially threatens the viability of native species and ecosystems, via genetic erosion, inbreeding, hybridisation and unregulated translocation. Finally, we discuss the need for better policies in southern Africa and globally, regarding ‘Intentional Genetic Manipulation’, and the identification of key knowledge gaps

Gauging DNA degradation among common insect trap preservatives

Genetic methods for species identification are becoming increasingly popular and can accelerate insect monitoring. However, obtaining good DNA quality and quantity from insect traps remains a challenge for field studies. Ethylene glycol, propylene glycol, and Renner solution have been previously suggested as suitable preservatives for the collection of genetic material, but a systematic overview of their performance under compromising field conditions is lacking. Here we experimentally test whether and how different preservatives affect DNA quality under different conditions and evaluate how choice of preservative may affect metabarcoding and more demanding downstream applications (e.g., RADseq). For this, we used the house cricket, Acheta domesticus (L.) (Orthoptera: Gryllidae), and tested propylene glycol, ethylene glycol, and Renner solution for their ability to preserve DNA over 27 days in various dilutions and temperatures. DNA quality was measured as DNA fragmentation and success rates in PCR amplifying a COI fragment of 658, 313, or 157 bp. Undiluted propylene glycol and ethylene glycol always retained high molecular weight DNA at room temperature. No high molecular weight DNA was preserved at 37 °C or in any dilution. Nevertheless, the COI sequence could be amplified from samples at every condition. Renner solution did not preserve high molecular weight DNA and fragmentation increased over time at 37 °C until amplification was impossible. The results suggest that propylene glycol and ethylene glycol are suitable preservatives for collecting both genetic and morphological material, but dilution or high temperatures compromise their ability to preserve high molecular weight DNA. For genomic approaches requiring high DNA quality, additional preservatives may need to be tested

The evolutionary history and genomics of European blackcap migration

Seasonal migration is a taxonomically widespread behaviour that integrates across many traits. The European blackcap exhibits enormous variation in migration and is renowned for research on its evolution and genetic basis. We assembled a reference genome for blackcaps and obtained whole genome resequencing data from individuals across its breeding range. Analyses of population structure and demography suggested divergence began ~30,000 ya, with evidence for one admixture event between migrant and resident continent birds ~5000 ya. The propensity to migrate, orientation and distance of migration all map to a small number of genomic regions that do not overlap with results from other species, suggesting that there are multiple ways to generate variation in migration. Strongly associated single nucleotide polymorphisms (SNPs) were located in regulatory regions of candidate genes that may serve as major regulators of the migratory syndrome. Evidence for selection on shared variation was documented, providing a mechanism by which rapid changes may evolve