Admixture between genetically divergent populations facilitates genomic studies of the mechanisms involved in adaptation, reproductive isolation, and speciation, including mapping of the loci involved in these phenomena. Little is known about how pre-and postzygotic barriers will affect the prospects of ''admixture mapping'' in wild species. We have studied 93 mapped genetic markers (microsatellites, indels, and sequence polymorphisms, $60,000 data points) to address this topic in hybrid zones of Populus alba and P. tremula, two widespread, ecologically important forest trees. Using genotype and linkage information and recently developed analytical tools we show that (1) reproductive isolation between these species is much stronger than previously assumed but this cannot prevent the introgression of neutral or advantageous alleles, (2) unexpected genotypic gaps exist between recombinant hybrids and their parental taxa, (3) these conspicuous genotypic patterns are due to assortative mating and strong postzygotic barriers, rather than recent population history. We discuss possible evolutionary trajectories of hybrid lineages between these species and outline strategies for admixture mapping in hybrid zones between highly divergent populations. Datasets such as this one are still rare in studies of natural hybrid zones but should soon become more common as high throughput genotyping and resequencing become feasible in nonmodel species.

The maintenance of species barriers in the face of gene flow is often thought to result from strong selection against intermediate genotypes, thereby preserving genetic differentiation. Most speciation genomic studies thus aim to identify exceptionally divergent loci between populations, but divergence will be affected by many processes other than reproductive isolation (RI) and speciation. Through genomic studies of recombinant hybrids sampled in the wild, genetic variation associated with RI can be observed in situ, because selection against incompatible genotypes will leave detectable patterns of variation in the hybrid genomes. To better understand the mechanisms directly involved in RI, we investigated three natural 'replicate' hybrid zones between two divergent Populus species via locus-specific patterns of ancestry across recombinant hybrid genomes. As expected, genomic patterns in hybrids and their parental species were consistent with the presence of underdominant selection at several genomic regions. Surprisingly, many loci displayed greatly increased between-species heterozygosity in recombinant hybrids despite striking genetic differentiation between the parental genomes, the opposite of what would be expected with selection against intermediate genotypes. Only a limited, reproducible set of genotypic combinations was present in hybrid genomes across localities. In the absence of clearly delimited 'hybrid habitats', our results suggest that complex epistatic interactions within genomes play an important role in advanced stages of RI between these ecologically divergent forest trees. This calls for more genomic studies that test for unusual patterns of genomic ancestry in hybridizing species.

SummaryStudying the divergence continuum in plants is relevant to fundamental and applied biology because of the potential to reveal functionally important genetic variation. In this context, whole-genome sequencing (WGS) provides the necessary rigour for uncovering footprints of selection.We resequenced populations of two divergent phylogeographic lineages of Populus alba (n = 48), thoroughly characterized by microsatellites (n = 317), and scanned their genomes for regions of unusually high allelic differentiation and reduced diversity using > 1.7 million single nucleotide polymorphisms (SNPs) from WGS. Results were confirmed by Sanger sequencing.On average, 9134 high-differentiation (≥ 4 standard deviations) outlier SNPs were uncovered between populations, 848 of which were shared by ≥ three replicate comparisons. Annotation revealed that 545 of these were located in 437 predicted genes. Twelve percent of differentiation outlier genome regions exhibited significantly reduced genetic diversity. Gene ontology (GO) searches were successful for 327 high-differentiation genes, and these were enriched for 63 GO terms.Our results provide a snapshot of the roles of 'hard selective sweeps' vs divergent selection of standing genetic variation in distinct postglacial recolonization lineages of P. alba. Thus, this study adds to our understanding of the mechanisms responsible for the origin of functionally relevant variation in temperate trees.

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Conservation status of hay meadows highly depends on their management. The main goal of this study was to assess the efficiency of different mowing regimes in maintenance of plant species richness and diversity of mesic hay meadows. The field experiment was carried out on a species rich, mesic hay meadow in Western Hungary. We evaluated the effects of four alternative types of management on the plant community after 7 years of continuous treatment: (1) mowing twice a year, typical traditional management, (2) mowing once a year in May, most practised currently by local farmers, (3) mowing once a year in September, often proposed for conservation management and (4) abandonment of mowing. Both cutting frequency and timing had significant effects on species richness and diversity of vegetation. Traditional mowing resulted in significantly higher number and higher diversity of vascular plant species than other mowing regimes. Mowing twice a year was the only efficient way to control the spread of the invasive Solidago gigantea, and mowing in September was more successful in it than mowing in May. We conclude that the traditional mowing regime is the most suitable to maintain botanical diversity of mesic hay meadows, however other regimes should also be considered if certain priority species are targeted by conservation.

Halting biodiversity loss is a critical aim for the forthcoming decades, but is hindered by the gap between research and practice. Bridging this gap is a significant challenge in the countries of Central and Eastern Europe, where, compared to Western European countries, biodiversity is higher but the research budget is lower. Approaches to address bridging this gap include participatory research prioritizing exercises. These demand-driven collaborative ranking processes have proven to be a useful tool in providing a research agenda derived from a review of critical challenges based on stakeholder engagement. However, for research agendas to be effectively realized, they are best developed and implemented at the operative level of research financing and implementation. This paper shows the process and the outcome of an exercise conducted in Hungary aiming to compile the most important conservation research questions at the country-level and outlines a set of further measures and tools required for dissemination and advocacy for the research agenda. During the process 792 research questions were collated from conservation practitioners and natural resource managers based on interviews and via an online questionnaire; the final 50 most important questions were identified by practitioners and policy makers during an expert workshop. Questions are embedded in global and EU biodiversity targets and imply a pragmatic approach with the aim of identifying research that supports policy-and decision-making regarding habitat management, landuse and regional development, while also focussing on conflicting issues. The outcome of the process includes the potential for lobbying, therefore post-publication activities and dissemination strategies are outlined as an integrated part of the exercise.

2018 decemberében publikálásra került az interneten Magyarország edényes növény­fa­ja­inak online elterjedési atlasza (Atlas Florae Hungariae). A több mint 1 millió adatrekord felhasználásával fel­épült adatbázis gerincét a Magyar Flóratérképezési Program során gyűjtött adatok képezik, emellett fel­dol­gozott szakirodalmi és herbáriumi adatok is elérhetők innen, illetve megjeleníthetők a térképeken. A kvad­rátok fajszám szerinti megoszlását bemutató térkép az egyes területek fajdiverzitását és a fló­ra­tér­ké­pe­zési alapfelmérés minőségi különbözőségét mutatja. Az adatbázis bővítése 2016 és 2019 között első­sor­ban szakirodalmi adatfeldolgozással folytatódott. Az így bekerült új adatok 25%-át a Kitaibelia „Pótlások” sorozata szolgáltatta, amely egyes taxonok adatainak jelentős bővülését hozta. Az adatközlések révén leg­na­gyobb mértékben az üde erdei fajok (pl. Allium ursinum, Dryopteris dilatata) adatai gyarapodtak, emellett egyes gyomnövények adatai (pl. Euphorbia maculata, Senecio vernalis) is jelentősen bővültek, amely összefüggésben áll terjedésükkel. A honlap tervezett fejlesztése során egy bővített és revideált, egy­sé­ges koncepciót követő Taxonlista megalkotása tekinthető az egyik legfontosabb feladatnak, emellett bő­ví­teni kívánjuk a térképek jelenleg alkalmazott jelkulcsrendszerét, az adatrekordokhoz kapcsolódó in­for­má­ciókat.

Abstract:In order to develop adequate adaptation measures for environmental vulnerability, we need detailed knowledge on the climatic performance of forest ecosystems. In this study, we aim to explore climate function variability of lowland beech forest distribution at a landscape scale. We also construct the response profiles of these forests near their xeric limit under wet continental climatic conditions. We studied distribution responses using presence-absence forest records and 18 bioclimatic variables. We performed exploratory factor analysis and frequency estimation to evaluate climate function distribution responses. We found that temperature adjusted precipitation measures during summer were the most important, followed by winter rainfall indices. The relative Drought Response Range (rDRR) in the response profile presented the climate limitation function of the distribution. According to our results, higher level of climate function variability is associated with lower level of rDRR, presenting an ecological trade-off. Our results suggest that distribution functions of the rDRR, especially the Ombrothermic index, can be used as landscape indicators of drought stress. Consequently, rDRR could be a useful measure to assess regional climatic vulnerability of forest occurrence and distribution patterns.