The genomes of Darwin's primroses reveal chromosome-scale adaptive introgression and differential permeability of species boundaries

Introgression is an important source of genetic variation that can determine species adaptation to environmental conditions. Yet, definitive evidence of the genomic and adaptive implications of introgression in nature remains scarce. The widespread hybrid zones of Darwin's primroses (Primula elatior, Primula veris, and Primula vulgaris) provide a unique natural laboratory for studying introgression in flowering plants and the varying permeability of species boundaries. Through analysis of 650 genomes, we provide evidence of an introgressed genomic region likely to confer adaptive advantage in conditions of soil toxicity. We also document unequivocal evidence of chloroplast introgression, an important precursor to species-wide chloroplast capture. Finally, we provide the first evidence that the S-locus supergene, which controls heterostyly in primroses, does not introgress in this clade. Our results contribute novel insights into the adaptive role of introgression and demonstrate the importance of extensive genomic and geographical sampling for illuminating the complex nature of species boundaries

Whole-genome analyses disentangle reticulate evolution of primroses in a biodiversity hotspot

Biodiversity hotspots, such as the Caucasus mountains, provide unprecedented opportunities for understanding the evolutionary processes that shape species diversity and richness. Therefore, we investigated the evolution of Primula sect. Primula, a clade with a high degree of endemism in the Caucasus. We performed phylogenetic and network analyses of whole-genome resequencing data from the entire nuclear genome, the entire chloroplast genome, and the entire heterostyly supergene. The different characteristics of the genomic partitions and the resulting phylogenetic incongruences enabled us to disentangle evolutionary histories resulting from tokogenetic vs cladogenetic processes. We provide the first phylogeny inferred from the heterostyly supergene that includes all species of Primula sect. Primula. Our results identified recurrent admixture at deep nodes between lineages in the Caucasus as the cause of non-monophyly in Primula. Biogeographic analyses support the 'out-of-the-Caucasus' hypothesis, emphasizing the importance of this hotspot as a cradle for biodiversity. Our findings provide novel insights into causal processes of phylogenetic discordance, demonstrating that genome-wide analyses from partitions with contrasting genetic characteristics and broad geographic sampling are crucial for disentangling the diversification of species-rich clades in biodiversity hotspots

Rasengesellschaften im Kontaktbereich der Karpatischen und Pannonischen Region : ein Beispiel aus dem Berggebiet Muránska Planina (mittlere Slowakei)

Muránska planina Mts, a small karstic area situated in the southern part of the Western Carpathians in Central Slovakia was chosen as a model region for the study of the variability and diversity patterns of thermophilous and mountain non-forest vegetation on the crossing of the Carpathian and Pannonian bioregions. Altogether, 113 new relevés were sampled using standard methods of the Zürich-Montpellier approach and compared with previously published data. The dataset containing both new and published phytosociological relevés from dry, semi-dry and mesic grasslands (265 relevés) was analysed using the program JUICE 7.0.98. The Beta flexible method, relative Sorensen distance as a similarity measure, and logarithmic transformation of species covers were used for the numerical classification (PC-ORD). The main environmental gradients of species composition were analysed by DCA in the CANOCO 4.5 package using the Borhidi indicator values. The various mosaics of plant communities were detected in succession series from pioneer rocky stands through open rocky grasslands dominated by Festuca pallens, F. tatrae, Carex humilis and Sesleria albicans to closed tall grass communities dominated by Calamagrostis varia and C. arundinacea. Plant communities belonging to six classes (Sedo-Scleranthetea, Festuco-Brometea, Elyno-Seslerietea, Thlaspietea rotundifolii, Mulgedio-Aconitetea and Molinio-Arrhenatheretea) including Pannonian grasslands of the alliance Bromo pannonici-Festucion pallentis and high montane/subalpine grasslands of the alliance Astero alpini-Seslerion calcariae occur together in the study area. High floristic richness and extraordinary diffusion of thermophilous and montane/subalpine elements is characteristic for the majority of the studied plant communities.Einleitung: Auf dem Gebiet der Slowakei treten zwei biogeographische Regionen miteinander in Kontakt, die Karpatische und die Pannonische Region. Das Berggebiet Muránska Planina am Südrand der Westkarpaten wurde als Modellregion gewählt, um die Variabilität und Diversität der thermophilen und montanen waldfreien Vegetation in dieser Grenzsituation zu studieren. Muránska Planina ist ein kleines Karstgebiet mit einer Fläche von etwa 40 km² und Seehöhen zwischen 400 und 1400 m ü.d.M. (Abb. 1). Aufgrund seiner biogeographischen Position, der vielfältigen geologischen und geomorphologischen Bedingungen und einer außergewöhnlichen Vielfalt an Standorten ist das Gebiet von hohem Naturschutzwert. Material und Methoden: Insgesamt wurden 113 neue Vegetationsaufnahmen angefertigt und mit älteren Daten aus der Slowakischen Vegetationsdatenbank verglichen. Der Datensatz aus neuen und älteren Aufnahmen von Trockenrasen, Halbtrockenrasen und Frischwiesen (265 Aufnahmen) wurde mit Hilfe des Programms JUICE 7.0.98 ausgewertet. Für die numerische Klassifikation wurde die „Beta flexible“-Methode mit relativer Sorensen-Distanz und logarithmischer Transformation der Deckungswerte gewählt. Zur standörtlichen Erklärung der floristischen Gradienten wurde eine DCA mit CANOCO 4.5 gerechnet, wobei die Seehöhe und mittlere Borhidi-Zeigerwerte als passive Umweltvari-ablen verwendet wurden. Ergebnisse: Es wurden insgesamt zwölf Gesellschaften, welche zu sechs Klassen gehören, identifiziert (Beilage S1–S3, Tab. 1). Die DCA zeigte eine klare Differenzierung der Rasentypen entlang der standörtlichen Gradienten (Abb. 2 und 3). Der Vergleich von Seehöhen und mittleren Borhidi-Zeigerwerten ergab einige signifikante Unterschiede zwischen den Gesellschaften (Abb. 4). Folgende Gesellschaften wurden durch eigene Aufnahmen dokumentiert und sind im Text näher beschrieben: Sedo-Scleranthetea: Jovibarbo-Sedetum albi (offene thermophile Pionierfluren); Festuco-Brometea: Campanulo divergentiformis-Festucetum pallentis (offene thermophile Felstrockenrasen), Orthantho luteae-Caricetum humilis (Trockenrasen über etwas tiefergründigen Böden); Elyno-Seslerietea: Pulsatillo slavicae-Caricetum humilis (montane Carex humilis-Rasen mit einer Mischung aus thermophilen und subalpinen Elementen), Minuartio langii-Festucetum pallentis (offene montane Felstrockenrasen); Thlaspietea rotundifolii: Vincetoxicum hirundinaria-Gesellschaft (Schuttfluren); Mulgedio-Aconitetea: Convallario majalis-Calamagrostietum variae (Hochgrasfluren auf gut wasserversorgten, steilen Schutthängen). Diskussion: Die verschiedenen Gesellschaften sind oft mosaikartig entlang von Standortsgradienten angeordnet, welche von Pionierfluren über lückige Felstrockenrasen mit den dominanten Arten Festuca pallens, F. tatrae, Carex humilis und Sesleria albicans bis zu geschlossenen Hochgrasfluren mit Calamagrostis varia und C. arundinacea reichen. Pannonische Trockenrasen des Verbands Bromo pannonici-Festucion pallentis und hochmontan-subalpine Rasen des Verbands Astero alpini-Seslerion calcariae finden sich im Untersuchungsgebiets oft in enger Nachbarschaft. Für die Mehrzahl der untersuchten Gesellschaften ist ein großer Artenreichtum und eine Durchmischung von thermophilen pannonischen und montan-subalpinen karpatischen Elementen charakteristisch. Zu den häufigsten Vegetationstypen im Gebiet zählen Pionierfluren (Jovibarbo-Sedetum albi) sowie Trockenrasen, welche floristisch zwischen den Klassen Festuco-Brometea und Elyno-Seslerietea vermitteln, wie Orthantho luteae-Caricetum humilis und Pulsatillo slavicae-Caricetum humilis

Native and Alien Plant Species Richness Response to Soil Nitrogen and Phosphorus in Temperate Floodplain and Swamp Forests

Soil nitrogen and phosphorus are commonly limiting elements affecting plant species richness in temperate zones. Our species richness-ecological study was performed in alder-dominated forests representing temperate floodplains (streamside alder forests of Alnion incanae alliance) and swamp forests (alder carrs of Alnion glutinosae alliance) in the Western Carpathians. Species richness (i.e., the number of vascular plants in a vegetation plot) was analyzed separately for native and alien vascular plants in 240 vegetation plots across the study area covering Slovakia, northern Hungary and southern Poland. The relationship between the species richness of each plant group and total soil nitrogen content, plant-available phosphorus and carbon to nitrogen (C/N) ratio was analyzed by generalized linear mixed models (GLMM) with Poisson error distribution and log-link function. The number of recorded native and alien species was 17–84 (average 45.4) and 0–9 (average 1.5) species per plot, respectively. The GLMMs were statistically significant (p ˂ 0.001) for both plant groups, but the total explained variation was higher for native (14%) than alien plants (9%). The richness of native species was negatively affected by the total soil nitrogen content and plant-available phosphorus, whereas the C/N ratio showed a positive impact. The alien richness was predicted only by the total soil nitrogen content showing a negative effect

Environmental drivers of macrophyte species richness in artificial and natural aquatic water bodies – comparative approach from two central European regions

Species richness of macrophytes of artificial and natural water bodies covering rivers, streams, canals and habitats with standing water was studied in two Central European biogeographical regions, Pannonian and Carpathian, represented by two model areas (the Borská nížina Lowland and the Turčianska Kotlina Basin). We found that: (i) the total number of macrophytes was higher in artificial water bodies compared to natural aquatic habitats in both regions and differences were statistically significant (P<0.05); and (ii) species richness of macrophytes is relatively low in both regions; slightly higher mean number was found in the Pannonian region (3.53) compared with the Carpathian region (3.06). Effects of environmental characteristics on species richness studied by generalized linear model (GLM) showed that explained variances of GLM were similar in both regions. The main drivers of the diversity pattern were those connected with the hydrology of water bodies, such as substrate characteristics and turbidity, less frequent were chemical characteristics, such as water conductivity and N-contents, whereas landscape characteristics manifested the smallest impact.Macrophyte richness of artificial and natural water bodies covering rivers, streams, canals and habitats with standing water was studied in Pannonian and Carpathian regions (Central Europe). Total number of macrophytes was significantly (P<0.05) higher in artificial water bodies compared to natural aquatic habitats in both regions. Hydrological variables followed by chemical and landscape factors were identified by generalised linear model (GLM) as the underlying sources of variation in macrophyte species richness

Comparative diversity of vascular plants in black alder floodplain and swamp forests of Central European biogeographical regions

Plant species diversity of black alder-dominated forests was studied in three biogeographical regions (Alpine, Continental and Pannonian) of Central Europe. They were represented by regions of the Polish Plain (Continental), the High Western Carpathians and Matricum of the Western Carpathians (Alpine) and the Pannonian lowland (Pannonian). We analysed 35 plots per region in order to identify: i) local alpha (α) diversity defined as the counted number of plant taxa occurring in a single sampling plot, ii) amongst-site beta (β) diversity, iii) regional (γ) diversity defined as the total species richness of all sampling plots and iv) zeta diversity (ζ) as a generalisation of beta diversity. We recorded a total of 432 vascular plant taxa in all bioregions; more than 13% were alien plants. Statistically significant differences in species richness (α) of both native and alien plants were found between assemblages of the regions. The High Western Carpathians showed the highest native and the lowest alien plant species richness. Total β-diversity was high in all regions, but significantly differed amongst regions only for alien plant species. Cumulative native and alien species richness (γ) was the highest and lowest in the High Western Carpathians and Matricum of Western Carpathians, respectively. Our results identified the High Western Carpathians as a hotspot for diversity of native plants in Central European black alder-dominated forests