Flow cytometry provides a reliable and fast method for estimating genome size and ploidy levels in plants. Until recently, most studies employed fresh tissues that usually provide high-quality results. However, the need for fresh tissues limits the use of the method with samples from remote areas or when an extremely high number of samples needs to be processed in a short time. Although there is growing evidence that fixed silica-dried material can be used for ploidy estimation in some taxa, no flora-wide study has been available so far. Here, we provide methodological aspects of an unprecedented study exploring ploidy variation of non-apomictic angiosperms in the Eastern Alps. We have analysed ~45,000 silica-dried samples of 1,134 species using flow cytometry with DAPI as stain. Surprisingly, we were able to obtain ploidy level information from as much as 1,103 (97%) of species. The unsuccessful species included succulent plants of the family Crassulaceae (genera Jovibarba, Rhodiola, Sedum, Sempervivum), the achlorophyllous parasitic or mycoheterotrophic genera Orobanche and Hypopitys, and a handful of others. About 80% of samples were successfully analysed using a single ‘universal’ protocol and leaf tissue, while in the remaining species the use of alternative tissues (such as petioles or flowers) and/or protocol modifications were needed (targeting composition of buffers, duration of incubation or staining time or use of alternative buffers). A total of 384 species (35%) included polyploid cytotypes. Among them, 151 (14%) included diploid and polyploid cytotypes, 25 species (2%) being ploidy variable with multiple polyploid cytotypes, and 208 (19%) being polyploids with just one cytotype. The remaining 719 (65%) species were diploid only. As a community resource, we provide relative genome sizes and ploidy assignments of 1,328 cytotypes retrieved from 1,103 species along with methodological details (e.g. buffers, standards, analysed plant organs, histogram quality, and other remarks). We believe that this dataset will facilitate future research in particular species as well as in flora-wide investigations of ploidy level variation of the central-European flora in general. We are confident that novel cytotypes of many species will be discovered in other geographic areas, and we would be delighted if the present dataset could serve the botanical community for comparison.
The aim of this study was to determine the current distribution of Dittrichia graveolens along motorways in Slovakia, including adjacent sections in the Czech Republic, Austria, and Hungary, to assess to what extent the density of the species depends on the age of operation of the studied motorways, and to predict the potential distribution of the species in Slovakia for the period 2021–2040. In total, 1,440 occurrence points of the species were recorded along 419.9 km of surveyed motorways (out of 826.5 km of surveyed roads). Of the 1,157 occurrence points, the highest proportion (1,065 points) was recorded in the western part of the country, with occurrence decreasing towards the east. The generalized additive mixed model showed that the occurrence density of D. graveolens was highest on older motorway sections, specifically those constructed in the late 1970s and late 1990s, while the most recently built sections (post 2012) exhibited significantly lower invasion densities. The MaxEnt model for D. graveolens under the SSP370 scenario demonstrated robust predictive performance (AUC = 0.85, TSS = 0.61). Focusing on the primary study region, the model revealed that over 24,000 km2 in Slovakia are climatically suitable for future invasion. However, given the species’ strict concentration along immediate road edges, the actual potential area of occupancy represents 32.9 km2 (0.07% of the total national area) localized within road verges. While current occurrences are heavily concentrated in the western lowlands, our predictions indicate a significant potential for continuous eastward expansion into the central and eastern regions along the road network. The primary climatic constraint is the minimum temperature of the coldest month (Bio06), which limits the species at higher altitudes. Our findings confirm that the D. graveolens invasion in Slovakia is driven by a combination of road operational age and climatic suitability. These road verges serve as critical corridors, facilitating the species’ predicted eastward expansion into new regions.
Dry grasslands on rock outcrops in deep river valleys of the Bohemian Massif are typically small and difficult to access, forming isolated open patches surrounded by forests. Although probably partly maintained by historical low-intensity land use, these habitats have often been regarded as near-natural due to their extreme environmental conditions and long-term continuity. However, it remains unclear how strongly these habitats have responded to rapidly changing environmental conditions over recent decades. In 2020–2024, we repeated vegetation sampling conducted in the 1990s (42 semipermanent plots) to analyse long-term vegetation changes in dry grasslands in the Dyje/Thaya river valley. We revealed a decline in rare and xerophilous species, the expansion of ruderal and nutrient-demanding species, and the increased cover of dwarf shrubs and tree seedlings. These changes differed between areas located within the Podyjí/Thayatal National Park and those in less protected parts of the valley, reflecting differences in the surroundings, namely the proportion of woody vegetation, degree of anthropogenic disturbance, game management, and conservation interventions. This suggests that the state of grassland vegetation is strongly linked to the surrounding landscape conditions and the effects of conservation management. Our research provides evidence that even these environmentally extreme habitats are undergoing significant long-term vegetation changes. Shifts toward ruderalized vegetation were more pronounced at sites outside of national parks, whereas sites in national parks exhibited slower and less extensive vegetation change, likely reflecting both the establishment of strict protection and historically lower anthropogenic pressure.
Ranunculus sect. Batrachium is one of the most taxonomically challenging groups of aquatic plants. The main factors contributing to this complexity include morphological reduction, phenotypic plasticity, polyploidy and hybridization. In this study, Batrachium diversity in the Pannonian Basin was investigated for the first time using molecular methods combined with morphological evaluation, genome size measurements and chromosome counting. Across 51 sampled populations, we identified seven traditionally recognized species known from other parts of central Europe, along with several hybrids, some of which have a complex origin involving backcrossing and introgression. Remarkably, we identified four previously unrecognized non-hybrid cytotypes, two of them belonging to the Ranunculus peltatus complex and two to the Ranunculus trichophyllus complex. DNA sequences indicate that these novel cytotypes are closely related to specific Mediterranean lineages of the European Batrachium species, either as their direct descendants or through unsampled or unknown ancestors closely related to them. The Pannonian Basin hosts a more diverse array of Batrachium lineages than previously described, including elements highly similar to Mediterranean lineages that are unique within central Europe, suggesting long-distance dispersal or relict persistence.
The fifteenth part of the series on the distributions of vascular plants in the Czech Republic includes grid maps of 87 taxa in the genera Asperugo, Bassia, Brunnera, Bupleurum, CoeloVentenata. These maps were produced by taxonomic experts based on examined herbarium specimens, literature and field records. The paper encompasses both native and alien taxa, representing diverse ecological groups, from terrestrial herbs inhabiting dry grasslands, ruderal sites and forests to submerged aquatic species and alien woody plants. It also continues the mapping of orchids, one of the most rapidly declining plant groups, with valuable implications for nature conservation. Almost half of the species covered are listed on the national Red List, including the critically threatened Bassia prostrata, Groenlandia densa, Potamogeton coloratus and P. praelongus, each now restricted to single sites, as well as Bupleurum affine, B. tenuissimum, Goodyera repens and Ventenata dubia, surviving only in few, isolated populations. Four species, namely Bassia laniflora, Herminium monorchis, Potamogeton compressus and P. friesii, are now nationally extinct. Among the alien taxa included, only Bassia scoparia has become invasive, while the others are mostly casual introductions or escapes. Four of the previously introduced neophytes, Bupleurum croceum, Rapistrum rugosum, Sclerolaena tricuspis and Sedobassia sedoides, are no longer recorded in the country. Particular attention is given to Cotoneaster, whose diversity has only recently been fully recognized and taxonomically evaluated, resulting in 22 distinguished escaped species. Spatial distributions and often also temporal dynamics of individual taxa are displayed in grid maps and documented by records included in the Pladias database and available in the Supplementary materials. Each map is accompanied by a commentary providing an analysis of distribution patterns, habitat descriptions, taxonomic notes and biological characteristics.
