Dušan Senko

Cytotype distribution patterns, ecological differentiation, and genetic structure in a diploid-tetraploid contact zone of Cardamine amara.

UNLABELLED • PREMISE OF THE STUDY Contact zones between diploids and their autopolyploid descendants represent a unique evolutionary venue for studying polyploid establishment, cytotype coexistence, and interactions. Here, we examine cytotype coexistence in a diploid-tetraploid contact zone of a perennial herb, Cardamine amara, located north of the Alps by assessing cytotype spatial patterns, ecological divergence, and genetic variation and structure.• METHODS Flow cytometry was applied to screen DNA ploidy levels in 302 populations (3296 individuals) and the genetic variation of a selection of 25 populations was examined using microsatellite and AFLP markers. Environmental (landscape and climatic) data were analyzed to assess ecological differentiation between the cytotypes.• KEY RESULTS A parapatric distribution of the cytotypes with a relatively wide (over 100 km in some regions) secondary contact zone was identified. Mixed-ploidy populations, documented for the first time in this species, as well as triploid individuals were found along the diploid-tetraploid borderline. Different climatic requirements of the two main cytotypes were revealed, mirrored in their altitudinal separation. The tetraploids were genetically differentiated from both the diploids and the modeled, in silico autotetraploid genotypes, in accordance with the assumed polyploid origin and spread linked to past glaciations, and largely independent evolution in allopatry.• CONCLUSIONS The observed spatial and genetic patterns likely reflect the evolutionary and colonization history of the two cytotypes and have been maintained by multiple factors such as ecological divergence, limited gene flow between the cytotypes, and the restricted dispersal capacity.

Fifty years of plant invasion dynamics in Slovakia along a 2,500 m altitudinal gradient

Knowledge on the main spatiotemporal trends in plant invasions of habitats is essential for a better understanding of the process of these invasions. The aim of this study was to determine the level of plant invasion, represented by relative richness and total cover of archaeophytes and neophytes, in 45 EUNIS habitat types along with spatiotemporal changes in invasion level with increasing altitude and time in Slovakia. In general, the most invaded habitats are those which are highly influenced by human activities. Generalized linear models and generalized linear mixed models were used to assess the associations between habitat-specific invasion level, altitude and time, respectively. There is a general decrease in the relative richness and total cover of archaeophytes and neophytes with increasing altitude in the invaded habitats. There is also an observable temporal trend in archaeophytes shifting from anthropogenic towards more natural habitats. Importantly, the relative neophyte richness has recently been increasing, predominantly in semi-natural and natural habitats, which brings about major concerns for nature conservation. This may be the manifestation of a lag phase in the dispersal of neophytes. However, accompanied with a significant increase in the relative richness of archaeophytes in some natural habitats, it may indicate more complex changes in the invaded habitats and be an early warning sign for ecological degradation of these habitats.

The impact of forest management on changes in composition of terricolous lichens in dry acidophilous Scots pine forests

This study focuses on dry acidophilous Scots pine forests, well known for their high biodiversity of cryptogams. We hypothesized that dense forests and heavy management were responsible for changes in species diversity, decreasing trends in lichen cover and increasing moss cover. This hypothesis was tested in three types of Scots pine forests maintained under three different management regimes: 1) managed forests (forest plantations regenerated by planting), 2) semi-natural forests (forest plantations regenerated naturally), both located in the Borska nižina lowland in SW Slovakia, and 3) natural forests (primordial vegetation without visible management actions from the association Cladonio-Pinetum Juraszek 1928), located in the Bory Tucholskie National Park, NW Poland. We observed that the cover of the canopy tree layer had the most significant influence on the diversity of lichens. Managed forests are planted and maintained to achieve denser tree stocking, and although the environmental conditions created appear optimal for moss species, they are less suitable for terricolous lichens.

Vitality of the cyanolichen Peltigera praetextata exposed around a cement plant (SW Slovakia): a comparison with green algal lichens

Abstract The suitability of the cyanolichen Peltigera praetextata (Sommerf.) Zopf as indicator of the effects of air pollution around a cement industry was investigated. For this purpose, lichen samples taken from an unpolluted site were exposed for 1–6 months at selected sites (a cement mill, two quarries, inhabited and agricultural sites) in SW Slovakia: physiological parameters and ultrastructural features were examined prior and after exposure. The responses of P. praetextata were then compared with those of the green-algal lichens Evernia prunastri and Xanthoria parietina co-located at the same sites. The performance of the cyanobacterial photobiont of P. praetextata (as reflected by the maximum quantum yield of primary photochemistry FV/FM and by the performance index PIABS) was negatively influenced mainly by the length of exposure in the urban and agricultural sites and less by dust pollution around the cement mill and the quarries. A significant increase in membrane lipid peroxidation products reflected the effects of oxidative stresses in all sites. The alteration of the content of water soluble proteins was detected in the samples exposed around the cement mill, while dehydrogenase activity did not show any significant pattern. Similarly to green algal lichens, ultrastructural alterations featured lipid droplets increase, swelling of cellular components, thylakoid degeneration and sometimes plasmolysis, which on the whole gave the cells an aged appearance, especially in the urban and agricultural sites. On the whole, E. prunastri confirmed to be the most sensitive to dust pollution, P. praetextata was likely influenced by microclimatic conditions and habitat eutrophication and X. parietina was the most resistant. When compared with green-algal lichens, P. praetextata was not the best indicator of the effects of cement dust pollution.

Role of infrastructure and other environmental factors affecting the distribution of alien plants in the Tatra Mts

Alien plants, although usually rare in mountain habitats, can significantly impact native species diversity. The aim of this study was to analyse patterns of alien plant distribution in the Tatra Mts (Slovakia), focusing primarily on comparison of various transportation routes as a conduit for the spread of alien plants. We collected data on transects along: (i) railways, (ii) paved roads with unlimited access, (iii) tourist routes in mountain valleys (paved and unpaved roads, footpaths) with limited access and (iv) plots in areas surrounding mountain chalets. The majority of alien plants were found in locations at lower elevations and with intensive human activity. Patterns of distribution along the main corridors in the Tatras reflect the intensity and manner of use of each transportation route. Paved roads with unlimited access and railways are used most frequently and host the greatest number of alien species. Our observations show that the mode of access of these routes is more important than the road surface. Roads with limited vehicular access, be it unpaved and paved, are very similar in their alien species richness, while paved roads with limited and unlimited access significantly differ. Footpaths that cannot be accessed by vehicles are almost free of alien plants, even though they are found in the widest elevation range and often parallel to roads in the same valley. Other factors significantly negatively affiliated with alien species richness were elevation, cover of the tree and moss layer and moisture, and positively affiliated with the amount of nutrients.