Svatava Kubešová

Diversity of forest vegetation across a strong gradient of climatic continentality: Western Sayan Mountains, southern Siberia

Southern Siberian mountain ranges encompass strong climatic contrasts from the relatively oceanic northern foothills to strongly continental intermountain basins in the south. Landscape-scale climatic differences create vegetation patterns, which are analogous to the broad-scale vegetation zonation over large areas of northern Eurasia. In their southern, continental areas, these mountains harbour forest types which potentially resemble the full-glacial forests recently reconstructed for Central Europe. To identify forest vegetation–environment relationships in the southern Siberian mountain ranges, forest vegetation of the Western Sayan Mountains was sampled on a 280xa0km transect running from the northern foothills with oceanic climatic features to the continental Central Tuvinian Basin in the south. Based on the species composition, vegetation was classified into hemiboreal forests, occurring at drier and summer-warm sites with high-pH soil, and taiga, occurring at wetter, summer-cool sites with acidic soil. Hemiboreal forests included Betula pendula-Pinus sylvestris mesic forest, Larix sibirica dry forest and Pinus sylvestris dry forest. Taiga included Abies sibirica-Betula pendula wet forest, Abies sibirica-Pinus sibirica mesic forest and Pinus sibirica-Picea obovata continental forest. Hemiboreal forests were richer in vascular plant species, while taiga was richer in ground-dwelling cryptogams. Vegetation–environment relationships were analysed by indirect and direct ordination. Winter and summer temperatures and precipitation exerted a dominant influence on species composition. Soil pH was also an important correlate of species composition, but this factor itself was probably controlled by precipitation. At a more local scale, the main source of variation in species composition was topography, producing landscape patterns of contrasting plant communities on slopes of different aspects and valley bottoms. The response of tree species to major environmental factors was expressed with Huisman–Olff–Fresco models. Larix sibirica appeared to be most resistant to drought and winter frosts, Pinus sibirica was adapted to low temperatures both in winter and summer, and Picea obovata had an intermediate response to climate. Betula pendula, Pinus sylvestris and Populus tremula were associated with the warmest sites with intermediate precipitation, while Abies sibirica was the most moisture-demanding species, sensitive to deep winter frosts.

Environmentally acceptable effect of hydrogen peroxide on cave "lamp-flora", calcite speleothems and limestones.

Mosses, algae, and cyanobacteria (lamp-flora) colonize illuminated areas in show caves. This biota is commonly removed by a sodium hypochlorite solution. Because chlorine and other deleterious compounds are released into a cave environment during lamp-flora cleansing, hydrogen peroxide was tested as an alternative agent. In a multidisciplinary study conducted in the Kateinská Cave (Moravian Karst, Czech Republic), 12 algae- and cyanobacteria taxons and 19 moss taxons were detected. The threshold hydrogen peroxide concentration for the destruction of this lamp-flora was found to be 15 vol.%. Based on laboratory experiments in stirred batch reactors, the dissolution rates of limestones and calcite speleothems in water were determined as 3.77 x 10-3 and 1.81 x 10-3 mol m-2 h-1, respectively. In the 15% peroxide solution, the limestone and speleothem dissolution rates were one order of magnitude higher, 2.00 x 10-2 and 2.21 x 10-2 mol m-2 h-1, respectively. So, the peroxide solution was recognised to attack carbonates somewhat more aggressively than karst water. In order to prevent the potential corrosion of limestone and speleothems, the reaching of preliminary peroxide saturation with respect to calcite is recommended, for example, by adding of few limestone fragments into the solution at least 10 h prior to its application.

Diversity of bryophytes on treeless cliffs and talus slopes in a forested central European landscape

Abstract The bryophyte flora and its environmental correlates were studied on 28 treeless cliffs and 18 treeless talus slopes in forested river valleys of the southern Czech Republic. The diversity of bryophyte assemblages was assessed through species richness and spectra of distribution-rangetypes,growth forms and life strategies, using analysis of covariance. Species richness of cliffs increased with their area but this was not the case for talus slopes, where a high microtopographic heterogeneity appeared to be the key factor governing diversity. No habitat island effects weredetectedfor cliffs; there were no differences between isolated cliffs and cliffs found in the neighbourhood of other cliffs or talus slopes. Island effects were not studied for talus slopes as they were nearly always found in clusters with cliffs and other talus slopes. Talus slopes werecharacterizedby a strong effect of the ecotone between forest and open talus, with ecotonal vegetation being more diverse than the central part of talus slopes. However, no ecotone effect was found on cliffs. The effect of potential irradiation, used as a proxy for moisture availability,was weak on cliffsbut strong on talus slopes where more insolated slopes had lower diversity, more temperate and fewer boreal species, a predominance of short turf or cushion-like mosses over large bryophytes and a higher proportion of the colonist strategy, as opposed to perennial stayersand long-lived shuttlespecies. On cliffs, base-rich rocks had higher total species richness but a lower proportion of hepatics, fewer suboceanic and more submediterranean species, and more small turf or cushion-like mosses. The effect of base status was not assessed for talus slopes as theywere all formed fromacidic rocks. These results demonstrate that cliffs and talus slopes in the same area are quite different habitats and each is characterized by distinctive environmental conditions.

Plant species richness–productivity relationships in a low-productive boreal region

Local species richness–productivity (SR–P) relationship is usually reported as unimodal if long productivity gradients are sampled. However, it tends to be monotonically increasing in low-productive environments due to the decreasing part of the SR–P curve being truncated. Previous work indicated that this can hold true for forest herb layers, because of an upper bound on productivity caused mainly by canopy shading. Here, we ask whether the same pattern exists in a region with an upper bound on productivity caused by a harsh climate. We sampled herbaceous vegetation of boreal forests and grasslands in a low-productive region of central Yakutia (NE Siberia) with dry and winter-cool continental climate. We collected data on species composition, herb-layer productivity (aboveground herbaceous biomass), soil chemistry and light availability. We applied regression models to discriminate between monotonically increasing, decreasing and unimodal responses of herb-layer species richness to measured variables and analysed trends in the species-pool size and beta diversity along the productivity gradient. Our expectation of the monotonically increasing SR–P relationship was confirmed for neither forest herb layers nor grasslands. In the forest herb layers, no relationship was detected. In grasslands, the relationship was unimodal with species richness decline starting at much lower productivity levels than in more productive temperate grasslands. Potential causes for this decline are either limitation of local species richness by the species pool, which contains few species adapted to more productive habitats, or competitive exclusion, which can become an important control of species richness under lower levels of productivity than is the case in temperate grasslands.

Bryophytes on river gravel bars in the Balkan mountains: new records and insights into ecology

Abstract: Kalníková, V., Palpurina, S., Peterka, T., Kubešová, S., Plesková, Z. & Sabovljević, M. 2017. Bryophytes on river gravel bars in the Balkan mountains: new records and insights into ecology. — Herzogia 30: 370 –386. Gravel bars are a heterogeneous habitat on the border between the aquatic and terrestrial environments that can maintain a high diversity of bryophyte species. However, the bryoflora of river gravel bar habitats has rarely been explored, particularly in Southeastern Europe. We therefore carried out a two-year field survey on river gravel bars in selected mountains and foothills in the Balkan Peninsula, recording all bryophytes in 4×4 or 3×5 m plots. In total, we sampled 59 vegetation plots on 30 streams and rivers and recorded 85 bryophyte taxa. Here we report Bryum klinggraeffii (a new species for the floras of Albania, Montenegro and Serbia) and five data-deficient or vulnerable species. We found several drought-tolerant bryophytes on gravel bars, e.g. Barbula convoluta, Ceratodon purpureus and Tortella tortuosa, as well as typical hygrophilous species, e.g. Cinclidotus aquaticus, Fontinalis antipyretica and Platyhypnidium riparioides. The most common species in this transitional habitat were Brachythecium rivulare, Bryum argenteum, Oxyrrhynchium hians, Barbula unguiculata, Ceratodon purpureus and Bryum caespiticium. Dentrended correspondence analysis ordination technique identified the complex gradient of moisture and light conditions as the main environmental factor for bryophyte communities on the studied gravel bars.

Results of the bryofloristic courses of the Department of Botany, University of South Bohemia, in 2012 and 2013

Abstract We present the bryofloristic results of three field courses, which took place in different regions of the Czech Republic in 2012 and 2013. The regions included the northern part of České středohoří hills of North Bohemia, the Žďárské vrchy Mts of East Bohemia and the warm South Moravian region between Hustopeče and Kyjov. Altogether 307 species and four additional varieties (more than one-third of the known country’s bryoflora) were recorded in course of all three events, with species counts from the individual 4-days-courses varying between 133 and 187 evaluated taxa. Most important records are briefly commented.