The composition of the vegetation of fishpond mires in the Třeboň Basin (Czech Republic) was studied in relation to temporal fluctuations in certain environmental factors. The water-table depth, water pH and electrical conductivity at 49 permanent plots were measured at approximately threeweek intervals from March to October 2003. Minimum, maximum, mean, median and variation in the above-mentioned environmental factors were correlated with vegetation composition. The most important environmental factors explaining the variation in vegetation were mean pH and maximum water-table level. Median conductivity increased with increase in waterlogging and eutrophication. Some seasonal trends in the dynamics of these parameters were observed. The lowest conductivity was in spring, increased continuously throughout summer and peaked in autumn. In contrast, water level decreased in summer, when evapotranspiration was greatest, and rose in autumn after heavy rainfall. The pH increased from March to June, then was stable and decreased at the end of summer. Seasonal trends were generally identical in all vegetation types. The fluctuations in the environmental factors were so considerable that they may influence the reliability of vegetation environmental analyses.
Central European lowland wet meadows are habitats of great conservation interest, however, their phytosociological status has been to a large extent dependent on specific phytosociological traditions in different countries. In order to bridge the gaps between different national schemes of vegetation classification, a statistical analysis of variation in species composition of these meadows in the Czech Republic, E Austria, Slovakia, Hungary and NE Croatia was performed, using a data set of 387 geographically stratified vegetation relevés sampled at altitudes < 350 m. Principal coordinates analysiswas used to identify and partial out the noise component in the variation in this data set. The relevés were classified by cluster analysis. A new method for identifying the optimal number of clusters was developed, based on species fidelity to particular clusters. This method suggested the optimum level of classification with three clusters and secondary optimum levels with five and nine clusters. Classification based on three clusters separated the traditional phytosociological alliances of Calthion palustris and Molinion caeruleae, both with a suboceanic phytogeographical affinity, and a group of flooded meadows of large river alluvia, with a continental affinity. The latter group included the traditional alliances of Agrostion albae, Alopecurion pratensis, Cnidion venosi, Deschampsion cespitosae and Veronico longifoliae-Lysimachion vulgaris; however, the internal heterogeneity of this group did not reflect putative boundaries between these alliances as proposed in the phytosociological literature. Therefore we suggest to unite these alliances in a single alliance Deschampsion cespitosae Horvatić 1930 (the oldest valid name). Classification with nine clusters was interpreted at the level of broad phytosociological associations. Particular clusters were characterized by statistically defined groups of diagnostic species and related to macroclimatic variables.
We reviewed 37 studies on vegetation succession in which the succession started on bare ground, was followed in at least six sites, and where these sites were spatially separated over at least 10 km2. The effect of environmental factors, which were explored in at least five studies, on the course of succession was assessed, based on the proportion of significant and non-significant results. Surrounding vegetation, macroclimate, soil moisture, amount of nitrogen and soil texture appeared to have the highest influence on the course of succession. Less influential were the size of a disturbed site, pH, organic matter and phosphorus content. Surrounding vegetation exhibited a significant effect in all cases where this was considered. These results imply that succession cannot be studied without the landscape context. The large-scale approach to succession has the potential to contribute substantially to both the theory of succession and practical applications, especially in restoration ecology.
Typology of dry-mesic oak forest vegetation of Slovakia is presented. Seven vegetation types were distinguished based on a Braun-Blanquetian relevé data analysis using a TWINSPAN classification algorithm. The identified vegetation types are related to seven syntaxa traditionally used by Central European phytosociologists: dry-mesic oak forest on sandy soils – Carici fritschii-Quercetum roboris, dry-mesic oak forest on heavy soils – Potentillo albae-Quercetum, dry-mesic oak forest on basic rocky substrates – Corno-Quercetum, dry-mesic oak forest on acidic substrates – Sorbo torminalis-Quercetum, dry oak forest on loess – Quercetum pubescenti-roboris, dry-mesic oak forest on loess – Convallario-Quercetum roboris, dry-mesic forest of Turkey oak – Quercetum petraeae-cerris. Detrended correspondence analysis was used to visualize the similarity of vegetation types. Some aspects of dry-mesic oak forest ecology, distribution and dynamics in Slovakia are discussed; their general retreat due to mesophilous tree species expansion is stressed.
During the last decade many electronic databases of vegetation plots, mainly phytosociological relevés, were established in different European countries. These databases contain information which is extremely valuable for both testing various macroecological hypotheses and for nature conservation surveying or monitoring. The aim of this paper is to provide estimates of the number of vegetation plots there are in Europe, how many are stored in an electronic format and to assess their distribution across European countries and regions.We sent a questionnaire to the managers of national or regional databases of vegetation plots and other prominent vegetation ecologists. Meta-data obtained in this way indicate that there are > 4,300,000 vegetation-plot records in Europe, of which > 1,800,000 are already stored electronically. Of the electronic plots, 60% are stored in TURBOVEG databases. Most plot records probably exist in Germany, the Netherlands, France, Poland, Spain, Czech Republic, Italy, UK, Switzerland and Austria. The largest numbers of plots per unit area are in the Netherlands, Belgium, Denmark and countries of central Europe. The most computerized plots per country exist in the Netherlands (600,000), followed by France, the Czech Republic and the UK. Due to its strong phytosociological tradition, Europe has many more vegetation plots than any other part of the world. This wealth of unique ecological information is a challenge for future biodiversity studies. With the alarming loss in biodiversity and environmental problems like global warming and ongoing changes in land use, there is an urgent need for wide-scale scientific and applied vegetation research. Developments of information systems such as SynBioSys Europe and facilitation of data flow between the national and regional databases should make it easier to use these vegetation-plot data.
Věkem podmíněná makulární degenerace (VPMD) je v rozvinutých zemích nejčastější příčinou ztráty zraku lidí starších 55 let. Vlhká forma této choroby je příčinou těžké ztráty zraku u 90 % postižených. VPMD vzniká spolupůsobením genetických faktorů a faktorů životního stylu. Klíčovým mechanizmem vzniku vlhké formy VPMD je novotvorba cév, stimulovaná růstovým faktorem VEGF. Léčbou volby VPMD jsou proto preparáty anti-VEGF, podávané formou injekcí do sklivce. V mezinárodních studiích jsou zkoumány nové léky na VPMD. Léčbu je třeba zahájit včas, dokud není vážně postižena zraková ostrost., Age-related macular degeneration (AMD) is the most common cause of vision loss in developed countries in people older than 55 years. The wet form of this disease is the cause of severe vision impairment in 90 percent of patients. AMD develops as a result of an interaction between genetic and lifestyle factors. The key mechanism in the development of wet AMD is the growth of new vessels, stimulated by the vascular endothelial growth factor (VEGF). The treatment of choice is, therefore, the use of anti-VEGF agents administered as intravitreal injections. International clinical studies are evaluating new AMD treatments. It is necessary to start the treatment early, before severe visual impairment occurs., I. Fišer, and Lit.: 20