Knowledge of biological invaders in Europe is used for setting future research priorities
The DAISIE project of the EU 6th Framework Programme was aimed at collating existing data about invasive organisms in Europe into a pan-European database; this data has been up to now scattered in grey literature and unpublished. The resulting open-access database (www.europe-aliens.org) includes information about 11,000 non-native species of vascular plants, fungi, invertebrates and vertebrates in terrestrial, freshwater and marine ecosystems of Europe. The data was analysed in a monograph, which summarizes historical, geographical and ecological trends in particular taxonomic/environmental groups and evaluates the impact of biological invaders on invaded ecosystems and presents a complete list of alien species in Europe; this list captures status quo of biological invasions in Europe and will serve as a reference data set for evaluating future trends and effectiveness of adopted measures against invasive species. The results of the DAISIE project revealed that the number of naturalized alien species in Europe is much higher than previously thought. A warning signal is that in the dynamics of increase in alien species numbers shows deccelaration in none of the taxonomic groups considered; rather the opposite is trues (DAISIE 2009). The Botanical Institute took major part in the plant part of the project. Alien flora of Europe consists of 5789 species, of which 3749 species are naturalized; 1780 naturalized species arrived from other continents (the remaining are native to part of Europe and invading in another part outside their native distribution range). Currently, six new naturalized species are recorded each year in Europe (Lambdon et al. 2008, Pyšek et al. 2009; Fig. 1). The data from DAISIE project were used as a reference data set in a study assessing geographical biases in research on bilogical invasions (Fig. 2). Some regions, such as Africa and Asia, are disproportionally little studied (related to the actual number of plant invaders), which leads to the lack of information on invasions occurring in regionally specific habitats. Taxonomic bias is minor (all major taxonomic groups of invaders are fairly well covered) but most information on mechanisms of invasions comes from case studies of a limited number of highly invasive species. Therefore, it seems plausible to shift the research focus more towards naturalization, i.e. the part of the process which determines successful establishment of a species in a new regions; this phase is also crucial for our understanding of how invasions work (Pyšek et al. 2008). Thanks to the DAISIE initiative, Europe has become a continent with the most comprehensive knowledge of its alien species, and the results has become an information basis for the recently released European Commision policy options for EU strategy on invasive species (press release no. IP/08/1890).
Fig. 1. Dynamics of increase in numbers of alien plant species in Europe, shown separately for arrivals from other continents (alien to Europe) and with native distribution in part of Europe and invading elsewhere in the continent (from Lambdon et al., Preslia 2008).
Fig. 2. Geographical bias in invasion ecology. Numbers of plant species studied in regions of the world are related to the total numbers of naturalized species in these regions. Values are standardized. Regions below the line of unity are less intensively researched, in terms of species addressed in case studies, then would correspond to their proportional contribution to the global pool of naturalized plant species, and vice versa; the ratio of studied to naturalized species is indicated following the name of the region (from Pyšek et al., Trends in Ecology and Evolution 2008).
DAISIE 2009. Handbook of alien species in Europe. Springer, Berlin (ed. W. Nentwig, P.E. Hulme, P. Pyšek & M. Vilà); Pyšek P., Lambdon P., Arianoutsou M., Kühn I., Pino J. & Winter M.: Alien vascular plants of Europe. In: DAISIE (eds), Handbook of alien species in Europe, p. 43–61, Springer, Berlin (2009).
Lambdon P.W., Pyšek P., Basnou C., Hejda M., Arianoutsou M., Essl F., Jarošík V., Pergl J., Winter M., Anastasiu P., Andriopoulos P., Bazos I., Brundu G., Celesti-Grapow L., Chassot P., Delipetrou P., Josefsson M., Kark S., Klotz S., Kokkoris Y., Kühn I., Marchante H., Perglová I., Pino J., Vilà M., Zikos A., Roy D. & Hulme P.E.: Alien flora of Europe: species diversity, temporal trends, geographical patterns and research needs. Preslia 80: 101–149 (2008).
Pyšek P., Richardson D.M., Pergl J., Jarošík V., Sixtová Z. & Weber E.: Geographical and taxonomic biases in invasion ecology. Trends in Ecology and Evolution 23: 237–244 (2008).
New ecologically sustainable measures for the management of cyanobacterial water blooms in aquatic ecosystems
We tested 31 phtalocyanines, (patented in medicine for photodynamic treatment of carcinomes, some of them we already proved as potential algicides before). Cationic phtalocyanonides with substituted heterocycle were selected as the most promising (Jančula et al. 2008a). The experiments focused on the virioplankton proved that viral particles are an abundant and dynamic group of pelagic communities in river ecosystems (Fig. 1). There is a long way to practical use of viruses for management of cyanobacterial blooms, but the first step was to set up methods of their detection. We are the only lab in the Czech Republic, where virioplankton can be detected. Mutual correlations between virioplankton, its host and nutrient contents in the rivers studied indicate that the abundance and dynamics of virioplankton communities can be affected by phospohorus (Slováčková & Maršálek 2008). Our previous research showed that silvercarp was not an efficient tool for the direct management of cyanobacterial water blooms, but recent experiments with nile tilapia show, that photosynthetic activity of cyanobacteria decreased to zero by passing through the gut of this fish (Jančula et al. 2008b). Integrated toxicity assessment of sediments is a useful tool for the ecotoxicological evaluation of sediment quality and should be used in cases, where aquatic ecosystems are to be restored by sediment dredging. We developed a direct test of sediment toxicity, which is sensitive and more reliable than tests based on sediment extraction (Smutná et al. 2008).
Fig. 3. The abundance of virioplankton in river ecosystems is about one order higher than that of bacterioplankton (from Slováčková & Maršálek, Aquatic Sciences 2008).
Jančula D., Drábková M., Černý J., Karásková M., Kořínková R., Rakušan J. & Maršálek B.: Algicidal activity of phthalocyanines-screening of 31 compounds. Environmental Toxicology 23: 218–223 (2008a).
Jančula D., Míkovcová M., Adámek Z. & Maršálek B.: Changes in the photosynthetic activity of Microcystis colonies after gut passage through Nile tilapia (Oreochromis niloticus) and silver carp (Hypophthalmichthys molitrix). Aquaculture Research 39: 311–314 (2008b).
Slováčková H. & Maršálek B.: Virioplankton and microbial communities in two Czech rivers (Svratka and Morava Rivers). Aquatic Sciences 70: 282–291 (2008).
Smutná M., Hilscherová K., Pašková V. & Maršálek B.: Biochemical parameters in Tubifex tubifex as an integral part of complex sediment toxicity assessment. Journal of Soils and Sediments 8: 154–164 (2008).
Spontaneous succession or technical reclamation as tools for restoration of vegetation in disturbed habitats
Vegetation development was studied in gravel-sand pits, spoil heaps from brown coal mining, abandoned fields and spruce forests attacted by bark-beetles. The results contributed to answering the question if we can rely on spontaneous succession or a technical restoration is needed. The most disturbed sites exhibit a high potential to recover by spontaneous succession. This may be applied not only to disturbed sites in the Czech Republic but probably to others in the temperate climate. Vegetation development is influenced predominantly by the presence of target vegetation in a close vicinity (up to 100 m), land use in the surrounding landscape and local site factors, especially moisture, nutrients and pH. Reaching a target stage by spontaneous succession is limited if the surrounding vegetation largely differs and local site factors are altered. Spontaneous succession is not very effective either in highly productive sites where establishment of target species is restricted by a strong competitor. Under such situations, technical reclamation may be preferred. Preferrence for spontaneous succession or technical reclamation is to a large extent determined by the position of a disturbed site along the productivity-stress gradient (Fig. 1).
Fig. 1. Relative preference of spontaneous succession and technical reclamation along the productivity-stress gradient (from Prach & Hobbs, Restoration Ecology 2008).
Jonášová M. & Prach K.: The influence of bark beetles outbreak vs. salvage logging on ground layer vegetation in Central European mountain spruce forests. Biological Conservation 141: 1525–1535 (2008).
Frouz J., Prach K., Pižl V., Háněl L., Starý J., Tajovský K., Materna J., Balík V., Kalčík J. & Řehounková K.: Interactions between soil development, vegetation and soil fauna during spontaneous succession in post mining sites. European Journal of Soil Biology 44: 109–121 (2008).
Prach K., Lepš J. & Rejmánek M.: Old field succession in central Europe: local and regional patterns. In: Cramer V.A. & Hobbs R.J. (eds), Old fields: dynamics and restoration of abandoned farmland, p. 180–201, Island Press (2007).
Prach K. & Hobbs R.J.: Spontaneous succession vs. technical reclamation in the restoration of disturbed sites. Restoration Ecology 16: 363–366 (2008).
Řehounková K. & Prach K.: Spontaneous vegetation succession in gravel-sand pits: a potential for restoration. Restoration Ecology 16: 109–121 (2008).
Checklist and Red List of lichens of the Czech Republic
In the published Red List, the threat of the Czech lichen flora is classified for the first time by using international criteria (IUCN version 3.1). The Red List serves also as a new version of the checklist, with changes to the previously published Catalogue of the Czech lichen flora (Vězda & Liška 1999) indicated. In total, 1497 species are included. More than a third of all species (37.4%) are threatened, almost a quarter of these (8.7% of the total number of species) critically. Almost one tenth of the total number of species is considered extinct in the Czech Republic, and only about one eighth are not endangered. The published work will make it possible to focus future research on the most threatened lichens, and the application of international criteria will allow to compare the situation in the Czech Republic with other European countries (Liška et al. 2008). Besides this complex evaluation of the Czech lichen flora, field studies are carried out aimed at the assessment of stress factors damaging to the lichen flora and at ongoing changes in its composition. Air pollution, mainly by sulphur dioxide, and eutrophication are the most important among these factors. The results of an 18 years lasting monitoring of 139 trees representing sites of epiphytic lichens, which are most susceptible to air pollution, made it possible to evaluate the effects of the distance from pollution source, type of substrate, altitude, and bark eutrophication on the susceptibility of lichen species to air pollution. Changes over time in species composition depended on the position of the tree in landscape and on the initial species composition. The lichen flora on trees affected by eutrophication exhibited less changes; this indicates that the effect of eutrophication (mainly increased bark pH) may reduce the damaging effect of air pollution (Liška & Herben 2008). Research also aims at case studies of individual species; for example, the distribution of Physcia aipolioides has been revised in cooperation with Slovak and Hungarian lichenologists (Lisická et al. 2008).
Liška J., Palice Z. & Slavíková Š.: Checklist and Red List of lichens of the Czech Republic. Preslia 80: 151–182 (2008).
Liška J. & Herben T.: Long-term changes of epiphytic lichen species composition over landscape gradients: an 18 year time series. Lichenologist 40: 437–448 (2008).
Lisická E., Lackovičová A., Liška J., Lőkös L. & Lisický M. J.: Physcia aipolioides – ein Beispiel einer invasiven Flechte oder einer unterschätzten Verbreitung? Sauteria 15: 303–318 (2008).