Eleven plants of Asplenium platyneuron (ebony spleenwort) were found in disturbed serpentine woodland in south-central Slovakia (Central Europe). This find represents a new addition to the fern flora of Europe. It is probably the result of long-distance spore dispersal. The nearest known sites for this species are those in eastern North America, about 6500 km away. The important determination characters of A. platyneuron are described, the Slovakian locality characterized and an overview of the ecology and a map of the worldwide distribution of this species provided.
Biometric relationships between bone dimensions and body size are presented for topmouth gudgeon Pseudorasbora parva and sunbleak Leucaspius delineatus, two invasive fish species in the UK. This study also provides a tool for identification of these species using key bones. Such information facilitates the assessment of the potential role of these invaders in the diet of piscivorous fauna.
Conyza bonariensis (L.) Cronquist and C. triloba Decne. are reported as new alien species to the Czech Republic and Europe, respectively. Conyza bonariensis was collected in 1964 and 1965 in two localities in N Bohemia; the specimens are deposited in PRA. In both cases, the plants were introduced with cotton and occurred in areas of textile factories. Conyza triloba was collected once at the pond in the village of Černivsko in S Bohemia in 1971; the specimen is deposited in PR. The mode of introduction is unknown.
Cyperus eragrostis Lam. was first recorded in the Czech Republic in an empty water reservoir at Jablonec nad Nisou (N Bohemia) in 1999. In this study, herbarium specimens of C. eragrostis in large herbaria in the Czech Republic were revised and the invasion of Europe by this species was reviewed. A brief description of C. eragrostis is given, distribution map of the temporal course of its invasion is presented and the species’ ecology in Europe characterized. Accompanying vegetation and results of the analyses of soil from the site are described. How the plant reached this locality remains unknown. The occurrence was only ephemeral as the only tussock was destroyed when the water reservoir was refilled.
Comparative studies of closely related species may provide useful insights into the effect of species traits on invasion success since some of the biases associated with multispecies studies, such as phylogenetic effects, are considerably reduced by virtue of the experimental design. In this study seed and seedling traits of three congeneric alien species in Europe, differing in their region of origin, invasion status and history (Impatiens glandulifera, I. parviflora, I. capensis), were compared with the native I. noli-tangere in laboratory and common garden experiments. Seeds of I. glandulifera required the shortest period of stratification, germinated well both under laboratory and experimental garden conditions and the seedlings produced more biomass than those of the other species. Seeds of I. parviflora required a longer period of stratification, had the highest percentage germination but seedling emergence in the experimental garden was poorer than in I. glandulifera. Neither of these two species invasive in the Czech Republic formed soil seed banks. The native I. noli-tangere had the lowest percentage germination and formed a short-term persistent seed bank. Impatiens capensis germinated well in the laboratory, had the highest seedling emergence in the garden and its seed remained viable in the soil for three years. This indicates that in terms of germination and emergence, this species is comparable with the two invasive alien congeners and there appear to be no constraints to its invasion in the Czech Republic where it does not occur yet. Its absence may be due to a low propagule pressure; in the national flora I. capensis is listed as a potential future invader without mentioning it being cultivated in this country. Our results indicate that differences in the invasiveness of three alien species of balsams in the temperate zone of Central Europe can be attributed, at least in part, to their differing performances in the early stages of their life cycle. The short period of time required for seed stratification and the high seedling biomass of I. glandulifera might have increased its invasion potential compared to other Impatiens species occurring in the Czech Republic.
Following the opening of the Rhine-Main-Danube waterway in 1992 the invasive gobiid Proterorhinus marmoratus started colonizing the River Main and the River Rhine. In 2005, point abundance sampling revealed the presence of the species in two impoundments of the River Moselle next to the confluence with the River Rhine. This distribution pattern suggests that tubenose goby actively immigrated into the River Moselle by using locks and fishways. Highest population densities were recorded in lentic to slightly lotic habitats in headwater reaches of weirs as well as in oxbow lakes and groyne fields. Due to regulation by weir and lock systems, the River Moselle and its largest tributary the River Saar offer numerous suitable habitats facilitating the rapid further expansion upstream to river reaches in Luxembourg and France.
Glyceria striata (Lam.) Hitchc., a species native to North America, was found as an alien species on several localities in the Hostýnské vrchy Mts (eastern Moravia). It grows there on disturbed sites in artificial, usually spruce and alder woods at an altitude of 340–550 m a.s.l. The way of introduction of G. striata to this area is uncertain. However, it is present as an alien in many European countries. A detailed synonymy and description of species is given. Taxonomy and systematics are shortly discussed and determination key within the Czech species of the genus Glyceria is also given. Notes on the distribution and the history of naturalization of the species in Europe as well as notes on its ecology are included.
Examples of Taraxacum species (sect. Ruderalia) that have a well-known main distribution area and, a few rather isolated, obviously introduced occurrences, are given. The lack of a long tradition of specific knowledge and collection of Taraxacum sect. Ruderalia specimens have impeded our understanding of the origin of the present distributions. Some views are presented. Taraxacum ancistratum, T. crassum, T. deltoidifrons, T. infuscatum, T. jugiferum, and T. lundense, all belonging to Taraxacum sect. Ruderalia, are described as new species. Three or four of these species were first found as introductions far away from their supposed main distribution area.
Following their first appearance, the invasive fishes Pseudorasbora parva and Perccottus glenii have been in Lithuania for several decades. However, until recently, information relating to their distribution and secondary spread was limited. For this reason, suitable habitats for these fish species were surveyed for their presence across the entire country. Additionally, all previously reported records on the presence of these species were summarized. Results revealed P. glenii to be widely distributed within the country with abundant populations in habitats suitable for the species. The recent distribution of P. parva is restricted to only a few water bodies. It was shown that both species are associated with human mediated transfer, while no natural dispersal of these invasive species was observed. The results of this study suggest that the invasion of Lithuanian inland waters by P. parva and P. glenii is still ongoing, and their occurrence in numerous water bodies, which are still devoid of these species, now seems probable. Demonstrated vectors of P. parva and P. glenii introductions in Lithuania highlight the importance of controlling and screening human activities related to aquaculture, recreational angling and the ornamental fish trade in order to restrict further P. glenii and P. parva expansion in this region.