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23. Maps of the level of invasion of the Czech Republic by alien plants

Creator:
Chytrý, Milan, Wild, Jan, Pyšek, Petr, Tichý, Lubomír, Danihelka, Jiří, and Knollová, Ilona
Type:
article and TEXT
Subject:
altitude, archaeophyte, distribution, exotic species, habitat types, invasive species, land cover, neophyte, non-native species, and plant community
Language:
English
Description:
A series of maps showing the level of invasion of the Czech Republic by alien plants was developed based on a quantitative assessment of the level of invasion of 35 terrestrial habitat types at different altitudes. The levels of invasion were quantified for 18,798 vegetation plots, using two measures: proportion of the species that are aliens and total cover of alien species. Separate assessments were made for archaeophytes and neophytes. Within each habitat, the level of invasion was related to altitude using generalized linear models. The level of invasion, depending on the measure used, decreased with altitude in 16 out of 20 habitats for archaeophytes and 18 out of 23 for neophytes. In two habitats, one measure of the level of invasion increased with altitude for archaeophytes. The values of the level of invasion predicted by generalized linear models for particular combinations of habitats and altitudes were projected onto a land-cover map and digital elevation map of the country. Four maps showing the level of invasion were produced, based on the proportion of the species that are archaeophytes or neophytes, and cover of archaeophytes and neophytes. The maps show that both archaeophytes and neophytes are most common in lowland agricultural and urban areas, whereas they are sparsely represented in mountainous areas. At middle altitudes, agricultural areas are more invaded than forested areas. Outside agricultural and urban areas, high levels of invasion are found especially in lowland sandy areas and river corridors.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/

25. Naturalized plants have smaller genomes than their non-invading relatives: a flow cytometric analysis of the Czech alien flora

Creator:
Kubešová, Magdalena, Moravcová, Lenka, Suda, Jan, Jarošík, Vojtěch, and Pyšek, Petr
Type:
article and TEXT
Subject:
alien plants, confamilials, congeners, C-value, flow cytometry, genome size, invasive species, large genome constraint hypothesis, nuclear DNA content, and plant invasions
Language:
English
Description:
Genome size has been suggested as one of the traits associated with invasiveness of plant species. To provide a quantitative insight into the role of this trait, we estimated nuclearDNAcontent in 93 alien species naturalized in the Czech Republic, belonging to 32 families, by using flow cytometry, and compared it with the values reported for non-invading congeneric and confamilial species from the Plant DNA C-values database. Species naturalized in the Czech Republic have significantly smaller genomes than their congeners not known to be naturalized or invasive in any part of the world. This trend is supported at the family level: alien species naturalized in the Czech flora have on average a smaller genome than is the mean value for non-invading confamilials. Moreover, naturalized and non-invading species clearly differed in the frequency of five genome size categories; this difference was mainly due to very small genomes prevailing and intermediate to very large genomes underrepresented in the former group. Our results provide the first quantitative support for association of genome size with invasiveness, based on a large set of alien species across a number of plant families. However, there was no difference in the genome size of invasive species compared to naturalized but non-invasive. This suggests that small genome size provides alien plants with an advantage already at the stage of naturalization and need not be necessarily associated with the final stage of the process, i.e. invasion.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/

26. Oenothera coronifera, a new alien species for the Czech flora, and Oenothera stricta, recorded again after nearly two centuries

Creator:
Mihulka, Stanislav, Pyšek, Petr, and Pyšek, Antonín
Type:
article and TEXT
Subject:
Alien plants, casual occurrence, Oenothera, Onagraceae, new record, and Czech Republic
Language:
English
Description:
Two species of the North American genus Oenothera are reported as aliens in the Czech Republic. A population of O. coronifera consisting of ca. 30 plants at various phenological stages, from rosettes to flowering plants, was found in 2001 at the railway station in the town of Zliv, district of České Budějovice, S Bohemia. The species was probably introduced via the railway and is the first record of this species for the Czech Republic. A single plant of O. stricta, previously reported from the bank of the Vltava river in Prague, in 1825, was found as a weed in a private garden in the village of Vroutek, district of Louny, N Bohemia, in 2000. This is the second record of this species from the Czech Republic in 175 years. The seed of O. stricta was probably introduced to the site from abroad and the record suggests that the occurrence of casual alien plants is highly unpredictable. It is argued that botanists studying alien plants, given their special interest in sites where these plants occur, may directly contribute to the enrichment of checklists of national alien floras.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/

28. Plant species of the Central European flora as aliens in Australia

Creator:
L. Phillips, Megan, Murray, Brad R., Pyšek, Petr, Pergl, Jan, Jarošík, Vojtěch, Chytrý, Milan, and Kühn, Ingolf
Type:
article and TEXT
Subject:
alien plants, Australia, Central Europe, growth form, introduction history, naturalization, residence time, and source-pool approach
Language:
English
Description:
The Central European flora is an important source pool of plant species introduced to many regions throughout theworld. In this study,we identified a total of 759 plant species of the Central European flora that are currently recognized as alien species in Australia. We explored temporal patterns of introduction of these species to Australia in relation to method of introduction, growth form, naturalization status and taxonomy. Across all species, substantially larger numbers of species were introduced between 1840 and 1880 as well as between 1980 and the present, with a small peak of introductions within the 1930s. These patterns reflect early immigration patterns to Australia, recent improvements in fast and efficient transportation around the globe, and emigration away from difficult conditions brought about by the lead up to the Second World War respectively. We found that the majority of species had deliberate (69%) rather than accidental (31%) introductions and most species have not naturalized (66% casual species, 34% naturalized species). A total of 86 plant families comprising 31 tree species, 91 shrub species, 533 herbaceous species and 61 grass species present in Central Europe have been introduced to Australia. Differential patterns of temporal introduction of species were found as a function of both plant family and growth form and these patterns appear linked to variation in human migration numbers to Australia.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/

30. Regional species pools of vascular plants in habitats of the Czech Republic

Creator:
Sádlo, Jiří, Chytrý, Milan, and Pyšek, Petr
Type:
article and TEXT
Subject:
alien, archaeophyte, habitat classification, local and regional processes, native, neophyte, species richness, and vegetation type
Language:
English
Description:
Based on a combination of data from the Czech National Phytosociological Database and expert knowledge, a database of vascular plant species pools for 88 habitats, representative of the diversity of Czech vegetation, was compiled. This database contains 1820 native species, 249 archaeophytes and 278 neophytes, each assigned to one or more habitats. Besides the data on species occurrence in different habitats, the database contains information on a species’ ecological optimum in the habitat or its dominance. The largest pools of native species were found in rather rare habitats of dry and warm herbaceous or woody habitats at low altitudes, some of which contain > 530 species (maximum of 695 species for thermophilous forest fringes). These were followed by common habitats on mesic soils. The smallest pools of native species were in saline, aquatic and bog habitats ( 350 native species always contained > 5 archaeophytes and > 5 neophytes, and often many more. Two hundred and thirty two native species, 18 archaeophytes and 30 neophytes were identified as potential dominants in at least one habitat. However, potentially dominant species made up less than 3% of the species pool for 78 out of 88 habitats. Larger percentages (up to 14.6%) of potential dominants were included in habitats with small species pools and species-poor stands (e.g., aquatic, saline and mire habitats). The number of habitats in which a species occurred was used as a measure of its ecological range. Most ecological generalists were found among the native species, less among the archaeophytes and least among the neophytes. Out of the 36 species that occur as dominants in three or more habitats, 34 were native (many are grasses), onewas an archaeophyte (Cirsium arvense) and one was a neophyte (Impatiens parviflora).
Rights:
http://creativecommons.org/publicdomain/mark/1.0/