Contrasting patterns in the invasions of European terrestrial and freshwater habitats by alien plants, insects and vertebrates

Abstract

Aim To provide the first comparative overview on the current numbers of alien species that invade representative European terrestrial and freshwater habitats for a range of taxonomic groups. Location Europe.Methods Numbers of naturalized alien species of plants, insects, herptiles, birds and mammals occurring in 10 habitats defined according to the European Nature Information System (EUNIS) were obtained from 115 regional data sets. Only species introduced after ad 1500 were considered. Data were analysed by ANCOVA and regression trees to assess whether differences exist among taxonomic groups in terms of their habitat affinity, and whether the pattern of occurrence of alien species in European habitats interacts with macroecological factors such as insularity, latitude or area. ResultsThe highest numbers of alien plant and insect species were found in human-made, urban or cultivated habitats; if controlled for habitat area in the region, wetland and riparian habitats appeared to support relatively high numbers of alien plant species too. Invasions by vertebrates were more evenly distributed among habitats, with aquatic and riparian, woodland and cultivated land most invaded. Mires, bogs and fens, grassland, heathland and scrub were generally less invaded. Habitat and taxonomic group explained most variation in the proportions of alien species occurring in individual habitats related to the total number of alien species in a region, and the basic pattern determined by these factors was fine-tuned by geographical variables, namely by the mainland-island contrast and latitude, and differed among taxonomic groups.Main conclusions There are two ecologically distinct groups of alien species (plants and insects versus vertebrates) with strikingly different habitat affinities. Invasions by these two contrasting groups are complementary in terms of habitat use, which makes an overall assessment of habitat invasions in Europe possible. Since numbers of naturalized species in habitats are correlated among taxa within these two groups, the data collected for one group of vertebrates, for example, could be used to estimate the habitat-specific numbers of alien species for other vertebrate groups with reasonable precision, and the same holds true for insects and plants.

Invasive flora within urban railway areas: a case study from Lublin (Poland) and Lviv (Ukraine)

“…Presumably, a disparity in the gradient of transport intensity (higher at Lviv than at Lublin) or intercity inhabitant disparities (population -2.3 persons per 1 km 2 in Lublin and 4.0 persons per 1 km 2 in Lviv) could explain the considerable discrepancy in the invasive flora between railway systems in the two cities studied. As documented for Europe [26], human transport intensity and a high population size can tend to eliminate native species via extreme human disturbance. Moreover, human mobility in urban areas is suggested to be a primary predictor of invasion intensity [9].…”

“…These physical conditions also directly determine the environment for establishment and survival (reproductive success, seedling recruitment, growth) of plant species outside their distributional range [25,26]. In the last decade, many studies have discussed the potential impact of climate change on the risk of plant invasions [27,28].…”

Changes in Vascular Flora of the Rzeszow Reservoir after 20 Years (SE Poland)

“…Watersides are particularly vulnerable to the invasion of alien species because of disturbances of the littoral zone of river banks [3,69,73]. Research in the European Union indicates that invasions by alien species are observed on anthropogenic, urban, waterlogged, and freshwater habitats [34], causing remarkable environmental and economic effects [68]. In the process of synanthropization of flora, an important role is played by apophytization, which is associated with the ability of the large group of native species to colonize habitats strongly disturbed by human activity.…”

“…River valleys play a role of ecological corridors [3,18,[25][26][27] and are refuges of biodiversity [3,8,21,28]. Sites located along rivers are also exceptionally vulnerable to alien species invasion [18,[29][30][31][32][33][34][35][36]. Artificial water bodies are similar in this respect, and various ecosystems affect them [8,24,37].…”

Anisops sardeus (Heteroptera): A new expansive species in Central Europe

“…However, aquatic insects are seldom recognized as expansive species (Kenis et al 2007;Pyšek et al 2010). Of the entirely aquatic orders of insects only the Odonata are noted as regular invaders (de Moor 1992).…”