TY - JOUR A1 - Van Kleunen, Mark A1 - Weber, Ewald A1 - Fischer, Markus T1 - A meta-analysis of trait differences between invasive and non-invasive plant species N2 - A major aim in ecology is identifying determinants of invasiveness. We performed a meta-analysis of 117 field or experimental-garden studies that measured pair-wise trait differences of a total of 125 invasive and 196 non-invasive plant species in the invasive range of the invasive species. We tested whether invasiveness is associated with performance-related traits (physiology, leaf-area allocation, shoot allocation, growth rate, size and fitness), and whether such associations depend on type of study and on biogeographical or biological factors. Overall, invasive species had significantly higher values than non-invasive species for all six trait categories. More trait differences were significant for invasive vs. native comparisons than for invasive vs. non-invasive alien comparisons. Moreover, for comparisons between invasive species and native species that themselves are invasive elsewhere, no trait differences were significant. Differences in physiology and growth rate were larger in tropical regions than in temperate regions. Trait differences did not depend on whether the invasive alien species originates from Europe, nor did they depend on the test environment. We conclude that invasive alien species had higher values for those traits related to performance than non-invasive species. This suggests that it might become possible to predict future plant invasions from species traits. Y1 - 2010 UR - http://www3.interscience.wiley.com/journal/118545752/home SN - 1461-023X ER - TY - JOUR A1 - Khuroo, Anzar A. A1 - Reshi, Zafar A. A1 - Malik, Akhtar H. A1 - Weber, Ewald A1 - Rashid, Irfan A1 - Dar, G. H. T1 - Alien flora of India taxonomic composition, invasion status and biogeographic affiliations JF - Biological invasions : unique international journal uniting scientists in the broad field of biological invasions N2 - The wide knowledge gaps in invasion biology research that exist in the developing world are crucial impediments to the scientific management and global policymaking on biological invasions. In an effort to fill such knowledge gaps, we present here an inventory of the alien flora of India, based on systematic reviews and rigorous analyses of research studies (ca. 190) published over the last 120 years (1890-2010 AD), and updated with field records of the last two decades. Currently, the inventory comprises of 1,599 species, belonging to 842 genera in 161 families, and constitutes 8.5% of the total Indian vascular flora. The three most species-rich families are Asteraceae (134 spp.), Papilionaceae (114 spp.) and Poaceae (106 spp.), and the three largest genera are Eucalyptus (25 spp.), Ipomoea (22 spp.), and Senna (21 spp.). The majority of these species (812) have no report of escaping from cultivation. Of the remaining subset of 787 species, which have either escaped from intentional cultivation, or spread after unintentional introduction, casuals are represented by 57 spp., casual/naturalised by 114 spp., naturalised by 257 spp., naturalised/invasive by 134 spp., and invasive by 225 spp. Biogeographically, more than one-third (35%) of the alien flora in India has its native ranges in South America, followed by Asia (21%), Africa (20%), Europe (11%), Australia (8%), North America (4%); and cryptogenic (1%). The inventory is expected to serve as the scientific baseline on plant invasions in India, with implications for conservation of global biodiversity. KW - Biodiversity KW - Biological invasions KW - Alien plants KW - Taxonomy KW - Biogeography KW - India Y1 - 2012 U6 - https://doi.org/10.1007/s10530-011-9981-2 SN - 1387-3547 VL - 14 IS - 1 SP - 99 EP - 113 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Khuroo, Anzar A. A1 - Weber, Ewald A1 - Malik, A. H. A1 - Reshi, Zafar A. A1 - Dar, G. H. T1 - Altitudinal distribution patterns of the native and alien woody flora in Kashmir Himalaya, India JF - Environmental research N2 - Background: Many studies have shown that alien species richness pattern follows that of native species richness patterns along environmental gradients, without taking the specific composition of the two groups into account. Objectives: To compare species richness patterns of native and alien woody plants along an altitudinal gradient in Kashmir Himalaya, India, and to analyse the specific composition, e.g. proportion of life forms. Methods: Analysis of secondary data from published floristic inventories. The gradient (500-4800 m asl) was split into 100 m bands and presence/absence data for each species were obtained, for each band. Results: Species richness of both native and alien species followed a hump-shaped distribution. Alien species richness dropped faster above 2000 m asl than the native did. The ratio of trees to shrubs decreased monotonically along the gradient in native species, but showed a peak at c. 2500 m asl in alien species. Alien species flowered in average earlier than native species. Conclusions: The change of species richness of native and alien species along altitude is similar, but the proportion of life forms is not. Most likely both climatic and socio-economic factors affect alien species richness and its specific composition in the Kashmir Himalaya. KW - Alien species KW - Elevation KW - Floristics KW - Plant invasions KW - Species richness Y1 - 2011 U6 - https://doi.org/10.1016/j.envres.2011.05.006 SN - 0013-9351 VL - 111 IS - 7 SP - 967 EP - 977 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Heinken, Thilo A1 - Weber, Ewald T1 - Consequences of habitat fragmentation for plant species do we know enough? JF - Perspectives in plant ecology, evolution and systematics N2 - Habitat fragmentation is one of the most important causes for the decline of plant species. However, plants differing in phylogeny, habitat requirements and biology are likely to respond differently to habitat fragmentation. We ask whether case studies on the effects of habitat fragmentation conducted so far allow generalizations about its effects on the fitness and genetic diversity of populations of endangered plant species. We compared the characteristics of plant species endangered in Germany whose sensitivity to habitat fragmentation had been studied with those of the endangered species that had not been studied. We found strong discrepancies between the two groups with regard to their taxonomy and traits relevant to their sensitivity to habitat fragmentation. Monocots, graminoids, clonal, abiotically pollinated and self compatible species were underrepresented among the studied species, and most study species were from a few habitat types, in particular grasslands. We conclude that our current knowledge of the effects of habitat fragmentation on plant populations is not sufficient to provide widely applicable guidelines for species management. The selection of species studied so far has been biased toward species from certain habitats and species exhibiting traits that probably make them vulnerable to habitat fragmentation. Future studies should include community-wide approaches in different habitats, e.g. re-visitation studies in which the species pool is assessed at different time intervals, and population-biological studies of species from a wide range of habitats, and of different life forms and growth strategies. A more representative picture of the effects of habitat fragmentation would allow a better assessment of threats and more specific recommendations for optimally managing populations of endangered plants. KW - CSR-strategies KW - Naturally rare species KW - Plant conservation KW - Recently rare species KW - Species traits KW - Taxonomic position Y1 - 2013 U6 - https://doi.org/10.1016/j.ppees.2013.05.003 SN - 1433-8319 VL - 15 IS - 4 SP - 205 EP - 216 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Essl, Franz A1 - Dawson, Wayne A1 - Kreft, Holger A1 - Pergl, Jan A1 - Pysek, Petr A1 - van Kleunen, Mark A1 - Weigelt, Patrick A1 - Mang, Thomas A1 - Dullinger, Stefan A1 - Lenzner, Bernd A1 - Moser, Dietmar A1 - Maurel, Noelie A1 - Seebens, Hanno A1 - Stein, Anke A1 - Weber, Ewald A1 - Chatelain, Cyrille A1 - Inderjit, A1 - Genovesi, Piero A1 - Kartesz, John A1 - Morozova, Olga A1 - Nishino, Misako A1 - Nowak, Pauline M. A1 - Pagad, Shyama A1 - Shu, Wen-sheng A1 - Winter, Marten T1 - Drivers of the relative richness of naturalized and invasive plant species on Earth JF - AoB PLANTS N2 - Biological invasions are a defining feature of the Anthropocene, but the factors that determine the spatially uneven distribution of alien plant species are still poorly understood. Here, we present the first global analysis of the effects of biogeographic factors, the physical environment and socio-economy on the richness of naturalized and invasive alien plants. We used generalized linear mixed-effects models and variation partitioning to disentangle the relative importance of individual factors, and, more broadly, of biogeography, physical environment and socio-economy. As measures of the magnitude of permanent anthropogenic additions to the regional species pool and of species with negative environmental impacts, we calculated the relative richness of naturalized (= RRN) and invasive (= RRI) alien plant species numbers adjusted for the number of native species in 838 terrestrial regions. Socio-economic factors (per-capita gross domestic product (GDP), population density, proportion of agricultural land) were more important in explaining RRI (similar to 50 % of the explained variation) than RRN (similar to 40 %). Warm-temperate and (sub)tropical regions have higher RRN than tropical or cooler regions. We found that socio-economic pressures are more relevant for invasive than for naturalized species richness. The expectation that the southern hemisphere is more invaded than the northern hemisphere was confirmed only for RRN on islands, but not for mainland regions nor for RRI. On average, islands have similar to 6-fold RRN, and >3-fold RRI compared to mainland regions. Eighty-two islands (=26 % of all islands) harbour more naturalized alien than native plants. Our findings challenge the widely held expectation that socio-economic pressures are more relevant for plant naturalization than for invasive plants. To meet international biodiversity targets and halt the detrimental consequences of plant invasions, it is essential to disrupt the connection between socio-economic development and plant invasions by improving pathway management, early detection and rapid response. KW - Alien species richness KW - biogeography KW - invasion stages KW - islands KW - pressures KW - vascular plants Y1 - 2019 U6 - https://doi.org/10.1093/aobpla/plz051 SN - 2041-2851 VL - 11 IS - 5 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - van Kleunen, Mark A1 - Dawson, Wayne A1 - Essl, Franz A1 - Pergl, Jan A1 - Winter, Marten A1 - Weber, Ewald A1 - Kreft, Holger A1 - Weigelt, Patrick A1 - Kartesz, John A1 - Nishino, Misako A1 - Antonova, Liubov A. A1 - Barcelona, Julie F. A1 - Cabezas, Francisco J. A1 - Cardenas, Dairon A1 - Cardenas-Toro, Juliana A1 - Castano, Nicolas A1 - Chacon, Eduardo A1 - Chatelain, Cyrille A1 - Ebel, Aleksandr L. A1 - Figueiredo, Estrela A1 - Fuentes, Nicol A1 - Groom, Quentin J. A1 - Henderson, Lesley A1 - Inderjit, A1 - Kupriyanov, Andrey A1 - Masciadri, Silvana A1 - Meerman, Jan A1 - Morozova, Olga A1 - Moser, Dietmar A1 - Nickrent, Daniel L. A1 - Patzelt, Annette A1 - Pelser, Pieter B. A1 - Baptiste, Maria P. A1 - Poopath, Manop A1 - Schulze, Maria A1 - Seebens, Hanno A1 - Shu, Wen-sheng A1 - Thomas, Jacob A1 - Velayos, Mauricio A1 - Wieringa, Jan J. A1 - Pysek, Petr T1 - Global exchange and accumulation of non-native plants JF - Nature : the international weekly journal of science N2 - All around the globe, humans have greatly altered the abiotic and biotic environment with ever-increasing speed. One defining feature of the Anthropocene epoch(1,2) is the erosion of biogeographical barriers by human-mediated dispersal of species into new regions, where they can naturalize and cause ecological, economic and social damage(3). So far, no comprehensive analysis of the global accumulation and exchange of alien plant species between continents has been performed, primarily because of a lack of data. Here we bridge this knowledge gap by using a unique global database on the occurrences of naturalized alien plant species in 481 mainland and 362 island regions. In total, 13,168 plant species, corresponding to 3.9% of the extant global vascular flora, or approximately the size of the native European flora, have become naturalized somewhere on the globe as a result of human activity. North America has accumulated the largest number of naturalized species, whereas the Pacific Islands show the fastest increase in species numbers with respect to their land area. Continents in the Northern Hemisphere have been the major donors of naturalized alien species to all other continents. Our results quantify for the first time the extent of plant naturalizations worldwide, and illustrate the urgent need for globally integrated efforts to control, manage and understand the spread of alien species. Y1 - 2015 U6 - https://doi.org/10.1038/nature14910 SN - 0028-0836 SN - 1476-4687 VL - 525 IS - 7567 SP - 100 EP - + PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Seebens, Hanno A1 - Essl, Franz A1 - Dawson, Wayne A1 - Fuentes, Nicol A1 - Moser, Dietmar A1 - Pergl, Jan A1 - Pysek, Petr A1 - van Kleunen, Mark A1 - Weber, Ewald A1 - Winter, Marten A1 - Blasius, Bernd T1 - Global trade will accelerate plant invasions in emerging economies under climate change JF - Global change biology N2 - Trade plays a key role in the spread of alien species and has arguably contributed to the recent enormous acceleration of biological invasions, thus homogenizing biotas worldwide. Combining data on 60-year trends of bilateral trade, as well as on biodiversity and climate, we modeled the global spread of plant species among 147 countries. The model results were compared with a recently compiled unique global data set on numbers of naturalized alien vascular plant species representing the most comprehensive collection of naturalized plant distributions currently available. The model identifies major source regions, introduction routes, and hot spots of plant invasions that agree well with observed naturalized plant numbers. In contrast to common knowledge, we show that the 'imperialist dogma,' stating that Europe has been a net exporter of naturalized plants since colonial times, does not hold for the past 60 years, when more naturalized plants were being imported to than exported from Europe. Our results highlight that the current distribution of naturalized plants is best predicted by socioeconomic activities 20 years ago. We took advantage of the observed time lag and used trade developments until recent times to predict naturalized plant trajectories for the next two decades. This shows that particularly strong increases in naturalized plant numbers are expected in the next 20 years for emerging economies in megadiverse regions. The interaction with predicted future climate change will increase invasions in northern temperate countries and reduce them in tropical and (sub) tropical regions, yet not by enough to cancel out the trade-related increase. KW - alien vascular plants KW - bioinvasion KW - climate warming KW - global spread KW - imperialist dogma KW - model KW - network of plant invasion Y1 - 2015 U6 - https://doi.org/10.1111/gcb.13021 SN - 1354-1013 SN - 1365-2486 VL - 21 IS - 11 SP - 4128 EP - 4140 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Pyšek, Petr A1 - Pergl, Jan A1 - Essl, Franz A1 - Lenzner, Bernd A1 - Dawson, Wayne A1 - Kreft, Holger A1 - Weigelt, Patrick A1 - Winter, Marten A1 - Kartesz, John A1 - Nishino, Misako A1 - Antonova, Liubov A. A1 - Barcelona, Julie F. A1 - Cabezas, Francisco José A1 - Cárdenas López, Dairon A1 - Cárdenas-Toro, Juliana A1 - Castańo, Nicolás A1 - Chacón, Eduardo A1 - Chatelain, Cyrille A1 - Dullinger, Stefan A1 - Ebel, Aleksandr L. A1 - Figueiredo, Estrela A1 - Fuentes, Nicol A1 - Genovesi, Piero A1 - Groom, Quentin J. A1 - Henderson, Lesley A1 - Inderjit, A1 - Kupriyanov, Andrey A1 - Masciadri, Silvana A1 - Maurel, Noëlie A1 - Meerman, Jan A1 - Morozova, Olʹga V. A1 - Moser, Dietmar A1 - Nickrent, Daniel A1 - Nowak, Pauline M. A1 - Pagad, Shyama A1 - Patzelt, Annette A1 - Pelser, Pieter B. A1 - Seebens, Hanno A1 - Shu, Wen-sheng A1 - Thomas, Jacob A1 - Velayos, Mauricio A1 - Weber, Ewald A1 - Wieringa, Jan J. A1 - Baptiste, Maria P. A1 - Kleunen, Mark van T1 - Naturalized alien flora of the world T1 - Naturalizovaná nepůvodní flóra světa BT - species diversity, taxonomic and phylogenetic patterns, geographic distribution and global hotspots of plant invasion BT - druhová diverzita, taxonomické a fylogenetické složení, geografické zákonitosti a globální ohniska rostlinných invazí JF - Preslia : the journal of the Czech Botanical Society N2 - Using the recently built Global Naturalized Alien Flora (GloNAF) database, containing data on the distribution of naturalized alien plants in 483 mainland and 361 island regions of the world, we describe patterns in diversity and geographic distribution of naturalized and invasive plant species, taxonomic, phylogenetic and life-history structure of the global naturalized flora as well as levels of naturalization and their determinants. The mainland regions with the highest numbers of naturalized aliens are some Australian states (with New South Wales being the richest on this continent) and several North American regions (of which California with 1753 naturalized plant species represents the world’s richest region in terms of naturalized alien vascular plants). England, Japan, New Zealand and the Hawaiian archipelago harbour most naturalized plants among islands or island groups. These regions also form the main hotspots of the regional levels of naturalization, measured as the percentage of naturalized aliens in the total flora of the region. Such hotspots of relative naturalized species richness appear on both the western and eastern coasts of North America, in north-western Europe, South Africa, south-eastern Australia, New Zealand, and India. High levels of island invasions by naturalized plants are concentrated in the Pacific, but also occur on individual islands across all oceans. The numbers of naturalized species are closely correlated with those of native species, with a stronger correlation and steeper increase for islands than mainland regions, indicating a greater vulnerability of islands to invasion by species that become successfully naturalized. South Africa, India, California, Cuba, Florida, Queensland and Japan have the highest numbers of invasive species. Regions in temperate and tropical zonobiomes harbour in total 9036 and 6774 naturalized species, respectively, followed by 3280 species naturalized in the Mediterranean zonobiome, 3057 in the subtropical zonobiome and 321 in the Arctic. The New World is richer in naturalized alien plants, with 9905 species compared to 7923 recorded in the Old World. While isolation is the key factor driving the level of naturalization on islands, zonobiomes differing in climatic regimes, and socioeconomy represented by per capita GDP, are central for mainland regions. The 11 most widely distributed species each occur in regions covering about one third of the globe or more in terms of the number of regions where they are naturalized and at least 35% of the Earth’s land surface in terms of those regions’ areas, with the most widely distributed species Sonchus oleraceus occuring in 48% of the regions that cover 42% of the world area. Other widely distributed species are Ricinus communis, Oxalis corniculata, Portulaca oleracea, Eleusine indica, Chenopodium album, Capsella bursa-pastoris, Stellaria media, Bidens pilosa, Datura stramonium and Echinochloa crus-galli. Using the occurrence as invasive rather than only naturalized yields a different ranking, with Lantana camara (120 regions out of 349 for which data on invasive status are known), Calotropis procera (118), Eichhornia crassipes (113), Sonchus oleraceus (108) and Leucaena leucocephala (103) on top. As to the life-history spectra, islands harbour more naturalized woody species (34.4%) thanmainland regions (29.5%), and fewer annual herbs (18.7% compared to 22.3%). Ranking families by their absolute numbers of naturalized species reveals that Compositae (1343 species), Poaceae (1267) and Leguminosae (1189) contribute most to the global naturalized alien flora. Some families are disproportionally represented by naturalized aliens on islands (Arecaceae, Araceae, Acanthaceae, Amaryllidaceae, Asparagaceae, Convolvulaceae, Rubiaceae, Malvaceae), and much fewer so on mainland (e.g. Brassicaceae, Caryophyllaceae, Boraginaceae). Relating the numbers of naturalized species in a family to its total global richness shows that some of the large species-rich families are over-represented among naturalized aliens (e.g. Poaceae, Leguminosae, Rosaceae, Amaranthaceae, Pinaceae), some under-represented (e.g. Euphorbiaceae, Rubiaceae), whereas the one richest in naturalized species, Compositae, reaches a value expected from its global species richness. Significant phylogenetic signal indicates that families with an increased potential of their species to naturalize are not distributed randomly on the evolutionary tree. Solanum (112 species), Euphorbia (108) and Carex (106) are the genera richest in terms of naturalized species; over-represented on islands are Cotoneaster, Juncus, Eucalyptus, Salix, Hypericum, Geranium and Persicaria, while those relatively richer in naturalized species on the mainland are Atriplex, Opuntia, Oenothera, Artemisia, Vicia, Galium and Rosa. The data presented in this paper also point to where information is lacking and set priorities for future data collection. The GloNAF database has potential for designing concerted action to fill such data gaps, and provide a basis for allocating resources most efficiently towards better understanding and management of plant invasions worldwide. KW - alien species KW - distribution KW - Global Naturalized Alien Flora (GloNAF) database KW - invasive species KW - islands KW - life history KW - mainland KW - naturalized species KW - phylogeny KW - plant invasion KW - regional floras KW - species richness KW - taxonomy KW - zonobiome Y1 - 2017 U6 - https://doi.org/10.23855/preslia.2017.203 SN - 0032-7786 VL - 89 IS - 3 SP - 203 EP - 274 PB - Czech Botanical Soc. CY - Praha ER - TY - JOUR A1 - Dellinger, Agnes S. A1 - Essl, Franz A1 - Hojsgaard, Diego A1 - Kirchheimer, Bernhard A1 - Klatt, Simone A1 - Dawson, Wayne A1 - Pergl, Jan A1 - Pysek, Petr A1 - van Kleunen, Mark A1 - Weber, Ewald A1 - Winter, Marten A1 - Hoerandl, Elvira A1 - Dullinger, Stefan T1 - Niche dynamics of alien species do not differ among sexual and apomictic flowering plants JF - New phytologist : international journal of plant science N2 - We compiled global occurrence data sets of 13 congeneric sexual and apomictic species pairs, and used principal components analysis (PCA) and kernel smoothers to compare changes in climatic niche optima, breadths and unfilling/expansion between native and alien ranges. Niche change metrics were compared between sexual and apomictic species. All 26 species showed changes in niche optima and/or breadth and 14 species significantly expanded their climatic niches. However, we found no effect of the reproductive system on niche dynamics. Instead, species with narrower native niches showed higher rates of niche expansion in the alien ranges. Our results suggest that niche shifts are frequent in plant invasions but evolutionary potential may not be of major importance for such shifts. Niche dynamics rather appear to be driven by changes of the realized niche without adaptive change of the fundamental climatic niche. KW - adaptation KW - asexual reproduction KW - niche shifts KW - plant invasion KW - reproductive system KW - species distribution modelling Y1 - 2016 U6 - https://doi.org/10.1111/nph.13694 SN - 0028-646X SN - 1469-8137 VL - 209 SP - 1313 EP - 1323 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Cochard, Roland A1 - Edwards, Peter J. A1 - Weber, Ewald T1 - Post-ranching tree-grass interactions in secondary Acacia zanzibarica woodlands in coastal Tanzania - an experimental study JF - Applied vegetation science : official organ of the International Association for Vegetation Science N2 - Questions: We studied a humid savanna rangeland., abandoned in 2000, where intensive cattle grazing had led to widespread encroachment by Acacia zanzibarica. We asked whether the acacia trees were able to regenerate in the absence of domesJic livestock, either beneath acacia canopies or in artificial clearings. Location: Tropical coastal Tanzania (former Mkwaja Ranch, now in Saadani National Park). Methods: We set out a total of 48 plots on four sites in November 2001, and assigned them to three treatments: trees felled (FN), trees felled and the stumps poisoned (FP) with Triclopyr, and no intervention (controls, NN). We analysed soils of plots for texture and nutrients. In two wet (July 2002 and 2003) and one dry (February 2003) seasons we assessed grass and tree leaf biomass and transpiration rates, and counted acacia seedlings and resprouts. The effects of treatments (controlled for site and other co-variables) on grass growth and acacia rectaiitment were determined statistically using general linear models (GLM). Results: Acacia leaves had a much higher stomatal conductance than grasses, with the consequence that total evapotranspiration in woodland was higher than in clearings. In the wet seasons, grass biomass and seedling densities were significantly higher in clearings than in control plots, which we attributed to more.favourable moisture conditions, In the dry season, by contrast, we found no differences, and all seedlings had died. On FN plots, 71% of stumps, and on FP plots, 11% resprouted (coppicing), but only a quarter of these shoots survived until July 2003. Root suckering occurred spontaneously at low densities. No root suckers or resprouts grew beyond the grass layer. Conclusions: Acacia woodlands do not regenerate in the absence of cattle grazing, and tree cutting in combination with appropriate fire management could potentially accelerate re-establishment of open grassland. However, regeneration might occur in the future due to the increasing wildlife populations within the new national park. KW - Bush encroachment KW - Clearing formation KW - Grass flush KW - Savanna rangeland dynamics KW - Sprouting KW - Tree recruitment Y1 - 2015 U6 - https://doi.org/10.1111/avsc.12134 SN - 1402-2001 SN - 1654-109X VL - 18 IS - 2 SP - 297 EP - 310 PB - Wiley-Blackwell CY - Hoboken ER -