Browsing by Author "Dawson, Wayne"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Data descriptor : Pacific introduced flora (PaciFLora)
    (Pensoft, 2021-07-20) Wohlwend, Michael Rudolf; Craven, Dylan; Weigelt, Patrick; Seebens, Hanno; Winter, Marten; Kreft, Holger; Dawson, Wayne; Essl, Franz; Van Kleunen, Marl; Pergl, Jan; Pysek, Petr; Space, James; Thomas, Philip; Knight, Tiffany
    ENGLISH ABSTRACT: The Pacific region has the highest density of naturalized plant species worldwide, which makes it an important area for research on the ecology, evolution and biogeography of biological invasions. While different data sources on naturalized plant species exist for the Pacific, there is no taxonomically and spatially harmonized database available for different subsets of species and islands. A comprehensive, accessible database containing the distribution of naturalized vascular plant species in the Pacific will enable new basic and applied research for researchers and will be an important information source for practitioners working in the region.Here, we present PacIFlora, an updated and taxonomically standardized list of naturalized species, their unified nativeness, cultivation and invasiveness status, and their distribution across the Pacific Ocean, including harmonized location denommination. This list is based on the two largest databases on naturalized plants for the region, specifically the Pacific Island Ecosystems at Risk (PIER) and the Global Naturalized Alien Flora (GloNAF) databases. We provide an outlook for how this database can contribute to numerous research questions and conservation efforts.
  • Thumbnail Image
    Item
    Naturalization of European plants on other continents : the role of donor habitats
    (National Academy of Sciences, 2019) Kalusova, Veronika; Chytry, Milan; Van Kleunen, Mark; Mucina, Ladislav; Dawson, Wayne; Essl, Franz; Kreft, Holger; Pergl, Jan; Weigelt, Patrick; Winter, Marten; Pysek, Petr
    The success of European plant species as aliens worldwide is thought to reflect their association with human-disturbed environments. However, an explicit test including all human-made, seminatural and natural habitat types of Europe, and their contributions as donor habitats of naturalized species to the rest of the globe, has been missing. Here we combine two databases, the European Vegetation Checklist and the Global Naturalized Alien Flora, to assess how human influence in European habitats affects the probability of naturalization of their plant species on other continents. A total of 9,875 native European vascular plant species were assigned to 39 European habitat types; of these, 2,550 species have become naturalized somewhere in the world. Species that occur in both human-made habitats and seminatural or natural habitats in Europe have the highest probability of naturalization (64.7% and 64.5% of them have naturalized). Species associated only with human-made or seminatural habitats still have a significantly higher probability of becoming naturalized (41.7% and 28.6%, respectively) than species confined to natural habitats (19.4%). Species associated with arable land and human settlements were recorded as naturalized in the largest number of regions worldwide. Our findings highlight that plant species’ association with native-range habitats disturbed by human activities, combined with broad habitat range, play an important role in shaping global patterns of plant invasions.
  • Thumbnail Image
    Item
    Phylogenetic structure of alien plant species pools from European donor habitats
    (John Wiley & Sons Ltd., 2021) Kalusova, Veronika; Cubino, Josep Padulles; Fristoe, Trevor S.; Chytry, Milan; Van Kleunen, Mark; Dawson, Wayne; Essl, Franz; Kreft, Holger; Mucina, Ladislav; Pergl, Jan; Pysek, Petr; Weigelt, Patrick; Winter, Marten; Lososova, Zdenka
    Aim: Many plant species native to Europe have naturalized worldwide. We tested whether the phylogenetic structure of the species pools of European habitats is related to the proportion of species from each habitat that has naturalized outside Europe (habitat’s donor role) and whether the donated species are more phylogenetically related to each other than expected by chance. Location: Europe (native range), the rest of the world (invaded range). Time period: Last c. 100 years. Major taxa studied: Angiospermae. Methods: We selected 33 habitats in Europe and analysed their species pools, including 9,636 plant species, of which 2,293 have naturalized outside Europe. We assessed the phylogenetic structure of each habitat as the difference between the observed and expected mean pairwise phylogenetic distance (MPD) for (a) the whole species pool and (b) subgroups of species that have naturalized outside Europe and those that have not. We used generalized linear models to test for the effects of the phylogenetic structure and the level of human influence on the habitat’s donor role.
  • Thumbnail Image
    Item
    Projecting the continental accumulation of alien species through to 2050
    (John Wiley & Sons, 2020) Seebens, Hanno; Bacher, Sven; Blackburn, Tim M.; Capinha, Cesar; Dawson, Wayne; Dullinger, Stefan; Genovesi, Piero; Hulme, Philip E.; Van Kleunen, Mark; Kuhn, Ingolf; Jeschke, Jonathan M.; Lenzner, Bernd; Liebhold, Andrew M.; Pattison, Zarah; Pergl, Jan; Pysek, Petr; Winter, Marten; Essl, Franz
    Biological invasions have steadily increased over recent centuries. However, we still lack a clear expectation about future trends in alien species numbers. In particular, we do not know whether alien species will continue to accumulate in regional floras and faunas, or whether the pace of accumulation will decrease due to the depletion of native source pools. Here, we apply a new model to simulate future numbers of alien species based on estimated sizes of source pools and dynamics of historical invasions, assuming a continuation of processes in the future as observed in the past (a business‐as‐usual scenario). We first validated performance of different model versions by conducting a back‐casting approach, therefore fitting the model to alien species numbers until 1950 and validating predictions on trends from 1950 to 2005. In a second step, we selected the best performing model that provided the most robust predictions to project trajectories of alien species numbers until 2050. Altogether, this resulted in 3,790 stochastic simulation runs for 38 taxon–continent combinations. We provide the first quantitative projections of future trajectories of alien species numbers for seven major taxonomic groups in eight continents, accounting for variation in sampling intensity and uncertainty in projections. Overall, established alien species numbers per continent were predicted to increase from 2005 to 2050 by 36%. Particularly, strong increases were projected for Europe in absolute (+2,543 ± 237 alien species) and relative terms, followed by Temperate Asia (+1,597 ± 197), Northern America (1,484 ± 74) and Southern America (1,391 ± 258). Among individual taxonomic groups, especially strong increases were projected for invertebrates globally. Declining (but still positive) rates were projected only for Australasia. Our projections provide a first baseline for the assessment of future developments of biological invasions, which will help to inform policies to contain the spread of alien species.
  • Thumbnail Image
    Item
    Role of diversification rates and evolutionary history as a driver of plant naturalization success
    (Wiley, 2020) Lenzner, Bernd; Magallon, Susana; Dawson, Wayne; Kreft, Holger; Konig, Christian; Pergl, Jan; Pysek, Petr; Weigelt, Patrick; Van Kleunen, Mark; Winter, Marten; Dullinger, Stefan; Essl, Franz
    ENGLISH ABSTRACT: Human introductions of species beyond their natural ranges and their subsequent establishment are defining features of global environmental change. However, naturalized plants are not uniformly distributed across phylogenetic lineages, with some families contributing disproportionately more to the global alien species pool than others. Additionally, lineages differ in diversification rates, and high diversification rates have been associated with characteristics that increase species naturalization success. Here, we investigate the role of diversification rates in explaining the naturalization success of angiosperm plant families. We use five global data sets that include native and alien plant species distribution, horticultural use of plants, and a time-calibrated angiosperm phylogeny. Using phylogenetic generalized linear mixed models, we analysed the effect of diversification rate, different geographical range measures, and horticultural use on the naturalization success of plant families. We show that a family's naturalization success is positively associated with its evolutionary history, native range size, and economic use. Investigating interactive effects of these predictors shows that native range size and geographic distribution additionally affect naturalization success. High diversification rates and large ranges increase naturalization success, especially of temperate families. We suggest this may result from lower ecological specialization in temperate families with large ranges, compared with tropical families with smaller ranges.
  • Thumbnail Image
    Item
    Scientists’ warning on invasive alien species
    (Wiley, 2019) Pysek, Petr; Hulme, Philip E.; Simberloff, Dan; Bacher, Sven; Blackburn, Tim M.; Carlton, James T.; Dawson, Wayne; Essl, Franz; Foxcroft, Llewellyn C.; Genovesi, Piero; Jeschke, Jonathan M.; Kühn, Ingolf; Liebhold, Andrew M.; Mandrak, Nicholas E.; Meyerson, Laura A.; Pauchard, Aníbal; Pergl, Jan; Roy, Helen E.; Seebens, Hanno; Van Kleunen, Mark; Vila, Montserrat; Wingfield, Michael J.; Richardson, David M.
    Biological invasions are a global consequence of an increasingly connected world and the rise in human population size. The numbers of invasive alien species – the subset of alien species that spread widely in areas where they are not native, affecting the environment or human livelihoods – are increasing. Synergies with other global changes are exacerbating current invasions and facilitating new ones, thereby escalating the extent and impacts of invaders. Invasions have complex and often immense long-term direct and indirect impacts. In many cases, such impacts become apparent or problematic only when invaders are well established and have large ranges. Invasive alien species break down biogeographic realms, affect native species richness and abundance, increase the risk of native species extinction, affect the genetic composition of native populations, change native animal behaviour, alter phylogenetic diversity across communities, and modify trophic networks. Many invasive alien species also change ecosystem functioning and the delivery of ecosystem services by altering nutrient and contaminant cycling, hydrology, habitat structure, and disturbance regimes. These biodiversity and ecosystem impacts are accelerating and will increase further in the future. Scientific evidence has identified policy strategies to reduce future invasions, but these strategies are often insufficiently implemented. For some nations, notably Australia and New Zealand, biosecurity has become a national priority. There have been long-term successes, such as eradication of rats and cats on increasingly large islands and biological control of weeds across continental areas. However, in many countries, invasions receive little attention. Improved international cooperation is crucial to reduce the impacts of invasive alien species on biodiversity, ecosystem services, and human livelihoods. Countries can strengthen their biosecurity regulations to implement and enforce more effective management strategies that should also address other global changes that interact with invasions.
  • Thumbnail Image
    Item
    Source pools and disharmony of the world's island floras
    (Nordic Society Oikos, 2020) Konig, Christian; Weigelt, Patrick; Taylor, Amanda; Stein, Anke; Dawson, Wayne; Essl, Franz; Pergl, Jan; Pysek, Petr; Van Kleunen, Mark; Winter, Marten; Chatelain, Cyrille; Wieringa, Jan J.; Krestov, Pavel; Kreft, Holger
    Island disharmony refers to the biased representation of higher taxa on islands compared to their mainland source regions and represents a central concept in island biology. Here, we develop a generalizable framework for approximating these source regions and conduct the first global assessment of island disharmony and its underlying drivers. We compiled vascular plant species lists for 178 oceanic islands and 735 mainland regions. Using mainland data only, we modelled species turnover as a function of environmental and geographic distance and predicted the proportion of shared species between each island and mainland region. We then quantified the over- or under-representation of families on individual islands (representational disharmony) by contrasting the observed number of species against a null model of random colonization from the mainland source pool, and analysed the effects of six family-level functional traits on the resulting measure. Furthermore, we aggregated the values of representational disharmony per island to characterize overall taxonomic bias of a given flora (compositional disharmony), and analysed this second measure as a function of four island biogeographical variables. Our results indicate considerable variation in representational disharmony both within and among plant families. Examples of generally over-represented families include Urticaceae, Convolvulaceae and almost all pteridophyte families. Other families such as Asteraceae and Orchidaceae were generally under-represented, with local peaks of over-representation in known radiation hotspots. Abiotic pollination and a lack of dispersal specialization were most strongly associated with an insular over-representation of families, whereas other family-level traits showed minor effects. With respect to compositional disharmony, large, high-elevation islands tended to have the most disharmonic floras. Our results provide important insights into the taxon- and island-specific drivers of disharmony. The proposed framework allows overcoming the limitations of previous approaches and provides a quantitative basis for incorporating functional and phylogenetic approaches into future studies of island disharmony.