Browsing by Author "Lenzner, Bernd"

Now showing 1 - 5 of 5
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    The Convention on Biological Diversity (CBD)’s Post-2020 target on invasive alien species – what should it include and how should it be monitored?
    (2020-10-15) Essl, Franz; Latombe, Guillaume; Lenzner, Bernd; Pagad, Shyama; Seebens, Hanno; Smith, Kevin; Wilson, John R. U.; Genovesi, Piero
    ENGLISH ABSTRACT: The year 2020 and the next few years are critical for the development of the global biodiversity policy agenda until the mid-21st century, with countries agreeing to a Post-2020 Global Biodiversity Framework under the Convention on Biological Diversity (CBD). Reducing the substantial and still rising impacts of invasive alien species (IAS) on biodiversity will be essential if we are to meet the 2050 Vision where biodiversity is valued, conserved, and restored. A tentative target has been developed by the IUCN Invasive Species Specialist Group (ISSG), and formally submitted to the CBD for consideration in the discussion on the Post-2020 targets. Here, we present properties of this proposal that we regard as essential for an effective Post-2020 Framework. The target should explicitly consider the three main components of biological invasions, i.e. (i) pathways, (ii) species, and (iii) sites; the target should also be (iv) quantitative, (v) supplemented by a set of indicators that can be applied to track progress, and (vi) evaluated at medium- (2030) and long-term (2050) time horizons. We also present a proposed set of indicators to track progress. These properties and indicators are based on the increasing scientific understanding of biological invasions and effectiveness of responses. Achieving an ambitious action-oriented target so that the 2050 Vision can be achieved will require substantial effort and resources, and the cooperation of a wide range of stakeholders.
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    Drivers of future alien species impacts: an expert-based assessment
    (Wiley, 2020) Essl, Franz; Lenzner, Bernd; Bacher, Sven; Bailey, Sarah; Hui, Cang; Kuhn, Ingolf; Pysek, Petr; Richardson, David M.
    ENGLISH ABSTRACT: Understanding the likely future impacts of biological invasions is crucial yet highly challenging given the multiple relevant environmental, socio-economic and societal contexts and drivers. In the absence of quantitative models, methods based on expert knowledge are the best option for assessing future invasion trajectories. Here, we present an expert assessment of the drivers of potential alien species impacts under contrasting scenarios and socioecological contexts through the mid-21st century. Based on responses from 36 experts in biological invasions, moderate (20%–30%) increases in invasions, compared to the current conditions, are expected to cause major impacts on biodiversity in most socioecological contexts. Three main drivers of biological invasions—transport, climate change and socio-economic change—were predicted to significantly affect future impacts of alien species on biodiversity even under a best-case scenario. Other drivers (e.g. human demography and migration in tropical and subtropical regions) were also of high importance in specific global contexts (e.g. for individual taxonomic groups or biomes). We show that some best-case scenarios can substantially reduce potential future impacts of biological invasions. However, rapid and comprehensive actions are necessary to use this potential and achieve the goals of the Post-2020 Framework of the Convention on Biological Diversity.
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    Invasion costs, impacts, and human agency : response to Sagoff 2020
    (Wiley, 2020) Cuthbert, Ross N.; Bacher, Sven; Blackburn, Tim M.; Briski, Elizabeta; Diagne, Christophe; Dick, Jaimie T. A.; Essl, Franz; Genovesi, Piero; Haubrock, Phillip J.; Latombe, Guillaume; Lenzner, Bernd; Meinard, Yves; Pauchard, Anibal; Pysek, Petr; Ricciardi, Anthony; Richardson, David M.; Russell, James C.; Simberloff, Daniel; Courchamp, Franck
    Article impact statement: In an era of profound biodiversity crisis, invasion costs, invader impacts, and human agency should not be dismissed.
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    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.
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    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.