Browsing by Author "Pagad, S."
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- ItemClassifying the introduction pathways of alien species: are we moving in the right direction?(2020) Faulkner, K.T.; Hulme, P.E.; Pagad, S.; Wilson, J.R.U.; Robertson, M.P.Alien species are introduced to new regions in many different ways and for different purposes. A number of frameworks have been developed to group such pathways of introduction into discrete categories in order to improve our understanding of biological invasions, provide information for interventions that aim to prevent introductions, enable reporting to national and international organisations and facilitate the prediction of threats. The introduction pathway classification framework proposed by the Convention on Biological Diversity (CBD) as a global standard is comprised of six main categories and 44 sub-categories. However, issues have arisen with its implementation. In this position paper, we outline five desirable properties of an introduction pathway classification framework – it should be compatible (i.e. the level of detail of the categories is similar to that of the available data), actionable (i.e. categories link to specific interventions), general (i.e. categories are applicable across the contexts that are of interest (e.g. taxa, habitats and regions)), equivalent (i.e. categories are equivalent in their level of detail) and distinct (i.e. categories are discrete and easily distinguished) – termed the CAGED properties. The six main categories of the CBD framework have all of the CAGED properties, but the detailed sub-categories have few. Therefore, while the framework has been proposed by the CBD as a global standard and efforts have been made to put it into practice, we argue that there is room for improvement. We conclude by presenting scenarios for how the issues identified could be addressed, noting that a hybrid model might be most appropriate.
- ItemThe Convention on Biological Diversity (CBD)’s Post-2020 target on invasive alien species – what should it include and how should it be monitored?(2020) Essl, F.; Latombe, G.; Lenzner, B.; Pagad, S.; Seebens, H.; Smith, K.; Wilson, J.R.U.; Genovesi, P.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.
- ItemCrossing frontiers in tackling pathways of biological invasions(Oxford University Press, 2015) Essl, F.; Bacher, S.; Blackburn, T.M.; Booy, O.; Brundu, G.; Brunel, S.; Cardoso, A.C.; Eschen, R.; Gallardo, B.; Galil, B.; Garcia-Berthou, E.; Genovesi, P.; Groom, Q.; Harrower, C.; Hulme, P.E.; Katsanevakis, S.; Kenis, M.; Kuhn, I.; Kumschick, S.; Martinou, A.F.; Nentwig, W.; O'Flynn, C.; Pagad, S.; Pergl, J.; Pysek, P.; Rabitsch, W.; Richardson, D.M.; Roques, A.; Roy, H.E.; Scalera, R.; Schindler, S.; Seebens, H.; Vanderhoeven, S.; Vila, M.; Wilson, J.R.U.; Zenetos, A.; Jeschke, J.M.Substantial progress has been made in understanding how pathways underlie and mediate biological invasions. However, key features of their role in invasions remain poorly understood, available knowledge is widely scattered, and major frontiers in research and management are insufficiently characterized. We review the state of the art, highlight recent advances, identify pitfalls and constraints, and discuss major challenges in four broad fields of pathway research and management: pathway classification, application of pathway information, management response, and management impact. We present approaches to describe and quantify pathway attributes (e.g., spatiotemporal changes, proxies of introduction effort, environmental and socioeconomic contexts) and how they interact with species traits and regional characteristics. We also provide recommendations for a research agenda with particular focus on emerging (or neglected) research questions and present new analytical tools in the context of pathway research and management.
- ItemDrivers of the relative richness of naturalized and invasive plant species on Earth(2019) Essl, F.; Dawson, W; Kreft, H.; Pergl, J.; Pyšek, P.; Van Kleunen, M.; Weigelt, P.; Mang, T.; Dullinger, S.; Lenzner, B.; Moser, D.; Maurel, N.; Seebens, H.; Stein, A.; Weber, E.; Chatelain, C.; Inderjit; Genovesi, P.; Kartesz, J.; Morozova, O.; Nishino, M.; Nowak, P.; Pagad, S.; Shu, W.-S.; Winter, M.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 (~50 % of the explained variation) than RRN (~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 ~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.
- ItemNo saturation in the accumulation of alien species worldwide(Nature Research (part of Springer Nature), 2017) Seebens, Hanno; Blackburn, T. M.; Dyer, E. E.; Genovesi, P.; Hulme, P. E.; Jeschke, J. M.; Pagad, S.; Pysek, P.; Winter, M.; Arianoutsou, M.; Bacher, S.; Blasius, B.; Brundu, G.; Capinha, G.; Celesti-Grapow, L.; Dawson, W.; Dullinger, S.; Fuentes, N.; Jager, H.; Kartesz, J.; Kenis, M.; Kreft, H.; Kuhn, I; Lenzner, B.; Liebhold, A.; Mosena, A.; Moser, D.; Nishino, M.; Pearman, D.; Pergl, J.; Rabitsch, W.; Rojas-Sandoval, J.; Roques, A.; Rorke, S.; Rossinelli, S.; Roy, H. E.; Scalera, R.; Schindler, S.; Stajerova, K.; Tokarska-Guzik, B.; Van Kleunen, M.; Walker, K.; Weigelt, P.; Yamanaka, T.; Essl, F.Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.
- ItemA workflow for standardising and integrating alien species distribution data(2020) Seebens, H.; Clarke, D.A.; Groom, Q.; Wilson, J.R.U.; García-Berthou, E.; Kühn, I.; Roigé, M.; Pagad, S.; Essl, F.; Vicente, J.; Winter, M.; McGeoch, M.Biodiversity data are being collected at unprecedented rates. Such data often have significant value for purposes beyond the initial reason for which they were collected, particularly when they are combined and collated with other data sources. In the field of invasion ecology, however, integrating data represents a major challenge due to the notorious lack of standardisation of terminologies and categorisations, and the application of deviating concepts of biological invasions. Here, we introduce the SInAS workflow, short for Standardising and Integrating Alien Species data. The SInAS workflow standardises terminologies following Darwin Core, location names using a proposed translation table, taxon names based on the GBIF backbone taxonomy, and dates of first records based on a set of predefined rules. The output of the SInAS workflow provides various entry points that can be used both to improve coherence among the databases and to check and correct the original data. The workflow is flexible and can be easily adapted and extended to the needs of different users. We illustrate the workflow using a case-study integrating five widely used global databases of information on biological invasions. The comparison of the standardised databases revealed a surprisingly low degree of overlap, which indicates that the amount of data may currently not be fully exploited in the original databases. We highly recommend the use and development of publicly available workflows to ensure that the integration of databases is reproducible and transparent. Workflows, such as SInAS, ultimately increase trust in data, study results, and conclusions.