Browsing by Author "Kühn, I."
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- ItemA conceptual framework for range-expanding species that track human-induced environmental change(2019) Essl, F.; Dullinger, S.; Genovesi, P.; Hulme, P.E.; Jeschke, J.M.; Katsanevakis, S.; Kühn, I.; Lenzner, B.; Pauchard, A.; Pyšek, P.; Rabitsch, W.; Richardson, D.M.; Seebens, H.; van Kleunen, M.; van der Putten, W.H.; Vilà, M.; Bacher, S.For many species, human-induced environmental changes are important indirect drivers of range expansion into new regions. We argue that it is important to distinguish the range dynamics of such species from those that occur without, or with less clear, involvement of human-induced environmental changes. We elucidate the salient features of the rapid increase in the number of species whose range dynamics are human induced, and review the relationships and differences to both natural range expansion and biological invasions. We discuss the consequences for science, policy and management in an era of rapid global change and highlight four key challenges relating to basic gaps in knowledge, and the transfer of scientific understanding to biodiversity management and policy. We conclude that range-expanding species responding to human-induced environmental change will become an essential feature for biodiversity management and science in the Anthropocene. Finally, we propose the term neonative for these taxa.
- ItemDefining the impact of non-native species(Wiley Periodicals, Inc. on behalf of the Society for Conservation Biology, 2014) Jeschke, J.M.; Bacher, S.; Blackburn, T.M.; Dick, J.T.A.; Essl, F.; Evans, T.; Gaertner, M.; Hulme, P.E.; Kühn, I.; Mrugala, A.; Pergl, J.; Pyšek, P.; Rabitsch, W.; Ricciardi, A.; Richardson, D.M.; Sendek, A.; Vilá, M.; Winter, M.; Kumschick, S.Non-native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ecosystems and biodiversity. However, the impacts of most non-native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non-native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non-native species; help disentangle which aspects of scientific debates about non-native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio-economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts.
- ItemDrivers of future alien species impacts: an expert-based assessment(2020) Essl, F.; Lenzner, B.; Bacher, S.; Bailey, S.; Capinha, C.; Daehler, C.; Dullinger, S.; Genovesi, P.; Hui, C.; Hulme, P.E.; Jeschke, J.M.; Katsanevakis, S.; Kühn, I.; Leung, B.; Liebhold, A.; Liu, C.; MacIsaac, H.J.; Meyerson, L.A.; Nuñez, M.A.; Pauchard, A.; Pyšek, P.; Rabitsch, W.; Richardson, D.M.; Roy, H.E.; Ruiz, G.M.; Russell, J.C.; Sanders, N.J.; Sax, D.F.; Scalera, R.; Seebens, H.; Springborn, M.; Turbelin, A.; van Kleunen, M.; von Holle, B.; Winter, M.; Zenni, R.D.; Mattsson, B.J.; Roura-Pascual, N.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.
- ItemMAcroecological Framework for Invasive Aliens (MAFIA): disentangling large-scale context dependence in biological invasions(2020) Pyšek, P.; Bacher, S.; Kühn, I.; Novoa, A.; Catford, J.A.; Hulme, P.E.; Pergl, J.; Richardson, D.M.; Wilson, J.R.U.; Blackburn, T.M.Macroecology is the study of patterns, and the processes that determine those patterns, in the distribution and abundance of organisms at large scales, whether they be spatial (from hundreds of kilometres to global), temporal (from decades to centuries), and organismal (numbers of species or higher taxa). In the context of invasion ecology, macroecological studies include, for example, analyses of the richness, diversity, distribution, and abundance of alien species in regional floras and faunas, spatio-temporal dynamics of alien species across regions, and cross-taxonomic analyses of species traits among comparable native and alien species pools. However, macroecological studies aiming to explain and predict plant and animal naturalisations and invasions, and the resulting impacts, have, to date, rarely considered the joint effects of species traits, environment, and socioeconomic characteristics. To address this, we present the MAcroecological Framework for Invasive Aliens (MAFIA). The MAFIA explains the invasion phenomenon using three interacting classes of factors – alien species traits, location characteristics, and factors related to introduction events – and explicitly maps these interactions onto the invasion sequence from transport to naturalisation to invasion. The framework therefore helps both to identify how anthropogenic effects interact with species traits and environmental characteristics to determine observed patterns in alien distribution, abundance, and richness; and to clarify why neglecting anthropogenic effects can generate spurious conclusions. Event-related factors include propagule pressure, colonisation pressure, and residence time that are important for mediating the outcome of invasion processes. However, because of context dependence, they can bias analyses, for example those that seek to elucidate the role of alien species traits. In the same vein, failure to recognise and explicitly incorporate interactions among the main factors impedes our understanding of which macroecological invasion patterns are shaped by the environment, and of the importance of interactions between the species and their environment. The MAFIA is based largely on insights from studies of plants and birds, but we believe it can be applied to all taxa, and hope that it will stimulate comparative research on other groups and environments. By making the biases in macroecological analyses of biological invasions explicit, the MAFIA offers an opportunity to guide assessments of the context dependence of invasions at broad geographical scales.
- ItemOrigin of climatic data can determine the transferability of species distribution models(2020) Datta, A.; Schweiger, O.; Kühn, I.Methodological research on species distribution modelling (SDM) has so far largely focused on the choice of appropriate modelling algorithms and variable selection approaches, but the consequences of choosing amongst different sources of environmental data has scarcely been investigated. Bioclimatic variables are commonly used as predictors in SDMs. Currently, several online databases offer the same sets of bioclimatic variables, but they differ in underlying source of raw data and method of data processing (extrapolation and downscaling). In this paper, we asked whether predictive performance and spatial transferability of SDMs are affected by the choice of two different bioclimatic databases viz. WorldClim 2 and Chelsa 1.2. We used presence-absence data of the invasive plant Ageratina adenophora from the Western Himalaya for training SDMs and a set of independently-collected presence-only datasets from the Central and Eastern Himalaya to evaluate the transferability of the SDMs beyond the training range. We found that the performance of SDMs was, to a large degree, affected by the choice of the climatic dataset. Models calibrated on Chelsa 1.2 outperformed WorldClim 2 in terms of internal evaluation on the calibration dataset. However, when the model was transferred beyond the calibration range to the Central and Eastern Himalaya, models based on WorldClim 2 performed substantially better. We recommend that, in addition to the choice of predictor variables, the choice of predictor datasets with these variables should not be based merely on subjective decision whenever several options are available. Instead, such decisions should be based on robust evaluation of the most appropriate dataset for a given geographic region and species being modelled. Moreover, decisions could also depend on the objective of the study, i.e. projecting within the calibration range or beyond. Therefore, a quantitative evaluation of predictor datasets from alternative sources should be routinely performed as an integral part of the modelling procedure.
- 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.