Browsing by Author "Kueffer, C."
Now showing 1 - 8 of 8
Results Per Page
Sort Options
- ItemAlien plants as mediators of ecosystem services and disservices in urban systems: a global view(Springer, 2017) Potgieter, L.J.; Gaertner, M.; Kueffer, C.; Larson, B.M.H.; Livingstone, S.W.; O'Farrell, P.J.; Richardson, D.M.Urban areas have unique assemblages of species which are governed by novel ecological processes. People living in these environments have specific needs and demands in terms of ecosystem services (ES). Urban ecosystems are transformed in many ways by human activities and their floras comprise a high proportion of alien plant species, many of which were intentionally introduced to provide, augment or restore ES. Urban environments also have novel disturbance regimes and provide colonization sites for the establishment, dispersal and proliferation of alien plant species; such conditions often generate biological invasions which may cause marked changes to ES. We review the roles that alien plants play in providing urban ES and ecosystem disservices (EDS) globally. We identify the main ES and EDS associated with alien plants, and highlight the key species involved. A literature search revealed 335 papers, representing studies in 58 cities or urban areas in 27 countries. These studies recorded 337 alien plant species, contributing to 39 different ES and 27 EDS–310 species were recorded as contributing to ES and 53 species to EDS. A small number of alien plant taxa were frequently recorded as providing multiple ES in many urban ecosystems; the 10 most recorded species accounted for 21% of the ES recorded. Some of these species also result in significant EDS; three species accounted for 30% of the EDS recorded. Cultural services (notably aesthetics) are the most reported ES provided by alien plants in urban areas of developed countries, while provisioning services (notably food production) are most reported in developing countries. The most commonly studied EDS provided by alien plants is the impact on human health (notably allergic reactions). Eighty percent of studies on alien plants and ES and EDS have been done in developed countries. To elucidate the full range of effects of alien plants, more work is needed in developing countries. Urban planners and managers need to be mindful of both the positive and negative impacts of alien plant species to maximise the provision of ES.
- ItemDifferent environmental drivers of alien tree invasion affect different life-stages and operate at different spatial scales(Elsevier B.V., 2019) Vicente, J.R.; Kueffer, C.; Richardson, D.M.; Vaz, A.S.; Cabral, J.A.; Hui, C.; Araujo, M.B.; Kuhn, I.; Kull, C.A.; Verburg, P.H.; Marchante, E.; Honrado, J.P.Identifying the key factors driving invasion processes is crucial for designing and implementing appropriate management strategies. In fact, the importance of (model-based) prevention and early detection was highlighted in the recent European Union regulation on Invasive Alien Species. Models based on abundance estimates for different age/size classes would represent a significant improvement relative to the more usual models based only on species’ occurrence data. Here, we evaluate the relative contribution of different environmental drivers to the spatial patterns of abundance of several height classes (or life-stages) of invasive tree populations at the regional scale, using a data-driven hierarchical modelling approach. A framework for modelling life-stages to obtain spatial projections of their potential occurrence or abundance has not been formalized before. We used Acacia dealbata (Silver-wattle) as a test species in northwest of Portugal, a heavily invaded region, and applied a multimodel inference to test the importance of various environmental drivers in explaining the abundance patterns of five plant height classes in local landscape mosaics. The ensemble of height classes is considered here as a proxy for population dynamics, life-stages and age of adult trees. In this test with A. dealbata, we used detailed field data on population height structure and calibrated an independent model for each height class. We found evidence to support our hypothesis that the distribution of height classes is mostly influenced by distinct factors operating at different scales. The spatial projections which resulted from several height class models provide an overview of population structure and invasion dynamics considering various life-stages, that is widely used in biodiversity and invasion research. The approach proposed here provides a framework to guide forest management to deal more effectively with plant invasions. It allows to test the effects of key invasion factors (depending on the focal species and on data availability) and supports the spatial identification of suitable areas for invasive species’ occurrence while also accounting for the structural complexity of invasive species populations, thereby anticipating future invasion dynamics. The approach thus constitutes a step forward for establishing management actions at appropriate spatial scales and for focusing on earlier stages of invasion and their respective driving factors (regeneration niche), thereby enhancing the efficiency of control actions on major forest invaders.
- ItemIntegrative invasion science: model systems, multi-site studies, focused meta-analysis and invasion syndromes(Wiley-Blackwell, 2013) Kueffer, C.; Pysek, P.; Richardson, D.M.Invasion science is a very active subdiscipline of ecology. However, some scientists contend that theoretical integration has been limited and that predictive power remains weak. This paper, focusing on plants, proposes a new multi-pronged research strategy that builds on recent advances in invasion science. More intensive studies on particular model organisms and ecosystems are needed to improve our understanding of the full suite of interacting factors that influence invasions (‘model system research’). At the same time, comparative studies across many study systems are essential for unravelling the context-dependencies of insights that emerge from particular studies (‘multi-site studies’); and quantitative synthesis based on large datasets should be constrained to well-defined theoretical domains (‘focused meta-analysis’). We also suggest ways for better integration of information about species biology and ecosystem characteristics (‘invasion syndromes’). We expect that a resulting theory of invasions will need to be conceived as a somewhat heterogeneous conglomerate of elements of varying generality and predictive power: laws that apply to well-specified domains, general concepts and theoretical frameworks that can guide thinking in research and management, and in-depth knowledge about the drivers of particular invasions.
- ItemInvasion syndromes: a systematic approach for predicting biological invasions and facilitating effective management(2020) Novoa, A.; Richardson, D.M.; Pyšek, P.; Meyerson, L.A.; Bacher, S.; Canavan, S.; Catford, J.A.; Čuda, J.; Essl, F.; Foxcroft, L.C.; Genovesi, P.; Hirsch, H.; Hui, C.; Jackson, M.C.; Kueffer, C.; Le Roux, J.J.; Measey, J.; Mohanty, N.P.; Moodley, D.; Müller-Schärer, H.; Packer, J.G.; Pergl, J.; Robinson, T.B.; Saul, W.C.; Shackleton, R.T.; Visser, V.; Weyl, O.L.F.; Yannelli, F.A.; Wilson, J.R.U.Our ability to predict invasions has been hindered by the seemingly idiosyncratic context-dependency of individual invasions. However, we argue that robust and useful generalisations in invasion science can be made by considering “invasion syndromes” which we define as “a combination of pathways, alien species traits, and characteristics of the recipient ecosystem which collectively result in predictable dynamics and impacts, and that can be managed effectively using specific policy and management actions”. We describe this approach and outline examples that highlight its utility, including: cacti with clonal fragmentation in arid ecosystems; small aquatic organisms introduced through ballast water in harbours; large ranid frogs with frequent secondary transfers; piscivorous freshwater fishes in connected aquatic ecosystems; plant invasions in high-elevation areas; tall-statured grasses; and tree-feeding insects in forests with suitable hosts. We propose a systematic method for identifying and delimiting invasion syndromes. We argue that invasion syndromes can account for the context-dependency of biological invasions while incorporating insights from comparative studies. Adopting this approach will help to structure thinking, identify transferrable risk assessment and management lessons, and highlight similarities among events that were previously considered disparate invasion phenomena.
- ItemThe progress of interdisciplinarity in invasion science(Royal Swedish Academy of Sciences, 2017) Vaz, A.S.; Kueffer, C.; Kull, C.A.; Richardson, D.M.; Schindler, S.; Munoz-Pajares, A.J.; Vicente, J.R.; Martins, J.; Hui, C.; Kuhn, I.; Honrado, J.P.Interdisciplinarity is needed to gain knowledge of the ecology of invasive species and invaded ecosystems, and of the human dimensions of biological invasions. We combine a quantitative literature review with a qualitative historical narrative to document the progress of interdisciplinarity in invasion science since 1950. Our review shows that 92.4% of interdisciplinary publications (out of 9192) focus on ecological questions, 4.4% on social ones, and 3.2% on social–ecological ones. The emergence of invasion science out of ecology might explain why interdisciplinarity has remained mostly within the natural sciences. Nevertheless, invasion science is attracting social–ecological collaborations to understand ecological challenges, and to develop novel approaches to address new ideas, concepts, and invasion-related questions between scholars and stakeholders. We discuss ways to reframe invasion science as a field centred on interlinked social– ecological dynamics to bring science, governance and society together in a common effort to deal with invasions.
- ItemScientific and normative foundations for the valuation of alien-species impacts: Thirteen core principles(Oxford University Press, 2017) Essl, F.; Hulme, P.E.; Jeschke, J.M.; Keller, R.; Pysek, P.; Richardson, D.M.; Saul, W.C.; Bacher, S.; Dullinger, S.; Estevez, R.A.; Kueffer, C.; Roy, H.E.; Seebens, H.; Rabitsch, W.Biological invasions cause many impacts that differ widely in how they are perceived. We argue that many conflicts in the valuation of the impacts of alien species are attributable to differences in the framing of the issue and implicit assumptions—such conflicts are often not acknowledged. We present 13 principles that can help guide valuation and therefore inform the management of alien species. Seven of these relate to the science domain, representing aspects of change caused by alien species that can be measured or otherwise assessed using scientific methods. The remaining six principles invoke values, risk perception, and environmental ethics, but also cognitive and motivational decision biases. We illustrate the consequences of insufficient appreciation of these principles. Finally, we provide guidance rooted in political agreements and environmental ethics for improving the consideration of the consequences of these principles and present appropriate tools for management decisions relating to alien species.
- ItemSocio-economic impact classification of alien taxa (SEICAT)(British Ecological Society, 2018) Bacher, S.; Blackburn, T.M.; Essl, F.; Genovesi, P.; Heikkilä, J.; Jeschke, J.M.; Jones, G.; Keller, R.; Kenis, M.; Kueffer, C.; Martinou, A.F.; Nentwig, W.; Pergl, J.; Pyšek, P.; Rabitsch, W.; Richardson, D.M.; Roy, H.E.; Saul, W.-C.; Scalera, R.; Vilà, M.; Wilson, J.R.U.; Kumschick, S.1. Many alien taxa are known to cause socio-economic impacts by affecting the different constituents of human well-being (security; material and non-material assets; health; social, spiritual and cultural relations; freedom of choice and action). Attempts to quantify socio-economic impacts in monetary terms are unlikely to provide a useful basis for evaluating and comparing impacts of alien taxa because they are notoriously difficult to measure and important aspects of human well-being are ignored. 2. Here, we propose a novel standardised method for classifying alien taxa in terms of the magnitude of their impacts on human well-being, based on the capability approach from welfare economics. The core characteristic of this approach is that it uses changes in peoples’ activities as a common metric for evaluating impacts on well-being. 3. Impacts are assigned to one of five levels, from Minimal Concern to Massive, according to semi-quantitative scenarios that describe the severity of the impacts. Taxa are then classified according to the highest level of deleterious impact that they have been recorded to cause on any constituent of human well-being. The scheme also includes categories for taxa that are not evaluated, have no alien population, or are data deficient, and a method for assigning uncertainty to all the classifications. To demonstrate the utility of the system, we classified impacts of amphibians globally. These showed a variety of impacts on human well-being, with the cane toad (Rhinella marina) scoring Major impacts. For most species, however, no studies reporting impacts on human well-being were found, i.e. these species were data deficient. 4. The classification provides a consistent procedure for translating the broad range of measures and types of impact into ranked levels of socio-economic impact, assigns alien taxa on the basis of the best available evidence of their documented deleterious impacts, and is applicable across taxa and at a range of spatial scales. The system was designed to align closely with the Environmental Impact Classification for Alien Taxa (EICAT) and the Red List, both of which have been adopted by the International Union of Nature Conservation (IUCN), and could therefore be readily integrated into international practices and policies.
- ItemUsing the “regime shift” concept in addressing social-ecological change(John Wiley & Sons, Inc, 2018) Kull, C.A.; Kueffer, C.; Richardson, D.M.; Vaz, A.S.; Vicente, J.R.; Honrado, J.P.‘Regime shift’ has emerged as a key concept in the environmental sciences. The concept has roots in complexity science and its ecological applications, and is increasingly applied to intertwined social and ecological phenomena. Yet what exactly is a regime shift? We explore this question at three nested levels. First, we propose a broad, contingent, multi-perspective epistemological basis for the concept, seeking to build bridges between its complexity theory origins and critiques from science studies, political ecology, and environmental history. Second, we define the concept in a way that is consistent with this epistemology, building on previous work on speed, scale, stickiness, and interrelationships, but also emphasising human perceptions and rhetorical uses of the notion. Third, we propose a novel typology of the ways in which the regime shift concept is used in analysing social–environmental phenomena in geography and beyond. These uses are categorised along two axes. On the one side, we distinguish between description of past or present changes and normative prescriptions for the future. On the other side, we distinguish between whether the focus is onmaterial shifts (social and ecological) or conceptual shifts (discourses and ideas).We illustrate the typology with reference to social–environmental changes in landscapes around the world that are dominated by plantations or the widespread naturalisation of Australian Acacia species. We conclude that the regime shift concept is a boundary object with value as both an analytical and communicative tool in addressing social–environmental challenges.