Browsing by Author "Roy, Helen E."
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- ItemHorizon scanning for invasive alien species with the potential to threaten biodiversity in Great Britain(John Wiley & Sons, 2014) Roy, Helen E.; Peyton, Jodey; Aldridge, David C.; Bantock, Tristan; Blackburn, Tim M.; Britton, Robert; Clark, Paul; Cook, Elizabeth; Dehnen-Schmutz, Katharina; Dines, Trevor; Dobson, Michael; Edwards, Francois; Harrower, Colin; Harvey, Martin C.; Minchin, Dan; Noble, David G.; Parrott, Dave; Pocock, Michael J. O.; Preston, Chris D.; Roy, Sugoto; Salisbury, Andrew; Schonrogge, Karsten; Sewell, Jack; Shaw, Richard H.; Stebbing, Paul; Stewart, Alan J. A.; Walker, Kevin J.Invasive alien species (IAS) are considered one of the greatest threats to biodiversity, particularly through their interactions with other drivers of change. Horizon scanning, the systematic examination of future potential threats and opportunities, leading to prioritization of IAS threats is seen as an essential component of IAS management. Our aim was to consider IAS that were likely to impact on native biodiversity but were not yet established in the wild in Great Britain. To achieve this, we developed an approach which coupled consensus methods (which have previously been used for collaboratively identifying priorities in other contexts) with rapid risk assessment. The process involved two distinct phases: 1. Preliminary consultation with experts within five groups (plants, terrestrial invertebrates, freshwater invertebrates, vertebrates and marine species) to derive ranked lists of potential IAS. 2. Consensus-building across expert groups to compile and rank the entire list of potential IAS. Five hundred and ninety-one species not native to Great Britain were considered. Ninety-three of these species were agreed to constitute at least a medium risk (based on score and consensus) with respect to them arriving, establishing and posing a threat to native biodiversity. The quagga mussel, Dreissena rostriformis bugensis, received maximum scores for risk of arrival, establishment and impact; following discussions the unanimous consensus was to rank it in the top position. A further 29 species were considered to constitute a high risk and were grouped according to their ranked risk. The remaining 63 species were considered as medium risk, and included in an unranked long list. The information collated through this novel extension of the consensus method for horizon scanning provides evidence for underpinning and prioritizing management both for the species and, perhaps more importantly, their pathways of arrival. Although our study focused on Great Britain, we suggest that the methods adopted are applicable globally.
- ItemScientists’ 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.
- ItemSocio-economic impact classification of alien taxa (SEICAT)(British Ecological Society, 2018) Bacher, Sven; Blackburn, Tim M.; Essl, Franz; Genovesi, Piero; Heikkila, Jaakko; Jeschke, Jonathan M.; Jones, Glyn; Keller, Reuben; Kenis, Marc; Kueffer, Christoph; Martinou, Angeliki F.; Nentwig, Wolfgang; Pergl, Jan; Pysek, Petr; Rabitsch, Wolfgang; Richardson, David M.; Roy, Helen E.; Saul, Wolf-Christian; Scalera, Riccardo; Vila, Montserrat; Wilson, John R. U.; Kumschick, Sabrina1. 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.
- ItemTrait positions for elevated invasiveness in adaptive ecological networks(Springer, 2021) Hui, Cang; Richardson, David M.; Landi, Pietro; Minoarivelo, Henintsoa O.; Roy, Helen E.; Latombe, Guillaume; Jing, Xin; CaraDonna, Paul J.; Gravel, Dominique; Beckage, Brian; Molofsky, JaneOur ability to predict the outcome of invasion declines rapidly as non-native species progress through intertwined ecological barriers to establish and spread in recipient ecosystems. This is largely due to the lack of systemic knowledge on key processes at play as species establish self-sustaining populations within the invaded range. To address this knowledge gap, we present a mathematical model that captures the eco-evolutionary dynamics of native and non-native species interacting within an ecological network. The model is derived from continuous-trait evolutionary game theory (i.e., Adaptive Dynamics) and its associated concept of invasion fitness which depicts dynamic demographic performance that is both trait mediated and density dependent. Our approach allows us to explore how multiple resident and non-native species coevolve to reshape invasion performance, or more precisely invasiveness, over trait space. The model clarifies the role of specific traits in enabling non-native species to occupy realised opportunistic niches. It also elucidates the direction and speed of both ecological and evolutionary dynamics of residing species (natives or non-natives) in the recipient network under different levels of propagule pressure. The versatility of the model is demonstrated using four examples that correspond to the invasion of (i) a horizontal competitive community; (ii) a bipartite mutualistic network; (iii) a bipartite antagonistic network; and (iv) a multi-trophic food web. We identified a cohesive trait strategy that enables the success and establishment of non-native species to possess high invasiveness. Specifically, we find that a non-native species can achieve high levels of invasiveness by possessing traits that overlap with those of its facilitators (and mutualists), which enhances the benefits accrued from positive interactions, and by possessing traits outside the range of those of antagonists, which mitigates the costs accrued from negative interactions. This ‘central-to-reap, edge-to-elude’ trait strategy therefore describes the strategic trait positions of non-native species to invade an ecological network. This model provides a theoretical platform for exploring invasion strategies in complex adaptive ecological networks.
- ItemTroubling travellers : are ecologically harmful alien species associated with particular introduction pathways?(Pensoft Publishers, 2017) Pergl, Jan; Pysek, Petr; Bacher, Sven; Essl, Franz; Genovesi, Piero; Harrower, Colin A.; Hulme, Philip E.; Jeschke, Jonathan M.; Kenis, Marc; Kuhn, Ingolf; Perglova, Irena; Rabitsch, Wolfgang; Roques, Alain; Roy, David B.; Roy, Helen E.; Vila, Montserrat; Winter, Marten; Nentwig, WolfgangPrioritization of introduction pathways is seen as an important component of the management of biological invasions. We address whether established alien plants, mammals, freshwater fish and terrestrial invertebrates with known ecological impacts are associated with particular introduction pathways (release, escape, contaminant, stowaway, corridor and unaided). We used the information from the European alien species database DAISIE (www.europe-aliens.org) supplemented by the EASIN catalogue (European Alien Species Information Network), and expert knowledge. Plants introduced by the pathways release, corridor and unaided were disproportionately more likely to have ecological impacts than those introduced as contaminants. In contrast, impacts were not associated with particular introduction pathways for invertebrates, mammals or fish. Thus, while for plants management strategies should be targeted towards the appropriate pathways, for animals, management should focus on reducing the total number of taxa introduced, targeting those pathways responsible for high numbers of introductions. However, regardless of taxonomic group, having multiple introduction pathways increases the likelihood of the species having an ecological impact. This may simply reflect that species introduced by multiple pathways have high propagule pressure and so have a high probability of establishment. Clearly, patterns of invasion are determined by many interacting factors and management strategies should reflect this complexity.
- ItemA vision for global monitoring of biological invasions(Elsevier Ltd., 2017) Latombe, Guillaume; Pysek, Petr; Jeschke, Jonathan M.; Blackburn, Tim M.; Bacher, Sven; Capinha, Cesar; Costello, Mark J.; Fernandez, Miguel; Gregory, Richard D.; Hobern, Donald; Hui, Cang; Jetz, Walter; Kumschick, Sabrina; McGrannachan, Chris; Pergl, Jan; Roy, Helen E.; Scalera, Riccardo; Squires, Zoe E.; Wilson, John R. U.; Winter, Marten; Genovesi, Piero; McGeoch, Melodie A.Managing biological invasions relies on good global coverage of species distributions. Accurate information on alien species distributions, obtained from international policy and cross-border co-operation, is required to evaluate trans-boundary and trading partnership risks. However, a standardized approach for systematically monitoring alien species and tracking biological invasions is still lacking. This Perspective presents a vision for global observation and monitoring of biological invasions. We show how the architecture for tracking biological invasions is provided by a minimum information set of Essential Variables, global collaboration on data sharing and infrastructure, and strategic contributions by countries. We show how this novel, synthetic approach to an observation system for alien species provides a tangible and attainable solution to delivering the information needed to slow the rate of new incursions and reduce the impacts of invaders. We identify three Essential Variables for Invasion Monitoring; alien species occurrence, species alien status and alien species impact. We outline how delivery of thisminimum information set by joint, complementary contributions from countries and global community initiatives is possible. Country contributions are made feasible using a modular approach where all countries are able to participate and strategically build their contributions to a global information set over time. The vision we outline will deliver wide-ranging benefits to countries and international efforts to slow the rate of biological invasions and minimize their environmental impacts. These benefits will accrue over time as global coverage and information on alien species increases.