When are eradication campaigns successful? A test of common assumptions

Eradication aims at eliminating populations of alien organisms from an area. Since not all eradications are successful, several factors have been proposed in the literature (mainly by referring to case studies) to be crucial for eradication success, such as infestation size or reaction time. To our knowledge, however, no study has statistically evaluated which factors affect eradication success and attempted to determine their relative importance. We established a unique global dataset on 136 eradication campaigns against 75 species (invasive alien invertebrates, plants and plant pathogens) and statistically tested whether the following factors, proposed by others were significantly related to eradication success: (1) the reaction time between the arrival/detection of the organism and the start of the eradication campaign; (2) the spatial extent of the infestation; (3) the level of biological knowledge of the organism; and (4) insularity. Of these, only the spatial extent of the infestation was significantly related to the eradication outcome: local campaigns were more successful than regional or national campaigns. Reaction time, the level of knowledge and insularity were all unrelated to eradication success. Hence, some factors suggested as being crucial may be less important than previously thought, at least for the organisms tested here. We found no differences in success rates among taxonomic groups or geographic regions. We recommend that eradication measures should generally concentrate on the very early phase of invasions when infestations are still relatively smal

are ecologically harmful alien species associated with particular introduction pathways?

Prioritization 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

Framework and guidelines for implementing the proposed IUCN Environmental Impact Classification for Alien Taxa (EICAT)

Recently, Blackburn et al. (2014) developed a simple, objective and transparent method for classifying alien taxa in terms of the magnitude of their detrimental environmental impacts in recipient areas. Here, we present a comprehensive framework and guidelines for implementing this method, which we term the Environmental Impact Classification for Alien Taxa, or EICAT. We detail criteria for applying the EICAT scheme in a consistent and comparable fashion, prescribe the supporting information that should be supplied along with classifications, and describe the process for implementing the method. This comment aims to draw the attention of interested parties to the framework and guidelines, and to present them in their entirety in a location where they are freely accessible to any potential users

Comparing impacts of alien plants and animals in Europe using a standard scoring system

© 2015 British Ecological Society. Alien species can change the recipient environment in various ways, and some of them cause considerable damage. Understanding such impacts is crucial to direct management actions. This study addresses the following questions: Is it possible to quantify impact across higher taxa in a comparative manner? Do impacts differ between taxonomic groups? How are environmental and socio-economic impacts related? Can impacts be predicted based on those in other regions? To address these questions, we reviewed literature describing the impacts of 300 species from five major taxonomic groups: mammals, birds, fish, terrestrial arthropods and plants. To make very diverse impact measures comparable, we used the semi-quantitative generic impact scoring system (GISS) which describes environmental and socio-economic impacts using twelve categories. In each category, scores range from zero (no impact known or detectable) to five (the highest possible impact). Using the same scoring system for taxa as diverse as invertebrates, vertebrates and plants, we found that overall, alien mammals in Europe have the highest impact, while fish have the lowest. Terrestrial arthropods were found to have the lowest environmental impact, while fish had relatively low socio-economic impact. Overall, the magnitude of environmental and socio-economic impacts of individual alien species is highly correlated. However, at the species level, major deviations are found. For mammals and birds, the impacts in invaded ranges outside of Europe are broadly similar to those recorded for alien species within Europe, indicating that a consideration of the known impacts of a species in other regions can be generally useful when predicting the impacts of an alien species. However, it should be noted that this pattern is not consistent across all mammal and bird orders, and thus, such information should be considered with caution. Synthesis and applications. Comparing the impacts of alien species across taxa is necessary for prioritizing management efforts and effective allocation of resources. By applying the generic impact scoring system (GISS) to five major taxonomic groups, we provide the basis for a semi-quantitative cross-taxa listing process (e.g. 'black lists' or 100-worst-lists). If more data are collated from different geographical regions and habitats using standard GISS protocols, risk assessments for alien species based on rigorous measures of impact could be improved by taking into account local variation, and context dependence of impacts. This would also allow studies at lower taxonomic levels, and within-taxon analyses of functional groups and guilds. Comparing the impacts of alien species across taxa is necessary for prioritizing management efforts and effective allocation of resources. By applying the generic impact scoring system (GISS) to five major taxonomic groups, we provide the basis for a semi-quantitative cross-taxa listing process (e.g. 'black lists' or 100-worst-lists). If more data are collated from different geographical regions and habitats using standard GISS protocols, risk assessments for alien species based on rigorous measures of impact could be improved by taking into account local variation, and context dependence of impacts. This would also allow studies at lower taxonomic levels, and within-taxon analyses of functional groups and guilds.Peer Reviewe

Population ecology of the invasive alien plant Heracleum mantegazzianu

Katedra botanikyDepartment of BotanyPřírodovědecká fakultaFaculty of Scienc

Comparing impacts of alien plants and animals in Europe using a standard scoring system

Alien species can change the recipient environment in various ways, and some of them cause considerable damage. Understanding such impacts is crucial to direct management actions. This study addresses the following questions: Is it possible to quantify impact across higher taxa in a comparative manner? Do impacts differ between taxonomic groups? How are environmental and socio-economic impacts related? Can impacts be predicted based on those in other regions?To address these questions, we reviewed literature describing the impacts of 300 species from five major taxonomic groups: mammals, birds, fish, terrestrial arthropods and plants. To make very diverse impact measures comparable, we used the semi-quantitative generic impact scoring system (GISS) which describes environmental and socio-economic impacts using twelve categories. In each category, scores range from zero (no impact known or detectable) to five (the highest possible impact).Using the same scoring system for taxa as diverse as invertebrates, vertebrates and plants, we found that overall, alien mammals in Europe have the highest impact, while fish have the lowest. Terrestrial arthropods were found to have the lowest environmental impact, while fish had relatively low socio-economic impact.Overall, the magnitude of environmental and socio-economic impacts of individual alien species is highly correlated. However, at the species level, major deviations are found.For mammals and birds, the impacts in invaded ranges outside of Europe are broadly similar to those recorded for alien species within Europe, indicating that a consideration of the known impacts of a species in other regions can be generally useful when predicting the impacts of an alien species. However, it should be noted that this pattern is not consistent across all mammal and bird orders, and thus, such information should be considered with caution.Synthesis and applications. Comparing the impacts of alien species across taxa is necessary for prioritizing management efforts and effective allocation of resources. By applying the generic impact scoring system (GISS) to five major taxonomic groups, we provide the basis for a semi-quantitative cross-taxa listing process (e.g. ‘black lists’ or 100-worst-lists). If more data are collated from different geographical regions and habitats using standard GISS protocols, risk assessments for alien species based on rigorous measures of impact could be improved by taking into account local variation, and context dependence of impacts. This would also allow studies at lower taxonomic levels, and within-taxon analyses of functional groups and guilds

Framework and guidelines for implementing the proposed IUCN Environmental Impact Classification for Alien Taxa (EICAT)

Recently, Blackburn et al. (2014) developed a simple, objective and transparent method for classifying alien taxa in terms of the magnitude of their detrimental environmental impacts in recipient areas. Here, we present a comprehensive framework and guidelines for implementing this method, which we term the Environmental Impact Classification for Alien Taxa, or EICAT. We detail criteria for applying the EICAT scheme in a consistent and comparable fashion, prescribe the supporting information that should be supplied along with classifications, and describe the process for implementing the method. This comment aims to draw the attention of interested parties to the framework and guidelines, and to present them in their entirety in a location where they are freely accessible to any potential users.Peer Reviewe

Ecological Impacts of Alien Species: Quantification, Scope, Caveats, and Recommendations

Despite intensive research during the past decade on the effects of alien species, invasion science still lacks the capacity to accurately predict the impacts of those species and, therefore, to provide timely advice to managers on where limited resources should be allocated. This capacity has been limited partly by the context-dependent nature of ecological impacts, research highly skewed toward certain taxa and habitat types, and the lack of standardized methods for detecting and quantifying impacts. We review different strategies, including specific experimental and observational approaches, for detecting and quantifying the ecological impacts of alien species. These include a four-way experimental plot design for comparing impact studies of different organisms. Furthermore, we identify hypothesis-driven parameters that should be measured at invaded sites to maximize insights into the nature of the impact. We also present strategies for recognizing high-impact species. Our recommendations provide a foundation for developing systematic quantitative measurements to allow comparisons of impacts across alien species, sites, and tim

Defining the Impact of Non-Native Species

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

ARES(2014)2425342 - 22/07/2014. Organisation and running of a scientific workshop to complete selected invasive alien species (IAS) risk assessments

The introduction and spread of invasive alien species (IAS) constitutes one of the most important drivers of global change in biodiversity and ecosystem services. Robust risk assessment methods are required for IAS to provide the foundation upon which to prioritise appropriate action. In a previous study (Roy, Schonrogge et al. 2014) minimum standards were developed to provide an assessment framework for risk assessments and ultimately for underpinning the development of a proposed list of “IAS of EU concern”, in accordance to the provisions of the Regulation (EU) No 1143/2014 of the European Parliament and of the Council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species. In practice, of the protocols assessed in detail, only four (GB NNRA, EPPO DSS, Harmonia+ and ENSARS) were sufficiently compliant with the minimum standards to be considered and of these only the GB NNRA and EPPO DSS have published IAS risk assessments. As a result, using the information from such “substantially compliant” protocols, a draft list of approximately 50 species was compiled. It is important to note that this list of species is based on availability of robust risk assessments already completed through methods which are almost compliant with the minimum standards, and it does not constitute the list of “IAS of EU concern”. In view of the application of the forthcoming EU Regulation on IAS (and building-on ENV.B.2/ETU/2013/0026) the Commission hosted a 2-day scientific workshop to examine the selected risk assessments and pool the existing knowledge existing in the EU to complete the missing information, on the basis of robust scientific evidence, in order to make them fully compliant with the minimum standards, wherever possible. The workshop was led by Helen Roy (CEH) and Riccardo Scalera (ISSG). An additional 16 experts from fifteen member states were selected based on their expertise in invasion biology and represented a breadth of expertise from a variety of perspectives including taxonomic (all taxa), environmental (freshwater, marine and terrestrial), impacts (environmental, socio-economic and health) and disciplines (ecologists, conservation practitioners, scientists, policy-makers, risk assessors). In view of the gaps across risk assessments for ecosystem services and climate change two experts were invited to guide the development of approaches for these specific themes. In total the risk assessments for 56 species were considered. The GB NNRA and EPPO DSS have published IAS risk assessments which, when considering species that score medium to high impact, together cover 51 species (noting that Fallopia japonica and F. sachalinensis are separate species). Two further risk assessments were suggested for consideration by the GB Non-Native Species Secretariat which follow the GB NNRA protocol: coati (Nasua nasua) and skunk (Mephitis mephitis), although scored as low impact. Finally an additional three species have been considered through new European–wide risk assessments, with the reported outcome of high impact, for this project which again follow the GB NNRA protocol: Pallas squirrel (Callosciurus erythraeus), grey squirrel (Sciurus carolinensis) and coypu (Myocastor coypus). The main gaps across all risk assessments were in relation to climate change and ecosystem services but additional information was also required on benefits as mentioned with minimum standard “Description (Taxonomy, invasion history, distribution range (native and introduced), geographic scope, socio-economic benefits)” and in some cases information to support the minimum standard “Includes status (threatened or protected) of species or habitat under threat“ was missing. It was agreed that systematic consideration of a list of questions in relation to the minimum standards on ecosystem services and climate change would be useful guidance for experts. An outline of the approaches agreed through the workshop for the minimum standards “Includes possible effects of climate change in the foreseeable future“ and “Can broadly assess environmental impact with respect to ecosystem services” were developed as guidance for documenting information in relation to climate change and ecosystem services. Each species was considered separately with the experts providing an overview of the information available for addressing the identified gaps. After all species had been considered the workshop participants (excluding the EC, Helen Roy and Riccardo Scalera) adopted a consensus approach to confirm whether or not the risk assessment was compliant with the minimum standards and whether the overall score of the risk assessment remained applicable. No changes were made to the scores but any recommendations were noted. There were very few recommendations for change. The outcome for each risk assessment was agreed and summarised as “compliant” or “not compliant” with the minimum standards. Of the risk assessments for the 56 species considered through this project, 53 were agreed to be fully compliant with the minimum standards. However, Pacific oyster, Crassostrea gigas, although compliant with the minimum standards should be excluded as it is not within the scope of the regulation (see art 2.e) because it is listed in annex IV of Council Regulation (EC) No 708/2007 of 11 June 2007 concerning use of alien and locally absent species in aquaculture. Four of the risk assessments were not considered to be compliant because of major information gaps: Elodea canadensis (Canadian pondweed), Heracleum mantegazzianum (giant hogweed), M. mephitis (skunk), N. nasua (coati)