Search

One of the most problematic invasive species in Europe are knotweeds from genus Reynoutria (Fallopia) which have significant negative impact on the native communities as well on human activities. Therefore, they are a target of many control programmes. Due to their high regeneration potential, their management is problematic, and only chemical treatment is reported to be sufficiently effective. The aim of this paper was to describe and analyse the patterns of Reynoutria invasion under long-term chemical treatment with glyphosate-based herbicide in The Morávka river floodplain, Czech Republic. The data covers 17 years of management which started with the European project “Preservation of alluvial forest habitats in the Morávka river basin”. We focus on (i) assessment of Reynoutria distribution during long-term management, (ii) analysis of the change of distribution according to the habitat, and (iii) discussion of the optimal management strategy based on the long-term data. Distribution data was obtained using GNSS field mapping. Before the start of the study in 2007, Reynoutria stands covered 29% of the study area (96.9 ha). As a result of systematic whole area chemical management, the extent decreased to 19.6% (65.3 ha) in 2009, and even reached 14.5% (48.2 ha) in 2013, three years after its end. Due to implementation of local chemical management in the following years, the area of Reynoutria was maintained at similar level, with minimum value 41.8 ha in 2018 and a slight increase in recent mapping in 2023. Beside the extent, the structure and coverage of invaded sites was analysed. There was a clear trend of fragmentation of larger polycormons with high coverage into many smaller and less dense ones as a result of chemical spraying. The average size of Reynoutria stand decreased from 0.61 ha in 2007 to half in 2013 (0.32 ha) to 0.15 ha in 2023. Testing of the effects of time, habitat, and biotope did not reveal significant differences of changes of extent and abundance over different environments (forest, open, bare ground), which indicates that there are no differences in reaction to management in the studied habitat and vegetation types. Our study provides a robust and unique overview of the invasion, reinvasion, and suppression dynamics for an important invasive species. If herbicide management is used, chemical treatment must be quite long-term as even three years of intensive glyphosate foliar spray application was not sufficient for the complete eradication of Reynoutria. Therefore, we propose the following procedure for effective chemical management of Reynoutria: 1) In largely infested sites, the first step is to reduce the distribution of Reynoutria stands to isolated polycormons. This phase can last 3–5 years. 2) After reaching the state of sparse distribution of Reynoutria, we recommend herbicide application only in periods of every 3–5 years depending on the local context and rate of regrowth. 3) At sites exposed to soil disturbances, where the soil is contaminated by fragments of Reynoutria rhizomes, there is a need to apply herbicide immediately to target newly resprouting individuals.

Abstract A large number of non‐native trees (NNTs) have been introduced globally and widely planted, contributing significantly to the world's economy. Although some of these species present a limited risk of spreading beyond their planting sites, a growing number of NNTs are spreading and becoming invasive leading to diverse negative impacts on biodiversity, ecosystem functions and human well‐being. To help minimize the negative impacts and maximize the economic benefits of NNTs, Brundu et al. developed eight guidelines for the sustainable use of NNTs globally—the Global Guidelines for the Use of NNTs (GG‐NNTs). Here, we used an online survey to assess perceptions of key stakeholders towards NNTs, and explore their knowledge of and compliance with the GG‐NNTs. Our results show that stakeholders are generally aware that NNTs can provide benefits and cause negative impacts, often simultaneously and they consider that their organization complies with existing regulations and voluntary agreements concerning NNTs. However, they are not aware of or do not apply most of the eight recommendations included in the GG‐NNTs. We conclude that effectively managing invasions linked to NNTs requires both more communication efforts using an array of channels for improving stakeholder awareness and implementation of simple measures to reduce NNT impacts (e.g. via GG‐NNTs), and a deeper understanding of the barriers and reluctance of stakeholders to manage NNT invasions. Read the free Plain Language Summary for this article on the Journal blog.

Plant invasion science has made a substantial progress in documenting the impacts of aliens, but comparisons with the impacts of native dominants are still rare. Further, the impacts on larger spatial scales remain poorly understood. We recorded the impacts of 10 native and nine invasive dominant plants in the Czech Republic on species richness and Shannon diversity by comparing communities with high vs. low cover of the dominant species. To estimate the impacts at the (i) population level and (ii) between-population level, we compared the Jaccard dissimilarity, nestedness and turnover of high- and low-dominance plots. Further, we calculated the Jaccard dissimilarity, nestedness and turnover between the high- and low-dominance plots within each population to express the impacts on species composition. We tested whether (i) native and invasive dominants affect the population- and between population levels of diversity by making the vegetation more homogenous; (ii) whether these effects differ between the native and alien dominants; and (iii) whether the impacts at different spatial levels are related. At the population level, high-dominance plots (with both native and alien dominants) showed higher nestedness and lower turnover compared to the low-dominance plots. Further, all plots with native dominants, both with high- and low dominance, showed higher similarity but lower nestedness than plots with alien dominants. Most importantly, high-dominance plots with native dominants were more similar to each other but showed marginally significantly lower nestedness compared to high-dominance plots with alien dominants. At the between-population level, high-dominance plots with native dominants showed a marginally significantly lower turnover compared to high-dominance plots with alien dominants. The differences in Jaccard dissimilarity, nestedness and turnover between the low- and high-dominance plots at the population level showed strong positive relations to low- and high-dominance differences at the between-populations level. Further, compositional impacts, expressed as the dissimilarity between high- vs. low-dominance plots, positively related to the plot-level impacts on Shannon diversity. Our results show that (i) both native and invasive dominants tend to reduce the diversity over larger areas and that the effect of native dominants may be even stronger, and (ii) the effects on plot-level richness and diversity cannot be easily extrapolated to larger scales but the impacts at the population- and between-populations levels are positively related.

Abstract Human factors and plant characteristics are important drivers of plant invasions, which threaten ecosystem integrity, biodiversity and human well-being. However, while previous studies often examined a limited number of factors or focused on a specific invasion stage (e.g., naturalization) for specific regions, a multi-factor and multi-stage analysis at the global scale is lacking. Here, we employ a multi-level framework to investigate the interplay between plant characteristics (genome size, Grime’s adaptive CSR-strategies and native range size) and economic use and how these factors collectively affect plant naturalization and invasion success worldwide. While our findings derived from structural equation models highlight the substantial contribution of human assistance in both the naturalization and spread of invasive plants, we also uncovered the pivotal role of species’ adaptive strategies among the factors studied, and the significantly varying influence of these factors across invasion stages. We further revealed that the effects of genome size on plant invasions were partially mediated by species adaptive strategies and native range size. Our study provides insights into the complex and dynamic process of plant invasions and identifies its key drivers worldwide.

Abstract Darwin’s naturalization conundrum describes two seemingly contradictory hypotheses regarding whether alien species closely or distantly related to native species should be more likely to naturalize in regional floras. Both expectations have accumulated empirical support, and whether such apparent inconsistency can be reconciled at the global scale is unclear. Here, using 219,520 native and 9,531 naturalized alien plant species across 487 globally distributed regions, we found a latitudinal gradient in Darwin’s naturalization conundrum. Naturalized alien plant species are more closely related to native species at higher latitudes than they are at lower latitudes, indicating a greater influence of preadaptation in harsher climates. Human landscape modification resulted in even steeper latitudinal clines by selecting aliens distantly related to natives in warmer and drier regions. Our results demonstrate that joint consideration of climatic and anthropogenic conditions is critical to reconciling Darwin’s naturalization conundrum.

Biological invasions are globally recognised as a significant threat to native biodiversity, as they can change the structure, composition, and functioning of the native ecological system. The riparian forest is considered a habitat highly invaded by invasive plants since rivers serve as corridors for alien species through the terrestrial ecosystem or may simply harbour exotic species that cannot survive elsewhere. The riparian forest, as a high conservation value forest, is an important part of the lowland forests of Georgia. These forests are distributed along large rivers, including the Mtkvari, Alazani, Iori, Aragvi, Ksani, Algeti, and Great and Little Liakhvi rivers. Here, we present a case study that was part of the scientific project titled 'Survey of Potential Invasive Alien Woody Species (PIAWS) in the Protected Areas of Georgia'. Protected areas (PAs) in Georgia play an important role in conserving native biodiversity, including forest ecosystems of distinguished biodiversity. We focused on the lowland riparian forest (LRF) distributed along the Mtkvari and Iori rivers within two PAs - Korugi and Gardabani Managed Reserves (MRs). Six main alien woody species (AWS) were identified in the study areas: Robinia pseudoacacia, Gleditsia triacanthos, Ailanthus altissima, Acer negundo, Amorpha fruticose and Morus alba. Among these AWS, the local status of R. pseudoacacia, G. triacanthos, A. altissima, and A. fruticosa is invasive, while that of A. negundo and M. alba is naturalised. The environmental impact of AWS on LRF habitat was evaluated using the Environmental Impact Classification for Alien Taxa (EICAT) classification system. A major or moderate impact of AWS on the LRF habitat is evident, which, according to EICAT impact mechanisms, is expressed as apparent competition and physical, structural and indirect impacts. The study revealed that the impact levels of three AWS, R. pseudoacacia, G. triacanthos, and A. altissima, were classified as major or moderate ('harmful' impact), while the remaining AWS, A. negundo and A. fruticosa, were of minor or minimal concern. AWS in the invaded areas of the LRF are found as an understorey layer or, otherwise, they have already formed the main canopy and replaced native dominant woody species. Therefore, undesirable structural and succession processes in invaded LRFs are evident.

ABSTRACTRecent global and regional assessments of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) show that Nature’s Contributions to People (NCP) are under an alarming threat due to the continuing loss of biodiversity. These assessments call for increasing conservation efforts and a more sustainable use of biodiversity to enhance the chances of halting biodiversity loss and reversing current trends. One of the strategies to achieve change is to mainstream biodiversity into sectoral policies. Mainstreaming, a concept that can be traced back to the Brundtland report, promotes the integration of the environment into political, societal, and economic planning and decision-making. Based on the review of key studies undertaken during the regional assessment for Europe and Central Asia, we develop a stepwise approach to analyze the current status of mainstreaming of biodiversity and NCP. The approach can be used both for policy design purposes and diagnostic evaluations. It demonstrates that mainstreaming has the potential to improve the conservation and sustainable use of biodiversity as well as the sustained provision of NCP. However, based on the status of implementation across Europe and Central Asia, we conclude that mainstreaming needs to be pursued and implemented in a stronger and more systematic way. The results of our assessment provide important input to national strategies and policies but also to the ongoing process of the Conference of the Parties to the Convention on Biological Diversity while developing the post-2020 global biodiversity framework.

Abstract While the regional distribution of non-native species is increasingly well documented for some taxa, global analyses of non-native species in local assemblages are still missing. Here, we use a worldwide collection of assemblages from five taxa - ants, birds, mammals, spiders and vascular plants - to assess whether the incidence, frequency and proportions of naturalised non-native species depend on type and intensity of land use. In plants, assemblages of primary vegetation are least invaded. In the other taxa, primary vegetation is among the least invaded land-use types, but one or several other types have equally low levels of occurrence, frequency and proportions of non-native species. High land use intensity is associated with higher non-native incidence and frequency in primary vegetation, while intensity effects are inconsistent for other land-use types. These findings highlight the potential dual role of unused primary vegetation in preserving native biodiversity and in conferring resistance against biological invasions.

Humans have altered plant biogeography by introducing species from one region to another, but an analysis of how naturalized plant species affect the uniqueness of regional floras around the world was missing. This study presents an analysis using data from native and naturalized alien floras in 658 regions, finding strong taxonomic and phylogenetic floristic homogenization overall.

Delavaux et al. uses global plant databases to examine how the types of mycorrhizal fungi influence the colonization of plants on islands. Their results show that arbuscular mycorrhizal (AM) symbiosis limits plant species’ establishment on islands more than other mycorrhizal associations, and that this initial filter of AM plant species impacts diversification and plant invasion risks.

The Pacific region has the highest density of naturalized plant species worldwide, which makes it an important area for research on the ecology, evolution and biogeography of biological invasions. While different data sources on naturalized plant species exist for the Pacific, there is no taxonomically and spatially harmonized database available for different subsets of species and islands. A comprehensive, accessible database containing the distribution of naturalized vascular plant species in the Pacific will enable new basic and applied research for researchers and will be an important information source for practitioners working in the region.Here, we present PacIFlora, an updated and taxonomically standardized list of naturalized species, their unified nativeness, cultivation and invasiveness status, and their distribution across the Pacific Ocean, including harmonized location denommination. This list is based on the two largest databases on naturalized plants for the region, specifically the Pacific Island Ecosystems at Risk (PIER) and the Global Naturalized Alien Flora (GloNAF) databases. We provide an outlook for how this database can contribute to numerous research questions and conservation efforts.

Species introduced through human-related activities beyond their native range, termed alien species, have various impacts worldwide. The IUCN Environmental Impact Classification for Alien Taxa (EICAT) is a global standard to assess negative impacts of alien species on native biodiversity. Alien species can also positively affect biodiversity (for instance, through food and habitat provisioning or dispersal facilitation) but there is currently no standardized and evidence-based system to classify positive impacts. We fill this gap by proposing EICAT+, which uses 5 semiquantitative scenarios to categorize the magnitude of positive impacts, and describes underlying mechanisms. EICAT+ can be applied to all alien taxa at different spatial and organizational scales. The application of EICAT+ expands our understanding of the consequences of biological invasions and can inform conservation decisions.

Ornamental plantations are characteristic of a wide range of man-made habitats such as gardens, parks or urban spaces. Nowadays, low-maintenance perennial beds are becoming popular in horticulture and urban planning. Due to low levels of management and good records of initial plantation, perennial beds are suitable for studying vegetation processes such as competition amongst garden ornamentals and succession. We studied perennial flowerbeds in the Czech Republic that had a known initial composition at the time of establishment in 2006–2010 and we compared this with their state in 2016. We aimed to assess (i) how planted ornamental assemblages changed during 10 years of succession, and (ii) whether initial assemblage composition determined the pattern of change. We observed a decrease in biodiversity from initial plantation to the recent state across all flowerbeds in the experimental garden. In terms of diversity and stability, species-rich assemblages, mostly composed of taxa native to prairies, were the most stable. The most successful taxa (i.e. reaching high abundances with good persistence) originated from North American and Mediterranean regions.

Sustainably managed non-native trees deliver economic and societal benefits with limited risk of spread to adjoining areas. However, some plantations have launched invasions that cause substantial damage to biodiversity and ecosystem services, while others pose substantial threats of causing such impacts. The challenge is to maximise the benefits of non-native trees, while minimising negative impacts and preserving future benefits and options. A workshop was held in 2019 to develop global guidelines for the sustainable use of non-native trees, using the Council of Europe – Bern Convention Code of Conduct on Invasive Alien Trees as a starting point. The global guidelines consist of eight recommendations: 1) Use native trees, or non-invasive non-native trees, in preference to invasive non-native trees; 2) Be aware of and comply with international, national, and regional regulations concerning non-native trees; 3) Be aware of the risk of invasion and consider global change trends; 4) Design and adopt tailored practices for plantation site selection and silvicultural management; 5) Promote and implement early detection and rapid response programmes; 6) Design and adopt tailored practices for invasive non-native tree control, habitat restoration, and for dealing with highly modified ecosystems; 7) Engage with stakeholders on the risks posed by invasive non-native trees, the impacts caused, and the options for management; and 8) Develop and support global networks, collaborative research, and information sharing on native and non-native trees. The global guidelines are a first step towards building global consensus on the precautions that should be taken when introducing and planting non-native trees. They are voluntary and are intended to complement statutory requirements under international and national legislation. The application of the global guidelines and the achievement of their goals will help to conserve forest biodiversity, ensure sustainable forestry, and contribute to the achievement of several Sustainable Development Goals of the United Nations linked with forest biodiversity.

The number of alien species arriving within new regions has increased at unprecedented rates. Managing the pathways through which alien species arrive and spread is important to reduce the threat of biological invasions. Harmonising information on pathways across individual sectors and user groups is therefore critical to underpin policy and action. The European Alien Species Information Network (EASIN) has been developed to easily facilitate open access to data of alien species in Europe. The Convention on Biological Diversity (CBD) Pathway Classification framework has become a global standard for the classification of pathways. We followed a structured approach to assign pathway information within EASIN for a subset of alien species in Europe, which covered 4169 species, spanning taxonomic groups and environments. We document constraints and challenges associated with implementing the CBD Pathway Classification framework and propose potential amendments to increase clarity. This study is unique in the scope of taxonomic coverage and also in the inclusion of primary (independent introductions to Europe) and secondary (means of dispersal for species expansion within Europe, after their initial introduction) modes of introduction. In addition, we summarise the patterns of introduction pathways within this subset of alien species within the context of Europe. Based on the analyses, we confirm that the CBD Pathway Classification framework offers a robust, hierarchical system suitable for the classification of alien species introduction and spread across a wide range of taxonomic groups and environments. However, simple modifications could improve interpretation of the pathway categories ensuring consistent application across databases and information systems at local, national, regional, continental and global scales. Improving consistency would also help in the development of pathway action plans, as required by EU legislation.

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.

Understanding why certain alien species become naturalized can shed light on biological invasion patterns. In this global analysis on thousands of taxa, van Kleunen and colleagues show that plant species of economic use are more likely to become naturalized, and that this underlies geographic patterns and phylogenetic signals in naturalization

Establishing and managing protected areas (national parks, nature reserves and other sites of conservation value) represent the most common approach to conserving species and ecosystems, but these areas are vulnerable to global environmental change. Recently, Golden Kroner et al. (2019) suggested protected area downgrading, downsizing, and degazettement (PADDD) as one of the main threats to biodiversity conservation. However, there are several other elements, of similar concern, that threaten conservation efforts in protected areas, such as climate change and pollution. Here, in a commentary to the Golden Kroner et al. (2019) paper, we address an additional important element affecting protected area dynamics and robustness that was overlooked by these authors – invasions by alien species. We argue that invasive alien species (IAS) contribute directly to the pressures of biodiversity loss by competing with native species and modifying the characteristics of the invaded ecosystems, and virtually no protected areas are free from these effects. Therefore, excluding IAS from legal instruments and policy frameworks underpinning current conservation approaches in protected areas presents a great risk for nature conservation. Consequently, this aligns poorly with the idea of protected areas being a cornerstone for conservation at local, regional and national levels. For that reason and to paint a more complete picture of the effectiveness of protected areas, we argue that when other factors threatening the existence and functioning of protected areas are discussed, we also need to account for biological invasions. This will ensure that adaptive conservation management strategies protect a wide range of species, ecosystems, and landscapes. Hence, this commentary aims to be of general interest for policymakers, managers and researchers.

not for this short letter

Ornamental plants are an important component of urban floras and a significant source of alien plant invasions to the surrounding landscapes. We studied ornamental flora across 174 settlements in the Czech Republic, Central Europe. The aims of the study were to (i) identify clusters of sites that are defined as distinctive groups of ornamental taxa reflecting environmental or socioeconomic factors and (ii) apply the classification approach which is traditionally used for spontaneous vegetation in order to evaluate the potential of different settlement types to act as source sites of invasive species. The inventories were classified in a similar manner that is generally applied to spontaneous vegetation using the COCKTAIL method. Diagnostic taxa were classified in a repeatable manner into 17 species groups, forming five distinctive clusters with ~70% of sites attributed to one cluster. The species pools of the clusters differed in their representation of species with native or alien status and different life forms. The following clusters were distinguished, based on the prevailing type of settlement: (1) old villas neighbourhoods of towns, (2) upland settlements, (3) modern neighbourhoods, (4) old rustic settlements and (5) modern rustic settlements. Similar to spontaneous vegetation, the classification of ornamental flora reflects both basic natural gradients (i.e. altitude) and man-made factors (i.e. the preferences for certain plants and associated management practices). Alien taxa associated with modern neighbourhoods are characterised by a relatively higher invasion potential than those from, for example, old rustic settlements. This is especially true for woody species which can spread in ruderal habitats as a result of urban sprawl. Our results showed that the classification method, commonly used to analyse vegetation data, can also be applied to ornamental flora.

Standardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.

Island species and habitats are particularly vulnerable to human disturbances, and anthropogenic changes are increasingly overwriting natural island biogeographic patterns. However, quantitative comparisons of how native and alien assemblages respond to human disturbances are scarce. Using data from 6,242 species of vertebrates, invertebrates and plants, from 7,718 sites on 81 islands, we model how land-use change, human population density and distance to the nearest road affect local assemblages of alien and native species on islands. We found that land-use change reduces both richness and abundance of native species, whereas the number and abundance of alien species are high in plantation forests and agricultural or urban sites. In contrast to the long-established pattern for native species (i.e., decline in species number with island isolation), more isolated islands have more alien species across most land uses than do less isolated islands. We show that alien species play a major role in the turnover of island assemblages: our models show that aliens outnumber natives among the species present at disturbed sites but absent from minimally-disturbed primary vegetation. Finally, we found a homogenization pattern for both native and alien assemblages across sites within most land uses. The declines of native species on islands in the face of human pressures, and the particular proneness to invasions of the more remote islands, highlight the need to reduce the intensity of human pressures on islands and to prevent the introduction and establishment of alien species.

There is no sign of saturation in accumulation of alien species (AS) introductions worldwide, additionally the rate of spread for some species has also been shown to be increasing. However, the challenges of gathering information on AS are recognized. Recent developments in citizen science (CS) provide an opportunity to improve data flow and knowledge on AS while ensuring effective and high quality societal engagement with the issue of IAS (Invasive Alien Species). Advances in technology, particularly on-line recording and smartphone apps, along with the development of social media, have revolutionized CS and increased connectivity while new and innovative analysis techniques are emerging to ensure appropriate management, visualization, interpretation and use and sharing of the data. In early July 2018 we launched a European CO-operation in Science and Technology (COST) Action to address multidisciplinary research questions in relation to developing and implementing CS, advancing scientific understanding of AS dynamics while informing decision-making specifically implementation of technical requirements of relevant legislation such as the EU Regulation 1143/2014 on IAS. It will also support the EU biodiversity goals and embedding science within society. The Action will explore and document approaches to establishing a European-wide CS AS network. It will embrace relevant innovations for data gathering and reporting to support the implementation of monitoring and surveillance measures, while ensuring benefits for society and citizens, through an AS CS European network. The Action will, therefore, increase levels of participation and quality of engagement with current CS initiatives, ensuring and evaluating educational value, and improve the value outcomes for potential users including citizens, scientists, alien species managers, policy-makers, local authorities, industry and other stakeholders.

Quantitative data on local variation in patterns of occurrence of common carnivore species, such as the red fox, European badger, or martens in central Europe are largely missing. We conducted a study focusing on carnivore ecology and distribution in a cultural landscape with the use of modern technology. We placed 73 automated infra-red camera traps into four different habitats differing in water availability and canopy cover (mixed forest, wetland, shrubby grassland and floodplain forest) in the Polabí region near Prague, Czech Republic. Each habitat was represented by three or four spatially isolated sites within which the camera traps were distributed. During the year of the study, we recorded nine carnivore species, including the non-native golden jackal. Habitats with the highest numbers of records pooled across all species were wetland (1279) and shrubby grassland (1014); fewer records were made in mixed (876) and floodplain forest (734). Habitat had a significant effect on the number of records of badger and marten, and a marginally significant effect on fox. In terms of seasonal dynamics, there were significant differences in the distribution of records among seasons in fox, marginally significant in least weasel, and the occurrence among seasons did not differ for badger and marten. In the summer, fox and marten were more active than expected by chance during the day, while the pattern was opposite in winter when they were more active during the night. Our findings on habitat preferences and circadian and seasonal activity provided the first quantitative data on patterns whose existence was assumed on the basis of conventional wisdom. Our study demonstrates the potential of a long-term monitoring approach based on infra-red camera traps. Generally, the rather frequent occurrence of recorded species indicates that most carnivore species are thriving in current central-European landscapes characterized by human-driven disturbances and urbanization.

In this paper, we present the impact categorizations of 51 alien plant species in Turkey, which were determined using the Generic Impact Scoring System (GISS). The evidence on environmental and socioeconomic impacts of these alien species was searched in literature. Impacts were classified into 12 categories (six for environmental and six for socioeconomic) and, within each category, the impact was assessed on a six degree scale. Environmental impacts were recorded for 80% of the species and mostly concern ecosystem processes (changes in nutrient or water availability and disturbance regimes), while socioeconomic impacts, identified for 78% of the species assessed, are typically associated with agricultural production or human health. Summed scores of individual species across categories of environmental and socioeconomic impacts were not significantly correlated. By taking into account the actual distribution of the assessed species, we evaluated the regional distribution of (potential) impacts in Turkey. The Black Sea region harbours the highest number of species with impacts (34 species, i.e. 67% of the total assessed for the whole country), 28 species were recorded in the Marmara, 21 in the Mediterranean, 17 in the Aegean and 12 in each of the South East Anatolia, Central Anatolia and East Anatolia regions. The species that have negative impact on forestry are only found in three regions. Altogether 21 species are agricultural weeds, but we only found evidence of a minor socioeconomic impact for some of them. Determining the impacts based on specific criteria (i) provides basis for objective risk assessment of plant invasions in Turkey, (ii) can be taken as early warning to combat these plants and (iii) contributes to the growing body of evidence of the impacts of alien plant species.

Abstract According to the Convention on Biological Diversity, by 2020 invasive alien species (IAS) should be identified and their impacts assessed, so that species can be prioritized for implementation of appropriate control strategies and measures put in place to manage invasion pathways. For one quarter of the IAS listed as the “100 of the world's worst” environmental impacts are linked to diseases of wildlife (undomesticated plants and animals). Moreover, IAS are a significant source of “pathogen pollution” defined as the human‐mediated introduction of a pathogen to a new host or region. Despite this, little is known about the biology of alien pathogens and their biodiversity impacts after introduction into new regions. We argue that the threats posed by alien pathogens to endangered species, ecosystems, and ecosystem services should receive greater attention through legislation, policy, and management. We identify 10 key areas for research and action, including those relevant to the processes of introduction and establishment of an alien pathogen and to prediction of the spread and associated impact of an alien pathogen on native biota and ecosystems. The development of interdisciplinary capacity, expertise, and coordination to identify and manage threats was seen as critical to address knowledge gaps.

Robinia pseudoacacia L. (black locust) is a North American tree, considered controversial because of the conflict between multiple uses by humans and negative environmental impacts, which have resulted in it being listed among the most invasive species in Europe. The current management of Robinia stands in Central Europe varies locally according to national legislation, preferring either socio-economic benefits or biodiversity impacts. We collected field data from our target region of Czechia, reviewed research articles including local grey literature mostly from Central and Southern Europe, unpublished results of local projects and inquired relevant specialists. Because Robinia grows in habitats ranging from urban to forest to natural grassland, neither unrestricted cultivation nor large-scale eradication is applicable as a universal practice. In this paper we suggest a complex management strategy for Robinia stands that takes into account habitat, this species’ local ability to spread, as well as economic, cultural and biodiversity aspects. We categorized Robinia stands growing in Europe into eight groups and proposed stratified approach to the management based on decisions that reflect local context. Depending on that, the management includes (i) establishment of new plantations, (ii) maintenance or utilization of existing stands, (iii) tolerance and (iv) conversion to original vegetation. Our complex management strategy will provide a comprehensive guideline for the management of alien trees in Europe.

The paper provides an updated checklist of the alien flora of Turkey with information on its structure. The alien flora of Turkey comprises 340 taxa, among which there are 321 angiosperms, 17 gymnosperms and two ferns. Of the total number of taxa, 228 (68%) are naturalized and 112 (32%) are casual. There are 275 neophytes (172 naturalized and 103 casual) and 61 archaeophytes (52 naturalized and 9 casual); four species could not be classified with respect to the residence time. In addition, 47 frequently planted taxa with a potential to escape are also listed. The richest families are Asteraceae (38 taxa), Poaceae (30), Fabaceae (23) and Solanaceae (22). As for the naturalized alien plants, the highest species richness is found in Asteraceae (31 taxa), Poaceae (22), Amaranthaceae (18) and Solanaceae (15). The majority of alien taxa are perennial (63.8% of the total number of taxa with this life history assigned, including those with multiple life histories), annuals contribute 33.8% and 2.4% are biennial aliens. Among perennials the most common life forms are phanerophytes, of which 20.3% are trees and 12.6% shrubs; woody vines, stem succulents, and aquatic plants are comparatively less represented. Most of the 340 alien taxa introduced to Turkey have their native ranges in Americas (44.7%) and Asia (27.6%). Of other regions, 9.1% originated in Africa, 4.4% in Eurasia, 3.8% in Australia and Oceania and 3.5% in the Mediterranean. The majority of taxa (71.9%) were introduced intentionally, whereas the remaining (28.1%) were introduced accidentally. Among the taxa introduced intentionally, the vast majority are ornamental plants (55.2%), 10.0% taxa were introduced for forestry and 6.7% as crops. Casual alien plants are most commonly found in urban and ruderal habitats (40.1%) where naturalized taxa are also often recorded (27.3%). Plants that occur as agricultural weeds are typically naturalized rather than casual (16.0% vs 7.1%, respectively). However, (semi)natural habitats in Turkey are often invaded by alien taxa, especially by those that are able to naturalize.

Alien species of animals and plants can invade new regions of the earth. This study performs a global analysis of temporal dynamics and spatial patterns of alien species introductions over the past 200 years, and reports no saturation in the rate at which these invasion are increasing.

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.

Abstract Mycorrhizal symbiosis has received relatively little attention as a mechanism explaining plant naturalizations at a global scale. Here, we combined data on vascular plant species occurrences in over 840 mainland and island regions from the Global Naturalized Alien Flora (GloNAF) database with up‐to‐date databases of mycorrhizal associations. We tested whether the mycorrhizal type (arbuscular, AM; ectomycorrhizal, ECM; and non‐mycorrhizal, NM) and status (facultative and obligate) were associated with two measures of naturalization success, (1) naturalization incidence (reflecting the ability to naturalize, and expressed as whether or not a plant species is recorded as naturalized anywhere in the world) and (2) naturalization extent (expressed as the number of GloNAF regions where the species occurs). In total, we found information on mycorrhizal type and status for 3211 naturalized plant species and 4200 non‐naturalized plant species. Mycorrhizal plant species, both AM and ECM, were more likely to be naturalized and naturalized to a greater extent than NM plants. The effect of being an AM species was always stronger, with AM species having a greater naturalization extent than ECM species. Being the same mycorrhizal type or status, annual species were generally more likely to be naturalized than perennials. Species with facultative mycorrhizal associations were more successful than those with obligate mycorrhizal associations, but both groups tended to have a greater chance of being naturalized than NM species. These results indicate that being NM is generally less favorable for naturalization. Overall, our results confirm, at the global scale, those of regional studies that facultative association with AM provides plant species with a naturalization advantage. For the first time, we have shown that being mycorrhizal contributes not only to the size of the naturalized range, reflecting the ability to spread, but also to the ability to become naturalized in the first instance.

Abstract Most studies on the impacts of plant invasions focus on species richness or diversity of invaded communities, but much less attention has been paid to structural changes such as the representation of species with different traits. To bridge this knowledge gap, we assess the impact of dominant species on the trait composition of recipient communities (i.e., how species with certain height, seed mass, specific leaf area, clonality, and life form are represented in the vegetation plots sampled). We sampled vegetation that comprised three species native to Eurasia and invasive in North America (i.e., Agrostis capillaris, Bromus tectorum, and Cirsium arvense) and three species native to North America and invasive in Europe (i.e., Aster novi‐belgii, Lupinus polyphyllus, and Solidago canadensis), in both their native and invaded ranges. This study system based on reciprocal inter‐continental invasions allowed us to assess whether the impact on trait composition differed (1) between the native and invaded ranges and (2) between the two continents. The relationships between species’ dominance and trait composition were tested using linear mixed‐effect models and ordination methods. A general trend was that dominant species with an impact on species richness also had an impact on trait composition, especially in North America, where even the native dominants affected the trait composition of the community. Further, the impact of Eurasian dominants in North America was stronger than that associated with the opposite direction of invasion, due to a strong negative effect of Eurasian invaders on local tall clonal perennials. Our results show that (1) the traits of species in the invaded community co‐determine the impact of invasion and are related to the impacts on species richness and composition; (2) the impacts on trait composition differ between the native and invaded ranges; and (3) the direction of invasion affects the impact on trait composition.

Plants with the capability to reproduce easily without mates and pollinators could have an advantage when colonizing new territory. Here, Razanajatovoet al. use a global database to infer that flowering plants capable of selfing have become naturalized in a larger number of regions than those that must outcross.

Science-based strategies to tackle biological invasions depend on recent, accurate, well-documented, standardized and openly accessible information on alien species. Currently and historically, biodiversity data are scattered in numerous disconnected data silos that lack interoperability. The situation is no different for alien species data, and this obstructs efficient retrieval, combination, and use of these kinds of information for research and policy-making. Standardization and interoperability are particularly important as many alien species related research and policy activities require pooling data. We describe seven ways that data on alien species can be made more accessible and useful, based on the results of a European Cooperation in Science and Technology (COST) workshop: (1) Create data management plans; (2) Increase interoperability of information sources; (3) Document data through metadata; (4) Format data using existing standards; (5) Adopt controlled vocabularies; (6) Increase data availability; and (7) Ensure long-term data preservation. We identify four properties specific and integral to alien species data (species status, introduction pathway, degree of establishment, and impact mechanism) that are either missing from existing data standards or lack a recommended controlled vocabulary. Improved access to accurate, real-time and historical data will repay the long-term investment in data management infrastructure, by providing more accurate, timely and realistic assessments and analyses. If we improve core biodiversity data standards by developing their relevance to alien species, it will allow the automation of common activities regarding data processing in support of environmental policy. Furthermore, we call for considerable effort to maintain, update, standardize, archive, and aggregate datasets, to ensure proper valorization of alien species data and information before they become obsolete or lost.

To better understand the effect of species traits on plant invasion, we collected comparative data on 20 reproductive and dispersal traits of 93 herbaceous alien species in the Czech Republic, central Europe, introduced after 1500 A. D. We explain plant invasion success, expressed by two measures: invasiveness, i.e. whether the species is naturalized but non-invasive, or invasive; and dominance in plant communities expressed as the mean cover in vegetation plots. We also tested how important reproductive and dispersal traits are in models including other characteristics generally known to predict invasion outcome, such as plant height, life history and residence time. By using regression/classification trees we show that the biological traits affect invasion success at all life stages, from reproduction (seed production) to dispersal (propagule properties), and the ability to compete with resident species (height). By including species traits information not usually available in multispecies analyses, we provide evidence that traits do play important role in determining the outcome of invasion and can be used to distinguish between alien species that reach the final stage of the invasion process and dominate the local communities from those that do not. No effect of taxonomy ascertained in regression and classification trees indicates that the role of traits in invasiveness should be assessed primarily at the species level.

Species moved by human activities beyond the limits of their native geographic ranges into areas in which they do not naturally occur (termed aliens) can cause a broad range of significant changes to recipient ecosystems; however, their impacts vary greatly across species and the ecosystems into which they are introduced. There is therefore a critical need for a standardised method to evaluate, compare, and eventually predict the magnitudes of these different impacts. Here, we propose a straightforward system for classifying alien species according to the magnitude of their environmental impacts, based on the mechanisms of impact used to code species in the International Union for Conservation of Nature (IUCN) Global Invasive Species Database, which are presented here for the first time. The classification system uses five semi-quantitative scenarios describing impacts under each mechanism to assign species to different levels of impact-ranging from Minimal to Massive-with assignment corresponding to the highest level of deleterious impact associated with any of the mechanisms. The scheme also includes categories for species that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. We show how this classification system is applicable at different levels of ecological complexity and different spatial and temporal scales, and embraces existing impact metrics. In fact, the scheme is analogous to the already widely adopted and accepted Red List approach to categorising extinction risk, and so could conceivably be readily integrated with existing practices and policies in many regions.

Although issues related to the management of invasive alien species are receiving increasing attention, little is known about which factors affect the likelihood of success of management measures. We applied two data mining techniques, classification trees and boosted trees, to identify factors that relate to the success of management campaigns aimed at eradicating invasive alien invertebrates, plants and plant pathogens. We assembled a dataset of 173 different eradication campaigns against 94 species worldwide, about a half of which (50.9%) were successful. Eradications in man-made habitats, greenhouses in particular, were more likely to succeed than those in (semi-)natural habitats. In man-made habitats the probability of success was generally high in Australasia, while in Europe and the Americas it was higher for local infestations that are easier to deal with, and for international campaigns that are likely to profit from cross-border cooperation. In (semi-) natural habitats, eradication campaigns were more likely to succeed for plants introduced as an ornamental and escaped from cultivation prior to invasion. Averaging out all other factors in boosted trees, pathogens, bacteria and viruses were most, and fungi the least likely to be eradicated; for plants and invertebrates the probability was intermediate. Our analysis indicates that initiating the campaign before the extent of infestation reaches the critical threshold, starting to eradicate within the first four years since the problem has been noticed, paying special attention to species introduced by the cultivation pathway, and applying sanitary measures can substantially increase the probability of eradication success. Our investigations also revealed that information on socioeconomic factors, which are often considered to be crucial for eradication success, is rarely available, and thus their relative importance cannot be evaluated. Future campaigns should carefully document socioeconomic factors to enable tests of their importance.

Many distribution models developed to predict the presence/absence of invasive alien species need to be fitted to a training dataset before practical use. The training dataset is characterized by the number of recorded presences/absences and by their geographical locations. The aim of this paper is to study the effect of the training dataset characteristics on model performance and to compare the relative importance of three factors influencing model predictive capability; size of training dataset, stage of the biological invasion, and choice of input variables. Nine models were assessed for their ability to predict the distribution of the western corn rootworm, Diabrotica virgifera virgifera, a major pest of corn in North America that has recently invaded Europe. Twenty-six training datasets of various sizes (from 10 to 428 presence records) corresponding to two different stages of invasion (1955 and 1980) and three sets of input bioclimatic variables (19 variables, six variables selected using information on insect biology, and three linear combinations of 19 variables derived from Principal Component Analysis) were considered. The models were fitted to each training dataset in turn and their performance was assessed using independent data from North America and Europe. The models were ranked according to the area under the Receiver Operating Characteristic curve and the likelihood ratio. Model performance was highly sensitive to the geographical area used for calibration; most of the models performed poorly when fitted to a restricted area corresponding to an early stage of the invasion. Our results also showed that Principal Component Analysis was useful in reducing the number of model input variables for the models that performed poorly with 19 input variables. DOMAIN, Environmental Distance, MAXENT, and Envelope Score were the most accurate models but all the models tested in this study led to a substantial rate of mis-classification.

BACKGROUND: Understanding the dimensions of pathways of introduction of alien plants is important for regulating species invasions, but how particular pathways differ in terms of post-invasion success of species they deliver has never been rigorously tested. We asked whether invasion status, distribution and habitat range of 1,007 alien plant species introduced after 1500 A.D. to the Czech Republic differ among four basic pathways of introduction recognized for plants. PRINCIPAL FINDINGS: Pathways introducing alien species deliberately as commodities (direct release into the wild; escape from cultivation) result in easier naturalization and invasion than pathways of unintentional introduction (contaminant of a commodity; stowaway arriving without association with it). The proportion of naturalized and invasive species among all introductions delivered by a particular pathway decreases with a decreasing level of direct assistance from humans associated with that pathway, from release and escape to contaminant and stowaway. However, those species that are introduced via unintentional pathways and become invasive are as widely distributed as deliberately introduced species, and those introduced as contaminants invade an even wider range of seminatural habitats. CONCLUSIONS: Pathways associated with deliberate species introductions with commodities and pathways whereby species are unintentionally introduced are contrasting modes of introductions in terms of invasion success. However, various measures of the outcome of the invasion process, in terms of species' invasion success, need to be considered to accurately evaluate the role of and threat imposed by individual pathways. By employing various measures we show that invasions by unintentionally introduced plant species need to be considered by management as seriously as those introduced by horticulture, because they invade a wide range of seminatural habitats, hence representing even a greater threat to natural areas.

Assessing the distribution of geographically restricted and evolutionarily unique species and their underlying drivers is key to understanding biogeographical processes and critical for global conservation prioritization. Here, we quantified the geographic distribution and drivers of phylogenetic endemism for ~320,000 seed plants worldwide and identified centers and drivers of evolutionarily young (neoendemism) and evolutionarily old endemism (paleoendemism). Tropical and subtropical islands as well as tropical mountain regions displayed the world’s highest phylogenetic endemism. Most tropical rainforest regions emerged as centers of paleoendemism, while most Mediterranean-climate regions showed high neoendemism. Centers where high neo-and paleoendemism coincide emerged on some oceanic and continental fragment islands, in Mediterranean-climate regions and parts of the Irano-Turanian floristic region. Global variation in phylogenetic endemism was well explained by a combination of past and present environmental factors (79.8 to 87.7% of variance explained) and most strongly related to environmental heterogeneity. Also, warm and wet climates, geographic isolation, and long-term climatic stability emerged as key drivers of phylogenetic endemism. Neo-and paleoendemism were jointly explained by climatic and geological history. Long-term climatic stability promoted the persistence of paleoendemics, while the isolation of oceanic islands and their unique geological histories promoted neoendemism. Mountainous regions promoted both neo-and paleoendemism, reflecting both diversification and persistence over time. Our study provides insights into the evolutionary underpinnings of biogeographical patterns in seed plants and identifies the areas on Earth with the highest evolutionary and biogeographical uniqueness—key information for setting global conservation priorities. [ABSTRACT FROM AUTHOR]