A Source Area Approach Demonstrates Moderate Predictive Ability but Pronounced Variability of Invasive Species Traits

The search for traits that make alien species invasive has mostly concentrated on comparing successful invaders and different comparison groups with respect to average trait values. By contrast, little attention has been paid to trait variability among invaders. Here, we combine an analysis of trait differences between invasive and non-invasive species with a comparison of multidimensional trait variability within these two species groups. We collected data on biological and distributional traits for 1402 species of the native, non-woody vascular plant flora of Austria. We then compared the subsets of species recorded and not recorded as invasive aliens anywhere in the world, respectively, first, with respect to the sampled traits using univariate and multiple regression models; and, second, with respect to their multidimensional trait diversity by calculating functional richness and dispersion metrics. Attributes related to competitiveness (strategy type, nitrogen indicator value), habitat use (agricultural and ruderal habitats, occurrence under the montane belt), and propagule pressure (frequency) were most closely associated with invasiveness. However, even the best multiple model, including interactions, only explained a moderate fraction of the differences in invasive success. In addition, multidimensional variability in trait space was even larger among invasive than among non-invasive species. This pronounced variability suggests that invasive success has a considerable idiosyncratic component and is probably highly context specific. We conclude that basing risk assessment protocols on species trait profiles will probably face hardly reducible uncertainties

A High-Resolution Map of Emerald Ash Borer Invasion Risk for Southern Central Europe

Ash species (Fraxinus spp.) in Europe are threatened by the Emerald Ash Borer (Agrilus planipennis, EAB), an invasive wood boring beetle native to East Asia and currently spreading from European Russia westwards. Based on a high-resolution habitat distribution map (grid cell size: 25 × 25 m) and data on distribution and abundance of Common Ash (Fraxinus excelsior), the most widespread and highly susceptive host species of EAB in Europe, we assess the spatial distribution of EAB invasion risks for southern Central Europe (Austria, Switzerland, Liechtenstein, southern Germany, South Tyrol). We found highest F. excelsior abundance and thus invasion risks in extensive lowland floodplain forests, medium risks in zonal lowland forests and low risks in upper montane and subalpine forests. Based on average velocities of spread in Russia (13–31 km/year) and North America (2.5–80 km/year) from flight and human-assisted transport, EAB is likely to cover the distance (1500 km) between its current range edge in western Russia and the eastern border of the study region within few decades. However, secondary spread by infested wood products make earlier introductions likely. The high susceptibility and mortality of F. excelsior leave no doubt that this beetle will become a major forest pest once it reaches Central Europe. Therefore, developing and testing management approaches with the aim to halt or at least slow down the invasion of EAB in Europe have to be pursued with great urgency

Invasive alien pests threaten the carbon stored in Europe’s forests

Forests mitigate climate change by sequestering large amounts of carbon (C). However, forest C storage is not permanent, and large pulses of tree mortality can thwart climate mitigation efforts. Forest pests are increasingly redistributed around the globe. Yet, the potential future impact of invasive alien pests on the forest C cycle remains uncertain. Here we show that large parts of Europe could be invaded by five detrimental alien pests already under current climate. Climate change increases the potential range of alien pests particularly in Northern and Eastern Europe. We estimate the live C at risk from a potential future invasion as 1027 Tg C (10% of the European total), with a C recovery time of 34 years. We show that the impact of introduced pests could be as severe as the current natural disturbance regime in Europe, calling for increased efforts to halt the introduction and spread of invasive alien species.© The Author(s) 201

Evidence for changes in the occurrence, frequency or severity of human health impacts resulting from exposure to alien species in Europe: a systematic map

Background: Alien species are frequently considered a serious environmental threat but negative impacts on human health through injury, allergy, or as vectors of disease sometimes have the most dire consequences for human livelihoods. Climate change and the increasing magnitude and frequency of introductions of species across geographic barriers as a result of international trade are likely to change their establishment, spread, abundance, physiology or phenology, potentially also altering their human health impacts. Yet despite receiving increasing attention in the scientific literature, there have been few attempts to quantify recent changes in human health impacts. Here we report the findings from a systematic map of the literature identifying evidence of any change in the occurrence, frequency or severity of impacts of alien species on human health in Europe over the last 25 years. Methods: We conducted a systematic search of the ecological and medical literature using English language search terms to identify potentially relevant studies. Search results were assessed against inclusion criteria published in an a priori protocol at title, abstract and full-text to determine their suitability for inclusion in the review. Repeatability was checked at each stage by comparing a subset between reviewers and testing for inter-rater agreement using Cohen’s kappa test. Studies deemed relevant at full text were coded against bibliographic, inclusion and study design criteria to create a searchable database of evidence. Results: Searches retrieved over 15,700 results yet only sixteen cases met criteria for inclusion in the systematic map. Most of this evidence represents first records of impacts from different areas, and in particular first reports of transmission of exotic diseases by introduced mosquito species. Conclusions: There is currently limited published evidence demonstrating a change in the occurrence, frequency or severity of human health impacts caused by alien species in Europe over the last 25 years. Relevant studies relate to only a few species, often report specific cases and rarely link health impacts with ecology, distribution or spread of the species. Difficulties in attributing human health impacts, such as stings or allergies, to a specific alien species likely complicate attempts to measure changes, as may differences in professional interests between the environmental and health professions. Future studies could helpfully compare spread or abundance with reported, rather than potential, health impacts. Better cooperation between invasion ecologists and health professionals working in affected areas are likely to be necessary to improve the evidence base on this topic for the future.© The Author(s) 201

Hiking trails as conduits for the spread of non-native species in mountain areas

Roadsides are major pathways of plant invasions in mountain regions. However, the increasing importance of tourism may also turn hiking trails into conduits of non-native plant spread to remote mountain landscapes. Here, we evaluated the importance of such trails for plant invasion in five protected mountain areas of southern central Chile. We therefore sampled native and non-native species along 17 trails and in the adjacent undisturbed vegetation. We analyzed whether the number and cover of non-native species in local plant assemblages is related to distance to trail and a number of additional variables that characterize the abiotic and biotic environment as well as the usage of the trail. We found that non-native species at higher elevations are a subset of the lowland source pool and that their number and cover decreases with increasing elevation and with distance to trails, although this latter variable only explained 4–8% of the variation in the data. In addition, non-native richness and cover were positively correlated with signs of livestock presence but negatively with the presence of intact forest vegetation. These results suggest that, at least in the region studied, hiking trails have indeed fostered non-native species spread to higher elevations, although less efficiently than roadsides. As a corollary, appropriate planning and management of trails could become increasingly important to control plant invasions into mountains in a world which is warming and where visitation and recreational use of mountainous areas is expected to increase.(c) The Author(s) 201

What evidence exists for changes in the occurrence, frequency or severity of human health impacts resulting from exposure to alien invasive species in Europe? A systematic map protocol

Background: Invasive alien species are of global concern due to their impacts on biodiversity, related ecosystem services and on economy. A number of invasive alien species are also responsible for human health impacts, either as carriers (vectors) of pathogens, as causal agents of toxic or allergic reactions (e.g. to pollen or insect stings) or injuries. However, there has been relatively little attention given to these human health effects in invasion ecology literature, with no attempts to systematically identify and quantify evidence of impacts. It is likely that further invasive alien species will benefit from global change as some invasive traits provide high plasticity and therefore support adaptation capacities to cope with changing conditions. Thus, global change may lead to new public health concerns as invasive alien species expand their range or enter new areas, or may alter the severity of health impacts by changing the physiology or quantity of potential allergens or irritants produced. This mapping review aims at identifying any evidence for changes in the occurrence, frequency or severity of human health impacts resulting from exposure to invasive alien species in Europe over the last 25 years. Methods/Design: A systematic search of both ecological and medical literature will be used to identify potentially relevant studies using three a priori inclusion criteria, i.e. (i) affected human population in Europe, (ii) exposure to alien species, (iii) change in health impact. Studies will be assessed against inclusion criteria at title, abstract and full text to determine relevance to the mapping review. Studies deemed relevant will be coded using predetermined categories relating to the review inclusion criteria and study design, and recorded in a searchable database. Depending on the information available, studies may also be geo-referenced to create a geographic map of the evidence. Descriptive statistics will be used to explore key trends in the evidence base. The searchable database of studies and their main characteristics will be made available with the final report. It is intended that this systematic map will be useful in informing decision making related to the future human health impacts of invasive alien species in Europe

Alien Species and Human Health: Austrian Stakeholder Perspective on Challenges and Solutions

No saturation in the introduction, acceleration of spread and the increasing impacts of alien species are a characteristic feature of the Anthropocene. Concomitantly, alien species affecting human health are supposed to increase, mainly due to increasing global trade and climate change. In this study, we assess challenges and solutions posed by such species to the public health sector in Austria over the next few decades. We did so using an online questionnaire circulated to 131 experts and stakeholders working on human health and biological invasions, supplemented by in-depth interviews with eleven selected experts. Results from the online survey and in-depth interviews largely support and complement each other. Experts and stakeholders suggest that (i) the allergenic Ambrosia artemisiifolia (common ragweed), the photodermatoxic Heracleum mantegazzianum (giant hogweed), and vectors of diseases such as Aedes albopictus (Asian tiger mosquito) are considered the alien species posing the most severe challenges; (ii) challenges are expected to increase in the next few decades and awareness in the public health sector is not sufficient; (iii) effective and efficient solutions are mainly related to prevention. Specific solutions include pathway management of introduction and spread by monitoring and controlling established populations of ragweed, hogweed and mosquitos.© 2018 by the author

Plants capable of selfing are more likely to become naturalized

Many plant species have established self-sustaining populations outside their natural range because of human activities. Plants with selfing ability should be more likely to establish outside their historical range because they can reproduce from a single individual when mates or pollinators are not available. Here, we compile a global breeding-system database of 1,752 angiosperm species and use phylogenetic generalized linear models and path analyses to test relationships between selfing ability, life history, native range size and global naturalization status. Selfing ability is associated with annual or biennial life history and a large native range, which both positively correlate with the probability of naturalization. Path analysis suggests that a high selfing ability directly increases the number of regions where a species is naturalized. Our results provide robust evidence across flowering plants at the global scale that high selfing ability fosters alien plant naturalization both directly and indirectly

Effectiveness of management interventions for control of invasive Common ragweed Ambrosia artemisiifolia: a systematic review protocol

Background: Alien species are severely impacting the environment, public health and socioeconomy at a global scale. Their management is thus of crucial importance and the subject of intensive research efforts. Common ragweed Ambrosia artemisiifolia L. is an alien species with negative impacts on agriculture, human health and biodiversity. It is a highly allergenic, wind-pollinated herb native to North America that was first introduced to Europe during the seventeenth century. It has since become widespread and is currently in an ongoing phase of rapid spread and increasing abundance. Several management approaches are currently implemented and effective control of the species can have strong socioeconomic benefits. However, evidence for management effectiveness is scattered and has not yet been synthesised systematically. For these reasons, we here aim to systematically review the evidence to assess (a) what is the effectiveness of management options used for control of Common ragweed Ambrosia artemisiifolia and (b) what is the effect of confounding factors such as habitat, climate and frequency and timing of treatment? Methods: This protocol specifies the methods for conducting a systematic review to answer the specified questions. Search terms relating to the population and the intervention (type of management) will be combined and searched in a range of databases and other sources. Specific inclusion criteria are (i) any population of Ambrosia artemisiifolia at any habitat including populations in agricultural settings and such used for experimental research at any geographic location (including its native range), (ii) any physical, chemical, biological or combined management action; (iii) direct outcome measures including change in coverage, abundance, biomass, survival, reoccurrence, biology (e.g. growth, height, leaf area) or pollen production. The wide range of quality of primary literature will be evaluated with a tailored system for assessing susceptibility to bias and the reliability of the studies. If extracted data are suitable for quantitative synthesis, we aim to calculate effect sizes and conduct meta-analyses

No saturation in the accumulation of alien species worldwide

Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.© The Author(s) 201