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Species invading non‐native habitats can cause irreversible environmental damage and economic harm. Yet, how introduced species become widespread invaders remains poorly understood. Adaptation within native‐range habitats and rapid adaptation to new environments may both influence invasion success. Here, we examine these hypotheses using 7058 SNPs from 36 native, 40 introduced and 19 farmed populations of tench, a fish native to Eurasia. We examined genetic structure among these populations and accounted for long‐term evolutionary history within the native range to assess whether introduced populations exhibited lower genetic diversity than native populations. Subsequent to infer genotype–environment correlations within native‐range habitats, we assessed whether adaptation to native environments may have shaped the success of some introduced populations. At the broad scale, two glacial refugia contributed to the ancestry and genomic diversity of tench. However, native, introduced and farmed populations of admixed origin exhibited up to 10‐fold more genetic diversity (i.e., observed heterozygosity, expected heterozygosity and allelic richness) compared to populations with predominantly single‐source ancestry. The effects of introduction to a new location were also apparent as introduced populations exhibited fewer private alleles (mean = 9.9 and 18.9 private alleles in introduced and native populations, respectively) and higher population‐specific Fst compared to native populations, highlighting their distinctiveness relative to the pool of allelic frequencies across tench populations. Finally, introduced populations with varying levels of genetic variation and similar genetic compositions have become established and persisted under strikingly different climatic and ecological conditions. Our results suggest that lack of prior adaptation and low genetic variation may not consistently hinder the success of introduced populations for species with a demonstrated ability to expand their native range.

Our ability to predict the spread of alien species is largely based on knowledge of previous invasion dynamics of individual species. However, in view of the large and growing number of alien species, understanding universal spread patterns common among taxa but specific to regions would considerably improve our ability to predict future dynamics of biological invasions. Here, using a comprehensive dataset of years of first record of alien species for four major biological groups (birds, nonmarine fishes, insects, and vascular plants), we applied a network approach to uncover frequent sequential patterns of first recordings of alien species across countries worldwide. Our analysis identified a few countries as consistent early recorders of alien species, with many subsequent records reported from countries in close geographic vicinity. These findings indicate that the spread network of alien species consists of two levels, a backbone of main dispersal hubs, driving intercontinental species movement, and subsequent intracontinental radiative spread in their vicinity. Geographical proximity and climatic similarity were significant predictors of same-species recording among countries. International trade was a significant predictor of the relative timing of species recordings, with countries having higher levels of trade flows consistently recording the species earlier. Targeting the countries that have emerged as hubs for the early spread of alien species may have substantial cascading effects on the global spread network of alien species, significantly reducing biological invasions. Furthermore, using these countries as early-warning system of upcoming invasions may also boost national prevention and invasion preparedness efforts.

Ecological invasions, where non-native species spread to new areas, grow to high densities and have large, negative impacts on ecological communities, are a major worldwide problem. Recent studies suggest that one of the key mechanisms influencing invasion dynamics is personality-dependent dispersal: the tendency for dispersers to have a different personality type than the average from a source population. We examined this possibility in the invasive mosquitofish (Gambusia affinis). We measured individual tendencies to disperse in experimental streams and several personality traits: sociability, boldness, activity and exploration tendency before and three weeks after dispersal. We found that mosquitofish display consistent behavioural tendencies over time, and significant positive correlations between all personality traits. Most notably, sociability was an important indicator of dispersal distance, with more asocial individuals dispersing further, suggesting personality-biased dispersal on an invasion front. These results could have important ecological implications, as invasion by a biased subset of individuals is likely to have different ecological impacts than invasion by a random group of colonists.

Invasion rates have increased in the past 100 y irrespective of international conventions. What characterizes a successful invasion event? And how does genetic diversity translate into invasion success? Employing a whole-genome perspective using one of the most successful marine invasive species world-wide as a model, we resolve temporal invasion dynamics during independent invasion events in Eurasia. We reveal complex regionally independent invasion histories including cases of recurrent translocations, time-limited translocations, and stepping-stone range expansions with severe bottlenecks within the same species. Irrespective of these different invasion dynamics, which lead to contrasting patterns of genetic diversity, all nonindigenous populations are similarly successful. This illustrates that genetic diversity, per se, is not necessarily the driving force behind invasion success. Other factors such as propagule pressure and repeated introductions are an important contribution to facilitate successful invasions. This calls into question the dominant paradigm of the genetic paradox of invasions, i.e., the successful establishment of nonindigenous populations with low levels of genetic diversity.

1. This paper examines the circumstances under which control programmes may reduce the range of two widespread invasive weeds of riparian habitats: Impatients glandulifera (Himalayan balsam) and Heracleum mantegazzianum (giant hogweed). 2. The spread of both species was modelled using MIGRATE, a spatially explicit model that incorporates realistic demographic parameters and multiple dispersal mechanisms. Simulations of a range of control scenarios were run within a geographical information system (GIS) using authentic landscapes based on topographic, hydrological and land cover maps of County Durham, UK. Results were interpreted at both a catchment and a regional scale. 3. Six representative strategies were explored that prioritized control as follows: at random, in relation to human population density, or by the size, age (new and old) or spatial distribution of weed populations. These strategies were assessed at different intensities of management (area treated per year) and for varying efficiencies (proportion of plants destroyed) as well as the timeliness (how long since the species became established) of implementations. 4. Strategies that prioritized control based on weed population and spatial characteristics were most effective, with plant population size and spatial distribution being the key parameters. The reduction in geographical range within a catchment or region following control was always greater for H. mantegazzianum than I. glandulifera due to its slower rate of spread. 5. Successful control of both species at a regional scale is only possible for strategies based on species distribution data, undertaken at relatively high intensities and efficiencies. The importance of understanding the spatial structure of the population and potential habitat available, as well as being able to monitor the progress of the eradication programme, is highlighted. Tentative conclusions are offered as to the feasibility of eradicating these species at a regional scale.

There has been considerable recent interest in modelling the potential distributions of invasive species. However, research has developed in two opposite directions: the first, focusing on screening, utilizes phenomenological models; the second, focusing on predictions of invasion dynamics, utilizes mechanistic models. Here, we present hybrid modelling as an approach to bridge the gap and to integrate the advantages of both research directions. Global. First, we briefly summarize the characteristics and limitations of both approaches (screening vs. understanding). Then, we review the recent developments of hybrid models, discuss their current problems and offer suggestions to improve them. Generally, hybrid models are able to combine the advantages of currently used phenomenological and mechanistic approaches. Main challenges in building hybrid models are the choices of the appropriate degree of detail and efficiency and the decision on how to connect the different sub-models. Given these challenges, we discuss the links between the phenomenological and the mechanistic model parameters, the underlying concepts of fundamental and realized niches and the problem of feedback loops between population dynamics and environmental factors. Once the above challenges have been addressed and the necessary framework has been developed, hybrid models will provide outstanding tools for overcoming past limitations and will provide the means to make reliable and robust predictions of the potential distribution of invasive species, their population dynamics and the potential outcomes of the overall invasion process.

Given the high costs associated with fruit fly (Tephritidae) invasions, there is a need to better understand and predict the risks of future invasions. We assembled a global database of historical Tephritidae invasions with the objective to identify biological and socioeconomic drivers that explain invasions. We investigate the tendencies of certain species to invade and the characteristics of regions that make them more prone to invasions. Our database documented the occurrence (presence/absence) and status (native/non-native) of individual Tephritidae species in each country in the world. Values of several socioeconomic and environmental variables were also assembled and considered as explanatory variables. A generalized linear mixed-effects model framework was used to evaluate the utility of these variables for predicting the country-level occurrence of each species outside of its native range. A total of 44 species were identified as having been accidentally introduced. Most species of invading Tephritidae have established in five or fewer countries. The number of invasions has rapidly increased since the 1950s. Climatic similarity between native and invaded countries and gross domestic product of the invaded country significantly increased the incidence of invasion, whereas distance to the native range had a negative effect on the probability that a given country would be invaded. Our analysis revealed that both economic and biological factors explain patterns of historical Tephritid invasions. Despite the rising efforts to prevent new invasions, additional species may continue to invade, and many currently established species will likely continue to expand their ranges into new areas.

Japanese beetle ( Popillia japonica) is an invasive agricultural pest throughout the eastern United States and its distribution is expanding westward. Understanding how climate and land use intensification interact to affect Japanese beetle population dynamics and spread is essential to predict which areas are vulnerable to increased pest pressure. In this study, we combine data from the Global Biodiversity Information Facility (GBIF) with data from local state agricultural agencies and University extension offices to model how land cover and climate affect Japanese beetle occurrences at the leading edge of an invasion front in the central United States over 5 years. We found that beetle occurrences were positively correlated with proportion of developed areas, proportion of corn and soybean, minimum temperature, and precipitation within counties, and negatively correlated with the proportion of grassland and pasture, and maximum temperature. We modeled Japanese beetle occurrences in the near future and for future climate scenarios and found high probability of occurrence for Japanese beetles across the entire region. Our study highlights the importance of supplementing community science data in rural areas and including a time variable when assessing habitat associations for invasive species in novel areas.

The Atlantic blue crab Callinectes sapidus, which is native to the western Atlantic coast and listed among the 100 most invasive alien species in the Mediterranean Sea, is attracting a great deal of interest because of its rapid colonisation of new areas, the significant increase in its population, and the impacts it may have on ecosystems and ecosystem services. Outside its natural distribution range, the species was first found on European Atlantic coasts in the early 1900s and was introduced into the Mediterranean Sea a few decades later, probably through ballast water. Currently, it is found in almost the entire Mediterranean Basin and is also expanding into the Black Sea and along the north African and Iberian Atlantic coasts. Based on a systematic review of C. sapidus occurrences, this study describes its distribution, aggregation patterns, and spatial structure in Northwest Europe, the Mediterranean Sea, and adjacent waters through a series of ecological indicators elaborated using GIS spatial–temporal statistics. The main results highlight that the species is expanding in the Mediterranean and adjacent waters, while in northern Europe, the population remains confined in some areas. Furthermore, the main species detection methods are analysed, finding that traps and nets are the most frequently used methods, and management suggestions are provided.

Background: In recent years, the impact of climate change on human health has attracted considerable attention; the effects on malaria have been of particular interest because of its disease burden and its transmission sensitivity to environmental conditions. Objectives: We investigated and illustrated the role that dynamic process-based mathematical models can play in providing strategic insights into the effects of climate change on malaria transmission. Methods: We evaluated a relatively simple model that permitted valuable and novel insights into the simultaneous effects of rainfall and temperature on mosquito population dynamics, malaria invasion, persistence and local seasonal extinction, and the impact of seasonality on transmission. We illustrated how large-scale climate simulations and infectious disease systems may be modeled and analyzed and how these methods may be applied to predicting changes in the basic reproduction number of malaria across Tanzania. Results: We found extinction to be more strongly dependent on rainfall than on temperature and identified a temperature window of around 32–33°C where endemic transmission and the rate of spread in disease-free regions is optimized. This window was the same for Plasmodium falciparum and P. vivax, but mosquito density played a stronger role in driving the rate of malaria spread than did the Plasmodium species. The results improved our understanding of how temperature shifts affect the global distribution of at-risk regions, as well as how rapidly malaria outbreaks take off within vulnerable populations. Conclusions: Disease emergence, extinction, and transmission all depend strongly on climate. Mathematical models offer powerful tools for understanding geographic shifts in incidence as climate changes. Nonlinear dependences of transmission on climate necessitates consideration of both changing climate trends and variability across time scales of interest.