Worst Invasive Species Research Articles

The Effects of Laboratory Rearing Diet on Recruitment Behavior of Wasmannia Auropunctata (Hymenoptera: Formicidaea)

Wasmannia auropunctata (Roger) (Hymenoptera: Formicidae) is among the world's worst invasive species, and there is an increasing need for effective control methods for this species. Existing chemical treatments and baits used in managing other invasive ant species may not be as effective for managing W. auropunctata. Development of effective ant control treatments and baits depends on laboratory experiments to test the potential efficacy of a large number of products and control methods prior to implementation of large-scale field studies. However, anecdotal evidence suggests that laboratory-raised W. auropunctata may respond differently than their wild counterparts to bait types, and if this is the case, laboratory trials may not accurately predict results under field conditions. Here we report on experimental research investigating whether ant colonies raised in laboratories, and those in the field, show different patterns of recruitment to non-toxic baits. Laboratory and wild colony recruitment to non-toxic Hawaii Ant Lab gel bait, pureed tuna, and 50% gelled sucrose solution was measured via multi-choice and no-choice field recruitment studies. Secondly, we discuss experiments testing whether the bait preference of laboratory-raised W. auropuncata varies with their base diet. We tested 4 base diets: (1) lipid rich, (2) protein rich, (3) carbohydrate rich, and (4) a “complete” diet with lipid, protein, and carbohydrates offered as a buffet. Overall, we found that laboratory colonies differed from wild W. auropunctata in their foraging behaviors in no-choice and multi choice experiments, particularly in their levels of recruitment to the Hawaii Ant Lab gel bait. This contrast indicates that experimental trials may give misleading indications of potential outcomes of field trials. Further research is needed on optimal laboratory diets for laboratory-reared ant colonies. However, our results suggest that behavioral differences may be mitigated if colonies are maintained on a nutritionally limited diet while conducting laboratory experiments.

Ecology and Environmental Impact of Myriophyllum heterophyllum, an Aggressive Invader in European Waterways

The submerged evergreen aquatic plant Myriophyllum heterophyllum is among the worst invasive species in Europe, causing severe problems especially in navigation channels but also lentic systems. This review aims to provide a comprehensive overview and update on the current distribution and risks associated with this species in Europe and elsewhere. We provide an evaluation of current identification keys since misidentification can underestimate the extent of its spread. In addition, hybridization with other milfoil species has been reported in North America but seems unlikely in Europe. We further describe in detail the ecology, specifically resource requirements and biotic interactions with other plants, herbivores and pathogens as well as the spread potential of the species. Good knowledge of the autecology and synecology of this species should allow some conclusions about environmental factors possibly related to its invasive growth and is mandatory for the preparation of species-specific management measures. Finally, we outline the status of regulations coming into effect in member states of the European Union (EU) and provide an overview of applied and potential management practices.

The Influence of Processing and Particle Size on Binderless Particleboards Made from Arundo donax L. Rhizome.

The giant reed (Arundo donax L.) is considered one of the world’s 100 worst invasive species. The main method by which this species propagates is by growth of scattered fragments of rhizome, spreading without control with very strong, deep roots. Agricultural waste consists of lignocellulosic materials that can substitute natural wood and offer a suitable alternative with which to manufacture boards for furniture, packaging and building purposes. The objectives of this work were to obtain binderless particleboards using giant reed rhizome as the raw material, to evaluate their mechanical and physical properties according to the applicable European standards and to assess the self-binding mechanism of the particles in the board. Six types of boards (12 classes) were manufactured with giant reed rhizome biomass. They were manufactured with a temperature of 110 °C, a pressure of 2.5 MPa and pressing times of 7 and 15 min, applying one or two pressing cycles. The results achieved for modulus of rupture (14.2 N/mm2), modulus of elasticity (2052.45 N/mm2) and internal bonding strength (1.12 N/mm2) show that the mechanical properties were improved by using a smaller rhizome particle size and two pressing cycles.

Stronger regional biosecurity is essential to prevent hundreds of harmful biological invasions.

Biological invasions often transcend political boundaries, but the capacity of countries to prevent invasions varies. How this variation in biosecurity affects the invasion risks posed to the countries involved is unclear. We aimed to improve the understanding of how the biosecurity of a country influences that of its neighbours. We developed six scenarios that describe biological invasions in regions with contiguous countries. Using data from alien species databases, socio-economic and biodiversity data and species distribution models, we determined where 86 of 100 of the world's worst invasive species are likely to invade and have a negative impact in the future. Information on the capacity of countries to prevent invasions was used to determine whether such invasions could be avoided. For the selected species, we predicted 2,523 discrete invasions, most of which would have significant negative impacts and are unlikely to be prevented. Of these invasions, approximately a third were predicted to spread from the country in which the species first establishes to neighbouring countries where they would cause significant negative impacts. Most of these invasions are unlikely to be prevented as the country of first establishment has a low capacity to prevent invasions or has little incentive to do so as there will be no impact in that country. Regional biosecurity is therefore essential to prevent future harmful biological invasions. In consequence, we propose that the need for increased regional co-operation to combat biological invasions be incorporated in global biodiversity targets.

Integrating climate, water chemistry and propagule pressure indicators into aquatic species distribution models

Species distribution models are frequently used to anticipate the expansion of invasive species under the assumption that climate affects habitat conditions. Here, we investigated the influence of two additional factors that determine the spread, establishment, and impact of aquatic organisms: propagule pressure and water chemistry. Our case study species is the New Zealand Mud Snail (Potamopyrgus antipodarum, Tateidae, Mollusca), one of the 100 worst invasive species in Europe. We calibrated species distribution models combining three types of indicators (climate, water chemistry, and propagule pressure), and two scales (Iberian Peninsula vs. Ebro River catchment) using the Maxent algorithm. Propagule pressure improved the accuracy of models and enlarged the area susceptible to invasion by 16% at the Iberian Peninsula scale, and by 36% at the catchment scale. Among propagule pressure indicators, accessibility was the single most important indicator of the species distribution (33–35% contribution), illustrating the role of human-mediated dispersal for aquatic invaders. The catchment model integrating climate, propagule pressure and water chemistry indicators was the best option to prioritize river segments most vulnerable to colonization, characterized by high temperature, human influence and water pollution (nitrate concentration). High risk areas according to our models include the Mediterranean and North Atlantic coasts, central Spain, and the lowlands of the Ebro River catchment. Based on this study, we recommend including indicators of propagule pressure such as accessibility to reflect the opportunity to invade, and using water chemistry to further prioritize the river stretches most suitable to invasion. We conclude that distribution models integrating indicators at multiple scales are feasible, consistent in their predictions across scales, and show great potential to optimize management resources towards the prevention and early eradication of aquatic invasive species.

Mikania micrantha genome provides insights into the molecular mechanism of rapid growth

Mikania micrantha is one of the top 100 worst invasive species that can cause serious damage to natural ecosystems and substantial economic losses. Here, we present its 1.79 Gb chromosome-scale reference genome. Half of the genome is composed of long terminal repeat retrotransposons, 80% of which have been derived from a significant expansion in the past one million years. We identify a whole genome duplication event and recent segmental duplications, which may be responsible for its rapid environmental adaptation. Additionally, we show that M. micrantha achieves higher photosynthetic capacity by CO2 absorption at night to supplement the carbon fixation during the day, as well as enhanced stem photosynthesis efficiency. Furthermore, the metabolites of M. micrantha can increase the availability of nitrogen by enriching the microbes that participate in nitrogen cycling pathways. These findings collectively provide insights into the rapid growth and invasive adaptation.

Invasions of rainbow trout and brown trout in Japan: A comparison of invasiveness and impact on native species

AbstractMany species of salmonids have been stocked into waters outside of their native range. The invasiveness and impact of these species on native species varies depending on their biological traits, and on environmental conditions, such as climate. In Japan, rainbow trout and brown trout, both listed in 100 of the world's worst invasive alien species by the International Union for Conservation of Nature, occur as non‐native species. The invasiveness of these two species is thought to be related to seasonal flooding, given flood waters can physically damage fry and prevent population establishment. Rainbow trout have successfully invaded waters in Hokkaido, northern Japan, where the likelihood of flooding is low between June and July, when their fry emerge, but successful invasions are rare in regions south of Hokkaido. Brown trout, however, have successfully invaded waters not only in Hokkaido, but also other regions. Since brown trout have a similar life history to the native white‐spotted charr and masu salmon, with fry emerging before the flood season, they are more suited to the Japanese climate than Rainbow trout. Rainbow and brown trout interact with native species in various ways, but a common outcome of these interactions is the displacement of native charr species. Legal regulations of non‐native salmonids should be based on understandings of the ecological traits of each invasive species and regional impacts on native species. Given the ongoing nature of climate change, the nature and extent of the effects of rainbow and brown trout on native species might also change.

Potamopyrgus antipodarum (Gray, 1843) in Polish waters − its mitochondrial haplotype and role as intermediate host for trematodes

The New Zealand mud snail (Potamopyrgus antipodarum (Gray, 1843)) is on the list of one hundred worst invasive species. Researchers point out that genetic variation between populations of P. antipodarum manifested in differences in life-history traits. The main objective of our investigation was to gain pioneer knowledge about mitochondrial haplotypes of P. antipodarum in Polish waters on the background of these haplotypes recorded in the world and confirmation of the main role of P. antipodarum in the life cycle of digenean trematodes. We examined 1000 individuals of P. antipodarum from five water bodies in three different parts of Poland for the presence of larval stages of digenean trematodes. For several randomly selected individuals we carried out DNA sequencing of the 16S ribosomal RNA gene as marker of this non-indigenous mollusk. Only one 16S rRNA haplotype of P. antipodarum was recorded in Polish waters, defined in this study as haplotype 1 which turned out to be the most widespread in Europe. Potamopyrgus antipodarum is a source of trematode metacercariae belonging mainly to the family Echinostomatidae. As a result, we can demonstrate that it plays a role as the second intermediate host of digenean trematodes in European waters.

Short-Term Responses of Aquatic and Terrestrial Biodiversity to Riparian Restoration Measures Designed to Control the Invasive Arundo donax L.

Invasive species are among the top five causes of biodiversity loss worldwide. Arundo donax has progressively colonized the riparian zones of Mediterranean rivers with detrimental effects on terrestrial and aquatic biodiversity, being catalogued as one of the 100 worst invasive species. In order to control this invasive species and restore native riparian vegetation, different methods have been traditionally used, depending on the environmental, economic and social context. Here, the effect of repeated above-ground removal of A. donax on aquatic and terrestrial communities was assessed by testing two different frequencies of mowing (monthly-intensive and quarterly-extensive), combined with the plantation of native species. Specifically, it was evaluated if riparian vegetation, birds and aquatic macroinvertebrates showed significant responses throughout time and between restoration treatments based on 4-year annual biomonitoring data (2015–2018). Changes in taxonomic diversity and ecological quality indices for the different biological communities were tested using mixed-effect models (LMEs). Similarly, comparisons between restored and reference sites were also performed. LMEs were also applied to assess how riparian variables were related to bird and aquatic macroinvertebrate indices. NMDS and MGLM-Mvabund analyses were performed to detect significant post-treatment differences in taxa composition compared to the initial state and reference sites. During this short-term assessment, increases in riparian and aquatic macroinvertebrate richness and quality indices were found, as well as significant decreases in A. donax height, density and cover, without significant differences between restoration treatments. However, differential effects between extensive (positive-neutral effect) and intensive treatments (neutral-negative effect) were detected for bird richness, density and abundance. After three years of restoration actions, restored sites are still far from reference values in terms of taxa composition, species richness and ecological quality, especially for riparian vegetation and birds. Given the high cost and the great efforts required for restoration, extensive repeated mowing, together with native species plantation, are only recommended on river reaches not fully invaded by A. donax and with a high ecological interest.

Spatial structure of the microbiome in the gut of Pomacea canaliculata

BackgroundGut microbes can contribute to their hosts in food digestion, nutrient absorption, and inhibiting the growth of pathogens. However, only limited studies have focused on the gut microbiota of freshwater snails. Pomacea canaliculata is considered one of the worst invasive alien species in the world. Elucidating the diversity and composition of the microbiota in the gut of P. canaliculata snails may be helpful for better understanding the widespread invasion of this snail species. In this study, the buccal masses, stomachs, and intestines were isolated from seven P. canaliculata snails. The diversity and composition of the microbiota in the three gut sections were then investigated based on high-throughput Illumina sequencing targeting the V3-V4 regions of the 16S rRNA gene.ResultsThe diversity of the microbiota was highest in the intestine but lowest in the buccal mass. A total of 29 phyla and 111 genera of bacteria were identified in all of the samples. In general, Ochrobactrum, a genus of putative cellulose-degrading bacteria, was the most abundant (overall relative abundance: 13.6%), followed by Sediminibacterium (9.7%), Desulfovibrio (7.8%), an unclassified genus in the family Aeromonadaceae (5.4%), and Cloacibacterium (5.4%). The composition of the microbiota was diverse among the different gut sections. Ochrobactrum (relative abundance: 23.15% ± 7.92%) and Sediminibacterium (16.95 ± 5.70%) were most abundant in the stomach, an unclassified genus in the family Porphyromonadaceae (14.28 ± 7.29%) and Leptotrichia (8.70 ± 4.46%) were highest in the buccal mass, and two genera in the families Aeromonadaceae (7.55 ± 4.53%) and Mollicutes (13.47 ± 13.03%) were highest in the intestine.ConclusionsThe diversity and composition of the microbiome vary among different gut sections of P. canaliculata snails. Putative cellulose-degrading bacteria are enriched in the gut of P. canaliculata.

Red-eared Sliders Trachemys scripta elegans in southern Sydney, including new incursions

The invasive Red-eared Slider Trachemys scripta elegans has spread extensively, forming naturalised populations on all continents except Antarctica. Ranked among the 100 worst invasive species, there are biosecurity concerns that native turtles become outcompeted and displaced, as well as other speculative impacts. The actual ecological impacts in Australia have not been properly studied, however impacts shown in other countries are concerning. Incursions have presented in New South Wales, Queensland, Victoria, Western Australia and the Australian Capital Territory. A number of sightings have been reported from southern Sydney, including six sites where more than one slider has persisted. The incursions at Yeramba Lagoon in the Georges River National Park and the Centennial Parklands have been the most documented, whereas incursions in the Lime Kiln Bay Wetland, Rockdale Wetlands Corridor and Audley in the Royal National Park appear to have occurred recently. To date, breeding in southern Sydney has only been confirmed at Yeramba Lagoon. A range of removal techniques have been successfully applied to eradicate isolated incursions in Brisbane and Melbourne. However, these options are difficult to implement in southern Sydney sites where incursions occur in high visitation public lands.

Patterns of spatial genetic structures in Aedes albopictus (Diptera: Culicidae) populations in China

BackgroundThe Asian tiger mosquito, Aedes albopictus, is one of the 100 worst invasive species in the world and the vector for several arboviruses including dengue, Zika and chikungunya viruses. Understanding the population spatial genetic structure, migration, and gene flow of vector species is critical to effectively preventing and controlling vector-borne diseases. Little is known about the population structure and genetic differentiation of native Ae. albopictus in China. The aim of this study was to examine the patterns of the spatial genetic structures of native Ae. albopictus populations, and their relationship to dengue incidence, on a large geographical scale.MethodsDuring 2016–2018, adult female Ae. albopictus mosquitoes were collected by human landing catch (HLC) or human-bait sweep-net collections in 34 localities across China. Thirteen microsatellite markers were used to examine the patterns of genetic diversity, population structure, and gene flow among native Ae. albopictus populations. The correlation between population genetic indices and dengue incidence was also examined.ResultsA total of 153 distinct alleles were identified at the 13 microsatellite loci in the tested populations. All loci were polymorphic, with the number of distinct alleles ranging from eight to sixteen. Genetic parameters such as PIC, heterozygosity, allelic richness and fixation index (FST) revealed highly polymorphic markers, high genetic diversity, and low population genetic differentiation. In addition, Bayesian analysis of population structure showed two distinct genetic groups in southern-western and eastern-central-northern China. The Mantel test indicated a positive correlation between genetic distance and geographical distance (R2 = 0.245, P = 0.01). STRUCTURE analysis, PCoA and GLS interpolation analysis indicated that Ae. albopictus populations in China were regionally clustered. Gene flow and relatedness estimates were generally high between populations. We observed no correlation between population genetic indices of microsatellite loci in Ae. albopictus populations and dengue incidence.ConclusionStrong gene flow probably assisted by human activities inhibited population differentiation and promoted genetic diversity among populations of Ae. albopictus. This may represent a potential risk of rapid spread of mosquito-borne diseases. The spatial genetic structure, coupled with the association between genetic indices and dengue incidence, may have important implications for understanding the epidemiology, prevention, and control of vector-borne diseases.

Invasive Aquatic Plant Species of Chenderoh Reservoir, Malaysia and Jatiluhur Reservoir, Indonesia

The sampling was carried out in two sampling sites; Chenderoh Reservoir, Malaysia and Jatiluhur Reservoir, Indonesia. These reservoirs are the initial of cascade reservoirs on Perak River and Citarum River. The aquatic plants distribution and abundance were recorded, and water quality parameters were measured. A total of 23 aquatic plant species from 14 families were identified. The populations of water hyacinth (Eichhornia crassipes) and giant salvinia (Salvinia molesta) were recorded in all sampling points of both reservoirs. Based on the TSI (Chl a), Chenderoh Reservoir was subjected to a mesotrophic, whereas, Jatiluhur Reservoir was subjected to an eutrophic reservoir. E. crassipes and S. molesta which were abundant in those reservoirs were listed in the 100 world worst invasive alien species.

Factors affecting space use by wild boars (Sus scrofa) in high-elevation tropical forests

The wild boar (Sus scrofa Linnaeus, 1758) is considered one of the 100 worst invasive species in the world and is present in the high-elevation forests in Brazil. Our objective was to understand how landscape and atmospheric conditions affect space use by wild boars. We hypothesized that wild boars would be more frequent at lower elevations, warmer and wetter forested areas, and away from human disturbances. After three years of data collection (2013–2016) using 16 camera traps, 881 independent records were obtained with a mean of 4.44 ± 9.25 pigs per record. Wild boar frequency of occurrence was higher at lower elevations, in more humid and warmer areas, and farther away human disturbance factors, corroborating our initial hypothesis. Understanding space-use patterns of wild boars is necessary for the design of management strategies that target areas of more intense usage, as well as for defining more effective population-control techniques.

Non-destructive method for detecting Aphanomyces astaci, the causative agent of crayfish plague, on the individual level

The pathogenic oomycete Aphanomyces astaci, transmitted mainly by invasive North American crayfish, causes the crayfish plague, a disease mostly lethal for native European crayfish. Due to its decimating effects on native crayfish populations in the last century, A. astaci has been listed among the 100 worst invasive species. Importantly, detecting the pathogen in endangered native crayfish populations before a disease outbreak would provide a starting point in the development of effective control measures. However, current A. astaci-detection protocols either rely on degradation-prone eDNA isolated from large volumes of water or, if focused on individual animals, include killing the crayfish. We developed a non-destructive method that detects A. astaci DNA in the microbial biofilm associated with the cuticle of individual crayfish, without the need for destructive sampling. Efficiency of the new method was confirmed by PCR and qPCR and the obtained results were congruent with the traditional destructive sampling method. Additionally, we demonstrated the applicability of the method for A. astaci monitoring in natural populations. We propose that the new method should be used in future monitoring of A. astaci presence in endangered European native crayfish individuals as an alternative to eDNA-based monitoring.

Identification of Key Genes for the Precise Classification between Solenopsis invicta and S. geminata Facilitating the Quarantine Process.

One of the 100 worst invasive exotic species, Solenopsis invicta (red imported fire ant), has the possibility to induce an allergic reaction that may eventually cause death from its aggressive stinging. In 2017, S. invicta was found at a container yard in Gamman Port, Busan, South Korea for the first time. It may result in an infestation of fire ants in the Korean environment. After this incident, sensitive quarantine procedures are required to detect possible contamination of fire ants in imported containers. However, currently, fire ant identification relies on phenotypic characteristics. This requires highly trained experts for identification and there are not enough to cover all imported containers. Here, we develop a key molecular marker to distinguish S. invicta from others using the whole genome sequence (WGS) of collected S. invicta from Gamman Port and NCBI-deposited WGS data of S.invicta and S. geminata. The consolidated genotypes of Solenopsis genus successfully indicate the distinguishable gene. The gel-based experimental validation confirmed expected classification and the developed cleaved amplified polymorphic sequences (CAPS) marker also gave a consistent result. Using the CAPS marker derived from our consolidated genotypes, the samples collected from containers in several ports can be easily tested by PCR in a few hours. The quick and easy test would increase not only the labor efficiency but also the environmental safety from fire ants.

A stochastic individual-based model for the growth of a stand of Japanese knotweed including mowing as a management technique

Invasive alien species are a growing threat for the environment and health. They also have a major economic impact, as they can damage many infrastructures. The Japanese knotweed (Fallopia japonica), present in North America, Northern and Central Europe as well as in Australia and New Zealand, is listed by the World Conservation Union as one of the world's worst invasive species. So far, most models have dealt with the knotweed invasion without management. This paper aims to provide a model able to study and predict the dynamics of a stand of Japanese knotweed taking into account mowing as a management technique. The model is stochastic and individual-based, which allows us to take into account the behaviour of individuals depending on their size and location, as well as individual stochasticity. We set plant dynamics parameters based on a calibration with field data and studied the influence of the initial population size, the mean number of mowing events a year and the management project duration on the mean area and mean number of crowns. The results provide the sets of parameters for which it is possible to obtain stand eradication, and the minimum duration of the management project necessary to achieve this.

Phylogeographic patterns and demographic history of Pomacea canaliculata and Pomacea maculata from different countries (Ampullariidae, Gastropoda, Mollusca)

Invasive species of Pomacea snails are of growing concern when it comes to the conservation of global biodiversity. Pomacea canaliculata has been listed among the world’s 100 worst invasive species. In this work, phylogeographic patterns and the demographic history of P. canaliculata and P. maculata from different countries were analyzed using mtDNA cytochrome c oxidase subunit-I (COI) sequences. The results showed that P. canaliculata and P. maculata had high genetic diversity, significant genetic differentiation, limited gene flow and stable population dynamics among different countries. Genetic diversity of P. canaliculata was higher than P. maculata. Our study will also provide important information for the effective prevention and control of the spread of Pomacea snails.

The South America Tomato Leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), Spreads Its Wings in Eastern Africa: Distribution and Socioeconomic Impacts.

Following the arrival of Tuta absoluta Meyrick in the eastern African subregion in 2012, several studies have shown numerous ecological aspects of its invasion. We investigated the impact of T. absoluta on people's livelihoods across four counties of Kenya. Here, 200 farmers in the country were interviewed in person using semistructured questionnaires. In addition to livelihood surveys, T. absoluta distribution was mapped between 2016 and 2018 to determine its current distribution across four countries (Kenya, Sudan, Tanzania, and Uganda) in the subregion. Albeit a recent invader, T. absoluta is abundant and distributed throughout the subregion and is viewed as the worst invasive alien species of agriculturally sustainable livelihoods by tomato farmers. The arrival of T. absoluta in the subregion has resulted in livelihood losses and increased both the cost of tomato production and frequency of pesticide application. We recommend the implementation of biological control along, with other control measures in an integrated approach, against T. absoluta in the subregion, where its impact on sustainable livelihoods is serious and long-term control strategies are required to curb its detrimental effects.

La influencia humana, clave para entender la biogeografía de especies invasoras en el Antropoceno

Las invasiones biológicas han revolucionado el concepto de biogeografía en el Antropoceno, ya que su distribución geográfica ya no depende de su capacidad intrínseca de movimiento y las barreras biogeográficas clásicas, sino que depende directamente de actividades humanas que favorecen, intencionada o accidentalmente, su expansión. Por tanto, las técnicas de modelización geográfica han de tener en cuenta las particularidades de las especies invasoras para poder anticipar su distribución potencial en el futuro. En este estudio, utilizamos un listado de 57 de las peores especies invasoras en Europa (18 plantas, 15 vertebrados, 12 invertebrados y 12 organismos acuáticos) para comparar la influencia climática y humana en la distribución a gran escala de especies invasoras. Identificamos un total de nueve grandes vectores de introducción, entre los que destacan el transporte, el cultivo ornamental y el comercio. Localizamos siete variables relacionadas con estos vectores de introducción que utilizamos junto con variables climáticas como predictores en Modelos Ecológicos de Nicho (MEN): accesibilidad, densidad de población, PIB, grado de antropización, cobertura de uso agrícola y urbano, distancia a carreteras y puertos comerciales. La temperatura mínima anual es el predictor más importante en los modelos, seguida de la distancia a puertos, el PIB y la accesibilidad. Sorprendentemente, los modelos que incluyen variables humanas no son estadísticamente mejores que los basados en variables climáticas únicamente, si bien predicen un aumento medio del 8% en la superficie europea susceptible a la invasión. Tal incremento se produce fundamentalmente en zonas muy antropizadas donde la posibilidad de invasión es obviamente mayor. En el caso de la Península Ibérica, esto se traduce en un aumento del riesgo de invasión en la zona de levante, valle del Ebro y alrededores de grandes ciudades. Concluimos por tanto que el clima es importante, pero no suficiente para anticipar efectivamente la expansión de especies invasoras, y por tanto, cualquier información disponible que esté directamente relacionada con los vectores de introducción ha de ser incorporada de forma rutinaria en los MEN para optimizar los recursos dedicados a la prevención, respuesta rápida y control a largo plazo de especies invasoras.