Non-native Aquatic Species Research Articles

Tracking aquatic non-native macroinvertebrate species in Germany using long-term data

Biological invasions pose a global challenge, threatening both biodiversity and human well-being. Projections suggest that as invasions increase, the financial costs associated with management and the ecological harm they cause will also escalate. Here, we examined whether long-term biomonitoring strategies were adequate to identify and track benthic aquatic non-native macroinvertebrate species by using the German subset (151 time series; 129 of which reported non-native species) of the currently most comprehensive European long-term dataset of 1816 macroinvertebrate community time series from 22 European countries. The detection of aquatic non-native species was directly linked to the availability of long-term sites and thus, monitoring effort, having identified the spatio-temporal occurrence of 32 non-native species. The available long-term monitoring site data were mostly concentrated in the western part of Germany, predominantly covering the Rhine River and its tributaries. The spatially biased network of long-term monitoring sites, therefore, naturally skews the detection and reporting of aquatic non-native species toward this area and underestimates Eastern and Southern regions, impeding the comprehension of invasion dynamics. However, based on the available data, we found that the absolute number of non-native species increased and the proportion of non-native species relative to native species decreased over time. This indicates complex ecological interactions between native and non-native species and underlines the value of long-term data for investigating invasion dynamics. Considering the value of comprehensive monitoring networks, a spatially biased network delays the application of management and mitigation plans, possibly worsening the ecological and economic effects of biological invasions in Germany. The results provided here indicate the disadvantages of biased datasets, but simultaneously underline the enormous potential of a dense network of long-term monitoring. Our results also highlight the urgent need to increase and diversify long-term biomonitoring efforts throughout Germany to cover the main freshwater resources and their connections where the introduction risk of non-native species is the highest. Centrally collating such data would provide a profound basis for the monitoring of spreading aquatic non-native species and could serve the implementation of national biosecurity efforts.

The effects of commercial 2,4-D herbicide on game fish species: Natural lake water vs. laboratory system water

Aquatic herbicides with active ingredient 2,4-dichlorophenoxyacteic acid (2,4-D) are commonly used to control and combat aquatic non-native species that cause detrimental impacts including habitat destruction, strained resources among biota, and biodiversity loss. While many (eco)toxicology studies are performed in the laboratory under highly controlled circumstances, these studies may disregard the nuances and disorder that come with the complexity of natural aquatic ecosystems. Therefore, we conducted a series of laboratory experiments using laboratory system water, different lake waters, and different water parameters to determine the effects of ecologically relevant concentrations of 2,4-D (0.00–4.00 ppm a.e.) on the development and survival of two freshwater game species (Sander vitreus and Esox lucius). For 2,4-D exposures using different water sources, there were significant main effects of 2,4-D concentration and water source on walleye embryo and larval survival, however, there was no significant interaction between 2,4-D exposure and water source. For 2,4-D exposures and pH (5–9 pH), there were significant main effects of 2,4-D concentration and pH on walleye and northern pike embryo survival and a significant interaction between 2,4-D exposure and pH. Our results indicate that 2,4-D exposures in controlled laboratory system water can predict similar outcomes as 2,4-D exposures in natural lake water. Moreover, individual water parameters, such as pH, play a significant role in the toxicity of 2,4-D. Taken together, these results suggest that highly controlled laboratory studies are a useful tool for predicting impacts on survival of non-target fish in natural waters, but it is crucial for management agencies to consider individual water sources and specific lake water parameters in herbicide risk assessments to minimize the impacts to non-target organism.

Biological testing of ships’ ballast water indicates challenges for the implementation of the Ballast Water Management Convention

Ships’ ballast water and sediments are vectors that contribute to the unintentional spread of aquatic non-native species globally. Ballast water management, as well as commissioning testing of ballast water management systems and compliance monitoring under the regulations of the International Maritime Organization (IMO) aim at minimizing the unwanted spread of organisms. This study compiles data for treated ballast water samples collected and analyzed from 228 ships during 2017–2023. The samples were collected from the ballast discharge line or directly from the ballast tank for enumeration of living organism concentrations in the categories of ≥50µm and <50 to ≥10µm -sized organisms, as well as indicator microbes in comparison to the ballast water performance standard of the IMO (Regulation D-2). In addition, several ship-specific factors were examined to infer potential factors affecting compliance rates. Nearly all ships were compliant with the ballast water performance standard for indicator microbes and <50 to ≥10µm -sized organisms, whereas almost half of all samples exceeded the limit of ten viable organisms m-3 for the ≥50µm -sized organisms. Compliance testing results did not differ significantly between sampling years, indicating that compliance rate did not change through time. The rate of compliance was higher for commissioning testing than compliance testing. Clear ship- or system-specific factors that lead to compliance or non-compliance were not detected, even though type of ballast water management system, filter mesh size associated with the system and source of ballast water affected compliance significantly either for the samples taken from the discharge line, or ballast tank. As compliance did not improve significantly over time, compliance testing of ships’ ballast water should be undertaken to ensure that the systems remain operational after commissioning and ships meet requirements of the D-2 standard. Furthermore, the study outcomes promote further research on the efficiency of filter mesh sizes and different filtration units associated with ballast water management systems, to improve mechanical removal of larger organisms. Finally, as several ships exceeded the compliance limit by hundreds or thousands of living organisms, technological advancements and operational measures may be needed to improve the overall reliability of ballast water management.

Risk Screening of Invasive Aquatic Species and a Survey of Fish Diversity Using Environmental DNA Metabarcoding Analysis in Shanghai

As the largest coastal city in China, Shanghai’s rapid development in transportation, tourism, trade, and commerce has facilitated the spread and invasion of non-native aquatic organisms. Aquatic organisms are highly elusive, and once established, eradicating them becomes a challenging task. Currently, our understanding of the invasion risk posed by non-native aquatic species in Shanghai is limited. Therefore, it is imperative to investigate the pathways of introduction, distribution, and dispersion and the invasion risk and impacts of non-native aquatic organisms in Shanghai. This study investigated aquatic organisms in Shanghai’s primary water bodies, including Huangpu River, Suzhou River, and Dianshan Lake. The risk assessment was conducted using the Aquatic Species Invasiveness Screening Kit (AS-ISK), and field monitoring was performed with environmental DNA (eDNA) technology. Results of the risk assessment indicate that among the 21 evaluated species, 9 fall into the medium-to-high-risk category with scores ≥26, while 12 are classified as low-risk with scores <26. The top four species with the highest invasion risk are Gambusia affinis, Pomacea canaliculata, Lepomis macrochirus, and Coptodon zillii. This study identified 54 fish species belonging to seven orders, 16 families, and 42 genera at 16 sampling sites in Shanghai, among which Channa maculata, Micropterus salmoides, and Misgurnus bipartitus are non-native. The results suggest that Shanghai faces a high invasion risk of aquatic species, necessitating enhanced scientific prevention and control measures. Early monitoring is essential for species with medium-to-high invasion risk, and a further evaluation and analysis of the risks associated with introduced fish species already present in Shanghai are recommended for aquaculture practices.

Preserving Uruguay’s freshwater systems: the need to restrict invasive species introductions for sustainable production

This manuscript critically examines the history of non-native aquatic species introductions in Uruguay, emphasizing the role of public institutions. Despite global concerns about biodiversity threats from these introductions, Uruguay’s reliance on animal production and aquaculture involving non-native species has grown since the 1980s. State institutions, despite past failures, have promoted these introductions without comprehensive risk assessments. Notable cases, including failed attempts with species like the herbivorous carp, American bullfrog, Nile tilapia, Australian redclaw crayfish, and American mink, raise concerns about invasive populations due to a lack of proper risk assessments and prevention measures. Previous examples were deficient in escape monitoring, oversight of specimens after farm closures, and considerations for the presence of new pathogens. This highlights the need for more informed and responsible approaches to prevent invasive species’ establishment, advocating for rigorous analysis and risk assessments before any introduction. We propose overcoming historically fragmented decision-making processes by establishing a bridging structure that coordinates inter- and intra-institutional efforts, engages with the academic sector and social organizations, and evaluates the introductions. This platform can prioritize protecting aquatic ecosystems, fostering sustainable growth, and maintaining ecological balance, contributing to the solution of the problem by facilitating coordinated efforts and engaging diverse stakeholders.

Diversity and distribution of Aphanomyces astaci in a European hotspot of ornamental crayfish introductions

Ornamental trade has become an important introduction pathway of non-native aquatic species worldwide. Correspondingly, there has been an alarming increase in the number of established crayfish of aquarium origin in Europe over the previous decade. The oomycete Aphanomyces astaci, the pathogen causing crayfish plague responsible for serious declines of European crayfish populations, is dispersed with introduced North American crayfish. The role of ornamental taxa in introducing and spreading different genotypes of this pathogen in open waters remains unclear. We investigated the distribution, prevalence, and diversity of A. astaci in Budapest, Hungary, which became a hotspot of aquarium crayfish introductions. Their establishment in this area was facilitated by locally abundant thermal waters. We screened for A. astaci in six host taxa from 18 sites sampled between 2018 and 2021: five cambarids (Cambarellus patzcuarensis, Faxonius limosus, Procambarus alleni, P. clarkii, P. virginalis) and one native astacid (Pontastacus leptodactylus). The pathogen was confirmed at five sampled sites in four host taxa: P. virginalis, P. clarkii, F. limosus, and for the first time in European open waters also in P. alleni. Genotyping was successful only in individuals from two different brooks where multiple host species coexisted but revealed unexpected patterns. Mitochondrial B-haplogroup of A. astaci, previously usually reported from Pacifastacus leniusculus or infected European species, was detected in P. virginalis at both sites, and in both F. limosus and P. virginalis sampled from a thermally stable tributary of Barát brook in 2018. In contrast, A-haplogroup of A. astaci was detected in coexisting F. limosus, P. virginalis and P. clarkii sampled in the same watercourse just a few hundred meters downstream in 2020. Additional genotyping methods indicated that a previously unknown A. astaci strain was associated with the latter haplogroup. One P. virginalis individual from 2020 was apparently co-infected by strains representing both mitochondrial haplogroups. The results indicated multiple sources of A. astaci in Budapest, likely directly associated with the introduction of ornamental species, interspecific transmission of this pathogen among ornamental hosts, and potential for a quick spatial or temporal turnover of dominant A. astaci strains at a certain locality. This highlights that in regions with high richness of potential A. astaci hosts, host taxon/pathogen genotype combinations become unpredictable, which might prevent reliable genotyping of pathogen sources in local crayfish mass mortalities.

Identifying and Managing Areas under Threat in the Iberian Peninsula: An Invasion Risk Atlas for Non-Native Aquatic Plant Species as a Potential Tool.

Predicting the likelihood that non-native species will be introduced into new areas remains one of conservation's greatest challenges and, consequently, it is necessary to adopt adequate management measures to mitigate the effects of future biological invasions. At present, not much information is available on the areas in which non-native aquatic plant species could establish themselves in the Iberian Peninsula. Species distribution models were used to predict the potential invasion risk of (1) non-native aquatic plant species already established in the peninsula (32 species) and (2) those with the potential to invade the peninsula (40 species). The results revealed that the Iberian Peninsula contains a number of areas capable of hosting non-native aquatic plant species. Areas under anthropogenic pressure are at the greatest risk of invasion, and the variable most related to invasion risk is temperature. The results of this work were used to create the Invasion Risk Atlas for Alien Aquatic Plants in the Iberian Peninsula, a novel online resource that provides information about the potential distribution of non-native aquatic plant species. The atlas and this article are intended to serve as reference tools for the development of public policies, management regimes, and control strategies aimed at the prevention, mitigation, and eradication of non-native aquatic plant species.

The influence of non-native invertebrate species in the food web structure of two Neotropical reservoirs

To investigate the influence of non-native aquatic invertebrate species on food web structure, we selected two reservoirs located in the Grande River (upper Paraná River basin, Brazil) with similar fish communities, different age and different taxa introductions history. We quarterly collected fish and benthonic macroinvertebrates samples in the Volta Grande and Funil reservoirs between October 2015 and August 2016. We used conventional methods of diet evaluation to assess the sampled fish and measured the availability of invertebrates (i.e. composition and density) present in the sediment samples from each reservoir. In addition, we performed a structural analysis of trophic interaction networks. Based on the data obtained, it was possible to identify that in Volta Grande most of the energy flow, between benthonic invertebrates (prey) and the fish community (predators), occurred through non-native prey species, especially Limnoperna fortunei and Macrobrachium amazonicum, while in Funil it was shared between non-native and native prey. Species loss simulations indicated that the networks did not differ substantially between random losses and losses between groups. In general, there was a decrease in the probability of occurrence of highly connected species in both reservoirs and between non-native and native species. Results showed that the new interactions among species influenced the importance of the available energy sources for the fish in the Volta Grande reservoir. The presence of non-native prey, especially M. amazonicum, may influence the interaction network structure, promoting community dependence on non-native species to ensure robustness to environmental disturbances. In the absence of pre-invasion data, the comparative study between systems with similar fish communities may provide a better understanding of the impacts caused by the introduction of non-native invertebrate prey.

Nile tilapia (Oreochromisniloticus) invasion impacts trophic position and resource use of commercially harvested piscivorous fishes in a large subtropical river

BackgroundAlthough freshwater ecosystems cover less than 1% of the earth's surface, they support extremely high levels of biodiversity and provide vital ecosystem services. However, due to the introduction of non-native fishes, aquatic ecosystem functioning has been altered, and in some cases, declined sharply. Quantifying the impacts of invasive species has proven problematic. In this study, we examined the relative trophic position of native piscivorous fishes to estimate the effects of invasive Nile tilapia on food webs in the downstream sections of an invaded large subtropical river, the Pearl River, China. Furthermore, we quantified how native piscivorous fish diets changed as the Nile tilapia invasion progressed.ResultsThe trophic position of the widely distributed and locally important economically harvested piscivorous culter fish (Culterrecurviceps), mandarinfish (Sinipercakneri), and catfish (Pelteobagrusfulvidraco) lowered significantly in the invaded Dongjiang River compared to an uninvaded reference Beijiang River. The lower trophic position of these piscivorous fishes was reflected by a major reduction in the proportion of prey fish biomass in their diets following the Nile tilapia invasion. Small fishes in the diet of culter fish from the reference river (33% small fishes, 17% zooplankton) shifted to lower trophic level zooplankton prey in the invaded river (36% zooplankton, 25% small fish), possibly due to the presence of Nile tilapia. Additionally, small fishes in the diet of mandarinfish in the reference river (46% small fishes, 11% aquatic insects) declined in the invaded river (20% aquatic insects, 30% small fishes). Similarly, the diet of catfish from the reference river shifted from fish eggs (25% fish eggs, 25% aquatic insects) to aquatic insects in the invaded river (44% aquatic insects, 5% fish eggs).ConclusionsThe results of this study contributed to a growing body of evidence, suggesting that Nile tilapia can modify trophic interactions in invaded ecosystems. It is crucial to understand the processes outlined in this study in order to better assess non-native aquatic species, conserve the stability of freshwater ecosystems, and improve current conservation strategies in reaches of the Pearl River and other similar rivers that have experienced invasions of non-native species.

Foreign stingers: South American freshwater river stingrays Potamotrygon spp. established in Indonesia

The pet trade is known to be one of the most important pathways of aquatic non-native species introduction and Indonesia is a significant trade partner. Popular ornamental South American river stingrays (Potamotrygon spp.) were introduced to Indonesia in the 1980s and the culture was established. Here we present a detailed Indonesian market and aquaculture survey, the volume of trade between January 2020 and June 2022, and the list of customer countries with the total amount of imported stingrays. Climate similarities between the native range of P. motoro and P. jabuti and Indonesia were analysed. A significant number of areas of Indonesian islands were identified as suitable for the establishment of this species. This was confirmed by the first record of probably established populations in the Brantas River (Java). In total 13 individuals including newborns were captured. The culture of potamotrygonid stingrays is unregulated in Indonesia, and the risk of the establishment of this predator and its potential spread is alarming for wildlife. Moreover, the first case of envenomation caused by Potamotrygon spp. in the wild outside of South America was recorded. The current condition is predicted as the ‘tip of the iceberg’ and continuous monitoring and mitigation of risks are strongly recommended.

Ecological and Economic Impacts of Alien Invasive Yellow Flag (Iris pseudacorus L.) in China

Non-native aquatic plants can alter the physiochemical condition of habitats and can have negative ecological and economic impacts. Thus, understanding the characteristics of non-native aquatic plant species is important as a foundation for the conservation of biodiversity and environmental management. The yellow flag (Iris pseudacorus) is an emergent aquatic plant native to Africa, northwest Asia, and Europe that has been introduced through the aquarium trade to all continents except Antarctica. This species has recently been brought into China and it has established large and widespread naturalized populations causing serious ecological and environmental problems. Unfortunately, information about the yellow flag in China is very scarce. We summarize the introduction pathways, current distribution, and ecological impacts of the yellow flag through field surveys and a review of the literature. We hope that this study can provide useful information for researchers and wetland managers involved with non-native emergent plants in China and other regions.

Words matter: a systematic review of communication in non-native aquatic species literature

How scientists communicate can influence public viewpoints on invasive species. In the scientific literature, some invasion biologists adopt neutral language, while others use more loaded language, for example by emphasizing the devastating impacts of invasive species and outlining consequences for policy and practice. An evaluation of the use of language in the invasion biology literature does not exist, preventing us from understanding which frames are used and whether there are correlations between message framing in scientific papers and local environmental impacts associated with invasive species. Thus, we conducted a systematic literature review of 278 peer-reviewed articles published from 2008–2018 to understand communication styles adopted by social and natural scientists while reporting on aquatic non-native species research. Species-centered frames (45%) and human-centered frames (55%) were adopted to nearly equal degrees. Negative valence was dominant in that 81.3% of articles highlighted the negative risks and impacts of invasive species. Additionally, the use of terminology was found to broadly align with the stage of invasion, in that “invasive” was most commonly used except when the research was conducted at early stages of invasion, when “non-native” was most commonly used. Terminology use therefore enables readers of scientific papers to infer the status and severity of ongoing invasions. Given that science communication within the peer-reviewed literature affects public understanding of research outcomes, these findings provide an important point of reflection for researchers.

Nonindigenous Aquatic Mollusks in Illinois

Nonindigenous aquatic species (NAS), some of which are referred to as aquatic invasive species (AIS) or non-native aquatic species, are those aquatic organisms that have become established beyond their native ranges. They often inhabit a variety of habitats and physicochemical conditions, reach high densities, and alter ecosystem function. Understanding the distribution of nonindigenous aquatic species is vital to protecting native biodiversity in invaded ecosystems. A search of museum collections, literature accounts, and field surveys conducted in recent years by biologists from the Illinois Natural History Survey, Illinois Department of Natural Resources, and other agencies revealed 13 nonindigenous aquatic mollusk species reported to occur in Illinois. Ten species (five bivalves and five gastropods) have viable reproducing populations. One species, the Big-eared Radix Radix auricularia (Linnaeus, 1758), is no longer extant in Illinois, and two species, the European Stream Valvata Valvata piscinalis (Müller, 1774) and European Fingernail Clam Sphaerium corneum (Linnaeus, 1758), have an unknown status. Some species, such as the Basket Clam Corbicula fluminea (Müller, 1774), Zebra Mussel Dreissena polymorpha (Pallas, 1771), and Chinese Mysterysnail Cipangopaludina chinensis (Gray in Griffith and Pidgeon, 1833), are widespread and abundant. However, other species like the Mottled Fingernail Clam Eupera cubensis (Prime, 1865) and New Zealand Mudsnail Potamopyrgus antipodarum (Gray, 1843) are currently restricted to a particular location or drainage. Other nonindigenous aquatic mollusks with the potential for becoming established in Illinois or border waters are also discussed.

Heavy Metals Assimilation by Native and Non-Native Aquatic Macrophyte Species: A Case Study of a River in the Eastern Cape Province of South Africa

There is continuous deterioration of freshwater systems globally due to excessive anthropogenic inputs, which severely affect important socio-economic and ecological services. We investigated the water and sediment quality at 10 sites along the severely modified Swartkops River system in the Eastern Cape Province of South Africa and then quantified the phytoremediation potential by native and non-native macrophyte species over a period of 6 months. We hypothesized that the presence of semi and permanent native and non-native macrophytes mats would reduce water and sediment contamination through assimilation downriver. Our results were variable and, thus, inconsistent with our hypotheses; there were no clear trends in water and sediment quality improvement along the Swartkops River. Although variable, the free-floating non-native macrophyte, Pontederia (=Eichhornia) crassipes recorded the highest assimilation potential of heavy metals in water (e.g., Fe and Cu) and sediments (e.g., Fe and Zn), followed by a submerged native macrophyte, Stuckenia pectinatus, and three native emergent species, Typha capensis, Cyperus sexangularis, and Phragmites australis. Pollution indices clearly showed the promising assimilation by native and non-native macrophytes species; however, the Swartkops River was heavily influenced by multiple non-point sources along the system, compromising the assimilation effect. Furthermore, we emphasise that excessive anthropogenic inputs compromise the system’s ability to assimilate heavy metals inputs leading to water quality deterioration.

Editorial: Understanding the Impact and Invasion Success of Aquatic Non-native Species: How They Interact With Novel Environments and Native Biota

Editorial: Understanding the Impact and Invasion Success of Aquatic Non-native Species: How They Interact With Novel Environments and Native Biota

Pathogens co-transported with invasive non-native aquatic species: implications for risk analysis and legislation

Invasive Non-Native Species (INNS) can co-transport externally and internally other organisms including viruses, bacteria and other eukaryotes (including metazoan parasites), collectively referred to as the symbiome. These symbiotic organisms include pathogens, a small minority of which are subject to surveillance and regulatory control, but most of which are currently unscrutinized and/or unknown. These putatively pathogenetic symbionts can potentially pose diverse risks to other species, with implications for increased epidemiological risk to agriculture and aquaculture, wildlife/ecosystems, and human health (zoonotic diseases). The risks and impacts arising from co-transported known pathogens and other symbionts of unknown pathogenic virulence, remain largely unexplored, unlegislated, and difficult to identify and quantify. Here, we propose a workflow using PubMed and Google Scholar to systematically search existing literature to determine any known and potential pathogens of aquatic INNS. This workflow acts as a prerequisite for assessing the nature and risk posed by co-transported pathogens of INNS; of which a better understanding is necessary to inform policy and INNS risk assessments. Addressing this evidence gap will be instrumental to devise an appropriate set of statutory responsibilities with respect to these symbionts, and to underpin new and more effective legislative processes relating to the disease screening and risk assessment of INNS.

Pathogens co-transported with invasive non-native aquatic species: implications for risk analysis and legislation

Invasive Non-Native Species (INNS) can co-transport externally and internally other organisms including viruses, bacteria and other eukaryotes (including metazoan parasites), collectively referred to as the symbiome. These symbiotic organisms include pathogens, a small minority of which are subject to surveillance and regulatory control, but most of which are currently unscrutinized and/or unknown. These putatively pathogenetic symbionts can potentially pose diverse risks to other species, with implications for increased epidemiological risk to agriculture and aquaculture, wildlife/ecosystems, and human health (zoonotic diseases). The risks and impacts arising from co-transported known pathogens and other symbionts of unknown pathogenic virulence, remain largely unexplored, unlegislated, and difficult to identify and quantify. Here, we propose a workflow using PubMed and Google Scholar to systematically search existing literature to determine any known and potential pathogens of aquatic INNS. This workflow acts as a prerequisite for assessing the nature and risk posed by co-transported pathogens of INNS; of which a better understanding is necessary to inform policy and INNS risk assessments. Addressing this evidence gap will be instrumental to devise an appropriate set of statutory responsibilities with respect to these symbionts, and to underpin new and more effective legislative processes relating to the disease screening and risk assessment of INNS.

An assessment of regulation, education practices and socio-economic perceptions of non-native aquatic species in the Balkans

Alongside climate change, the introduction of non-native species (NNS) is widely recognized as one of the main threats to aquatic biodiversity and human wellbeing. Non-native species and biodiversity are generally low priority issues on the political agendas of many countries, particularly in European countries outside the European Union (EU). The objectives and tasks of this study were to address the policy regulation, education level, education practices, and socioeconomic perceptions of NNS in the Balkans. A questionnaire-based survey was conducted in Albania, Bosnia and Herzegovina, Montenegro, North Macedonia and Turkey (Balkan EU candidate and potential candidate members), in Croatia and Greece (Balkan EU Member States) and Italy (non-Balkan EU Member State). The EU Alien Regulation (1143/2014) concerning NNS is implemented in EU Member States and Montenegro, whereas Albania, Bosnia and Herzegovina and Turkey have not reported specific policy regulations for NNS. Permanent monitoring programmes specifically designed for NNS have not yet been established in the EU Member States. Most countries tackle the issue of NNS through educational activities as part of specific projects. Education level is indicative of the implementation of NNS policy regulation, and efforts are needed for the proper development of relative study programmes. Public awareness and educational preparedness concerning NNS in the Balkans were identified as poor. Strong programmes for management and education should be developed to increase public awareness to prevent further biodiversity losses in the Balkan region.

Publisher Correction: Risk screening of the potential invasiveness of non-native aquatic species in Vietnam

Publisher Correction: Risk screening of the potential invasiveness of non-native aquatic species in Vietnam

Risk screening of the potential invasiveness of non-native aquatic species in Vietnam

The impact of non-native species, together with their pervasiveness, necessitates a means of identifying which species are most likely to pose an elevated risk of becoming invasive. This is amongst the first applications of the Aquatic Species Invasiveness Screening Kit (AS-ISK) decision support tool in Southeast Asia, and specifically for Vietnam. In total, 30 extant and horizon non-native aquatic species were screened for their potential invasiveness in Vietnam. A threshold score of 6.75 was identified for distinguishing between species likely to pose a high and low-to-medium risk of becoming invasive in Vietnam for both the basic risk assessment (BRA) and the climate change assessment (BRA + CCA) components of the screening process. However, the absence of nationally-consistent predictions on climate change impacts in Vietnam restricted the applicability of the climate change assessment component. Based on the BRA threshold, of the 30 species screened, 25 were classified as high risk, four as medium risk, and one as low risk. For the BRA, the highest-scoring species were Hypostomus plecostomus, Pomacea canaliculata and Lithobates catesbeianus. This study reliably identified and discriminated between non-invasive and potentially invasive aquatic species in Vietnam, thereby providing appropriate AS-ISK score thresholds with which to guide policy and decision-making. This suggests that the AS-ISK could be successfully employed to screen non-native aquatic species in other parts of Southeast Asia.