Pacifastacus Leniusculus Research Articles

Ecosystem effects of invasive crayfish increase with crayfish density

Abstract The nature and extent of effects of increasing densities of non‐native species on stream ecosystems remain poorly understood. Non‐native crayfish are among the most invasive aquatic species and we hypothesised that, in temperate streams, the extent of trophic modification increases with non‐native crayfish density. Instream flow‐through mesocosms in the River Lune, north‐east England, were used over a 47‐day period in summer to measure density effects of invasive signal crayfish Pacifastacus leniusculus on different ecosystem components (benthic fish, macroinvertebrates, algal biomass, and leaf litter breakdown). Effects were measured through three density treatments (low, medium, and high; four, eight, or 12 crayfish with five bullhead Cottus perifretum per 1.5 m2) and two control (crayfish and fish absent; crayfish absent and benthic fish present) groups. Impacts of crayfish on macroinvertebrates (density, taxonomic composition), fish (growth, diet), algal standing stock, and decomposition rates increased with crayfish density. Direct effects of increased crayfish density were more important than indirect trophic cascade effects. Despite similar invertebrate abundance and richness across enclosures before introducing crayfish and bullhead, they differed significantly from controls at the end of the study, with >80% reduction in macroinvertebrate abundance recorded in the high‐density group. Stable isotope (δ15N, δ13C) analysis showed that the trophic niche of bullhead, but not signal crayfish, changed when the species were in sympatry. Bullhead in treatment enclosures occupied a lower trophic position in the food web than those from the control group. Bullhead in the high‐density group lost 4.2% of body mass over the study period, confirming the existence of resource competition. Leaf litter break down was 59.2% faster, and algal biomass was 91.4% lower in the treatment with the highest crayfish density compared to the control without study animals. This study indicates that signal crayfish, even at a low density, can strongly alter multiple ecosystem components in streams, and emphasises the need for minimising the spread of invasive crayfish within and between streams.

Effects of selenium treatment on endogenous antioxidant capacity in signal crayfish (Pacifastacus leniusculus)

Selenium is an essential element that plays a role in numerous physiological processes and is critical for the maintenance of a strong endogenous antioxidant system. Previous work by our research group reported that the organophosphate pesticide dimethoate decreased glutathione S-transferase activity (GST) in signal crayfish (Pacifastacus leniusculus) collected from the Boise River (Idaho, USA). The goals of this study were to examine whether: 1) sodium selenite modulated the endogenous antioxidants glutathione (GSH), metallothionein (MT), and glutathione S-transferase (GST), thus suggesting a mechanism of antioxidant activity, 2) dimethoate exposure (pro-oxidant stressor) decreased GST activity in a localized population of signal crayfish collected from the Snake River (Idaho, USA), and 3) investigate whether selenium cotreatment ameliorated the adverse effects of dimethoate on GST activity due to the antioxidant properties associated with selenium. Selenium and dimethoate treatments (and co-treatments) did not modulate GSH or MT concentrations at the doses tested in this study. Furthermore, neither selenium nor dimethoate was factors influencing GST activity, and no interaction was found between the treatments. While our results did not support our predictions, they are suggestive and future studies examining the protective role of selenium in pro-oxidant exposure in this species are warranted. Population-specific responses as well as seasonal variations in endogenous antioxidant expression should be considered in future experiments.

Combined per‐capita and abundance effects of an invasive species on native invertebrate diversity and a key ecosystem process

Abstract Invasive alien species (IAS) are leading to the homogenisation of taxonomic and functional biodiversity, with negative consequences for key ecosystem processes in fresh water. Invasive signal crayfish (Pacifastacus leniusculus) is expected to disrupt detritus‐based food webs by affecting leaf breakdown and/or by decreasing invertebrate density and diversity through predation. The combination of per‐capita and abundance effects of P. leniusculus in invaded ecosystems is still largely unknown. A four‐week field experiment was established in Rabaçal and Tuela Rivers (NE Portugal) to assess effects of P. leniusculus on invertebrate taxonomic and functional diversity and leaf litter breakdown following a gradient of invasion. We controlled the presence and absence of crayfish by placing the animals and leaf litter inside cages at six sites (three sites per river) according to the crayfish in situ abundance (absent, low, high). Cages were covered with coarse‐ or fine‐mesh net to allow or prevent invertebrates from accessing the leaves. Results showed that higher crayfish in situ abundance led to a decrease in abundance, richness and Shannon diversity of invertebrates and to changes in the communities’ structures. Higher crayfish abundance led also to a decrease in invertebrate functional redundancy and an increase in the percentage of invertebrate taxa with resistance forms. Leaf litter breakdown increased with crayfish presence and decreased at sites with higher crayfish abundance. Overall, signal crayfish changed the community structure of invertebrates, with potential severe long‐term effects on native communities and leaf litter breakdown. Given the widespread distribution of signal crayfish (and other crayfish species), their ecological impacts should be assessed carefully, especially in pristine freshwater ecosystems such as those described here.

Variations in host surfaces morphology and biology of ciliate epibionts explaining distribution pattern of epibionts in the invasive signal crayfish Pacifastacus leniusculus (Dana, 1852)

AbstractThe present paper reports the distribution of Epistylididae (Sessilida) epibiotic ciliates on the signal crayfish Pacifastacus leniusculus in relation to specialized structures of the host's exoskeleton for the first time. This species is known to maintain a relatively clean carapace, but it is sometimes overgrown by other organisms. Epibionts cover different parts of the signal crayfish body, mainly antennae, antennules, maxillipedes III and pereiopods with inner edges of chelae; however, some parts of the signal crayfish are not fouled. e.g. dorsal surfaces of the carapace and dorsal surfaces of chelae. Using scanning electron microscopy (SEM), topographies of different parts of the crayfish's exoskeleton were examined. Our investigations revealed that the epibiosis in the signal crayfish was determined by morphology of body surfaces. No epibionts were found on smooth surfaces with regular single setae (a known design that prevents fouling in aquatic environments). The dimpled surfaces with regular single micro‐papillae may be considered as a newly described example of self‐cleaning surfaces. Bio‐inspired surface patterning presents promising approaches to the design of novel functional surfaces that can prevent biofouling. The new self‐cleaning design may be used in further technological applications.

Cardiac activity with acute exposure to sub-zero temperatures illustrates the survival mechanism of invasive crayfish

The ability to withstand climate and weather extremes can play a key role in survival and establishment of non-native species. We investigated the effect of acute exposure to sub-zero temperature on the heart rate and recovery capacity of invasive crayfish Faxonius limosus, Pacifastacus leniusculus, and Procambarus clarkii. The experiments used non-invasive sensors to assess cardiac activity relative to survival and recovery of crayfish during short (30 min) and prolonged (60 min) exposures to − 18 °C. All P. clarkii specimens survived freezing temperature and rewarming and recovered after the short exposure, and 25% recovered after prolonged exposure. All F. limosus and P. leniusculus died during the recovery period following both exposures. In all tested specimens a heartbeat was measurable several hours after conclusion of exposure, gradually declining in F. limosus and P. leniusculus. The P. clarkii heart rate decreased abruptly upon exposure to sub-zero temperature, and recovery to nearly the pre-exposure rate took longer than for F. limosus and P. leniusculus. Heartbeat decline slopes were as follows: P. clarkii, 80.2° ± 2.1°, > F. limosus, 74.9° ± 4.1°, > P. leniusculus, 70.3° ± 3.7°. During the cooling-warming cycle, F. limosus and P. leniusculus demonstrated more gradual heartbeat decline and more rapid recovery to original levels but ultimately did not survive, most likely due to energy depletion associated with heartbeat fluctuation while cooling. These findings may increase our understanding of the broader distribution of P. clarkii than expected according to its ecological optima and provide insight into the mechanisms of invasive crayfish adaptability.

Personality, density and habitat drive the dispersal of invasive crayfish

There is increasing evidence that personality traits may drive dispersal patterns of animals, including invasive species. We investigated, using the widespread signal crayfish Pacifastacus leniusculus as a model invasive species, whether effects of personality traits on dispersal were independent of, or affected by, other factors including population density, habitat, crayfish size, sex and limb loss, along an invasion gradient. Behavioural traits (boldness, activity, exploration, willingness to climb) of 310 individually marked signal crayfish were measured at fully-established, newly-established and invasion front sites of two upland streams. After a period at liberty, recaptured crayfish were reassessed for behavioural traits (newly-established, invasion front). Dispersal distance and direction of crayfish movement, local population density, fine-scale habitat characteristics and crayfish size, sex and limb loss were also measured. Individual crayfish exhibited consistency in behavioural traits over time which formed a behavioural syndrome. Dispersal was both positively and negatively affected by personality traits, positively by local population density and negatively by refuge availability. No effect of size, sex and limb loss was recorded. Personality played a role in promoting dispersal but population density and local habitat complexity were also important determinants. Predicting biological invasion in animals is likely to require better integration of these processes.

Environmental DNA‐based methods detect the invasion front of an advancing signal crayfish population

AbstractAquatic invasive species, such as the signal crayfish (Pacifastacus leniusculus), present a major threat to freshwater ecosystems. However, these species can be challenging to detect in recently invaded habitats. Environmental DNA (eDNA)–based methods are highly sensitive and capable of detecting just a few copies of target DNA from non‐invasively collected samples. Therefore, they have considerable potential for broad‐scale use in mapping and monitoring the spread of invasive species. In this study, we aimed to increase our understanding of the current distribution of signal crayfish in a headwater stream system in the United Kingdom (tributaries of the River Wharfe, Addingham, Yorkshire). Environmental DNA sampling, assessment of water chemistry variables, and conventional crayfish hand‐searching were conducted across 19 study sites in five tributary streams. Using hand‐searching, we detected signal crayfish at 26% of the sites (5/19 study sites). However, using eDNA‐based methods, occupancy increased to 47% of study sites (9/19). Our sampling revealed previously unknown sites of crayfish occupancy, and using eDNA‐based methods, we were able to define the geographical extent of the invasion front in each headwater stream sampled. This study highlights that eDNA‐based methods are well‐suited for detecting newly established signal crayfish populations in recently invaded habitats, even when the invasive species is at low abundance and, therefore, might otherwise be under‐represented or undetected using conventional survey methods. Our study provides further evidence that headwater stream ecosystems are particularly vulnerable to signal crayfish invasion. However, their geomorphological features may make methods used to reduce or prevent invasive crayfish dispersal more effective than in other freshwater ecosystems.

Mechanical male sterilisation in invasive signal crayfish Pacifastacus leniusculus: persistence and functionality in captive and wild conditions

Management control methods for invasive crayfish remain of limited effectiveness, resulting in ongoing invasions of high ecological impact. As management programmes integrating methods to limit juvenile recruitment could reduce population abundances, the efficacy of a sterile male release technique (SMRT) based on the manual removal of male gonopods was tested here in captive and wild conditions by comparing the survival, gonopod regeneration rates and a range of reproductive metrics of sterilised versus non-sterilised males. Sterilised male survival was high, with their removed gonopods regenerating at sizes that were always smaller than those of non-sterilised males. In captive trials, while sterilised males showed significantly lower areas of spermatophore cover than non-sterilised, and less accuracy in placement, subsequent female brood size did not differ significantly between the two male groups. The number of females retaining their clutches also did not also differ significantly between these groups. Over a seven-year period in the wild, there was no evidence suggesting SMRT significantly reduced female brood sizes and clutch retention rates. Although mechanical SMRT altered the size and delivery accuracy of sterilised male gonopods, female reproductive success of invasive crayfish was unaffected. Several potential reasons for this failure of the technique were identified and require further research.

Salinity tolerance of the alien branchiobdellidan Sathodrilus attenuatus (Annelida: Clitellata) on the introduced freshwater crayfish Pacifastacus leniusculus (Crustacea: Decapoda) in eastern Hokkaido, Japan and the pathway of introduction of the host to Lake Harutori and adjacent freshwaters in Kushiro City, eastern Hokkaido

Salinity tolerance of the alien branchiobdellidan <i>Sathodrilus attenuatus</i> (Annelida: Clitellata) on the introduced freshwater crayfish <i>Pacifastacus leniusculus</i> (Crustacea: Decapoda) in eastern Hokkaido, Japan and the pathway of introduction of the host to Lake Harutori and adjacent freshwaters in Kushiro City, eastern Hokkaido

Physiological performance of native and invasive crayfish species in a changing environment: insights from Dynamic Energy Budget models.

Crayfish are keystone species important for maintaining healthy freshwater ecosystems. Crayfish species native to Europe, such as Astacus astacus and Austropotamobius torrentium, are facing decline and are increasingly endangered by changing climate and invasions of non-native crayfish, such as Pacifastacus leniusculus and Procambarus virginalis. The success of these invasions largely depends on differences in ontogeny between the native species and the invaders and how changes in the environment will affect the ontogeny. Dynamic Energy Budget (DEB) models can be used to investigate such differences because the models capture dependence of metabolism, and therefore ontogeny, on environmental conditions. We develop DEB models for all four species and investigate key elements of ontogeny and metabolism affecting interspecific competition. We then use the DEB models to predict individual growth and reproduction in current and new conditions that are expected to arise from climate change. Although observations suggest that P. leniusculus poses the major threat to native species, our analysis identifies P. virginalis, in spite of its smaller size, as the superior competitor by a large margin—at least when considering metabolism and ontogeny. Our simulations show that climate change is set to increase the competitive edge of P. virginalis even further. Given the prospects of P. virginalis dominance, especially when considering that it is able to withstand and spread at least some crayfish plague strains that severely affect native species, additional research into P. virginalis is necessary.

Responses of Signal Crayfish Pacifastacus Leniusculus to Pulse Exposure of Pesticides at Environmentally Relevant Concentrations

Responses of Signal Crayfish Pacifastacus Leniusculus to Pulse Exposure of Pesticides at Environmentally Relevant Concentrations

Integrated Biomarker Response in Signal Crayfish Pacifastacus Leniusculus Exposed to Diphenhydramine

Integrated Biomarker Response in Signal Crayfish Pacifastacus Leniusculus Exposed to Diphenhydramine

Management of invasive, plague-carrying signal crayfish by physical exclusion barriers

Management of invasive, plague-carrying signal crayfish by physical exclusion barriers

Identifying economic costs and knowledge gaps of invasive aquatic crustaceans

Despite voluminous literature identifying the impacts of invasive species, summaries of monetary costs for some taxonomic groups remain limited. Invasive alien crustaceans often have profound impacts on recipient ecosystems, but there may be great unknowns related to their economic costs. Using the InvaCost database, we quantify and analyse reported costs associated with invasive crustaceans globally across taxonomic, spatial, and temporal descriptors. Specifically, we quantify the costs of prominent aquatic crustaceans — crayfish, crabs, amphipods, and lobsters. Between 2000 and 2020, crayfish caused US$ 120.5 million in reported costs; the vast majority (99%) being attributed to representatives of Astacidae and Cambaridae. Crayfish-related costs were unevenly distributed across countries, with a strong bias towards European economies (US$ 116.4 million; mainly due to the signal crayfish in Sweden), followed by costs reported from North America and Asia. The costs were also largely predicted or extrapolated, and thus not based on empirical observations. Despite these limitations, the costs of invasive crayfish have increased considerably over the past two decades, averaging US$ 5.7 million per year. Invasive crabs have caused costs of US$ 150.2 million since 1960 and the ratios were again uneven (57% in North America and 42% in Europe). Damage-related costs dominated for both crayfish (80%) and crabs (99%), with management costs lacking or even more under-reported. Reported costs for invasive amphipods (US$ 178.8 thousand) and lobsters (US$ 44.6 thousand) were considerably lower, suggesting a lack of effort in reporting costs for these groups or effects that are largely non-monetised. Despite the well-known damage caused by invasive crustaceans, we identify data limitations that prevent a full accounting of the economic costs of these invasive groups, while highlighting the increasing costs at several scales based on the available literature. Further cost reports are needed to better assess the true magnitude of monetary costs caused by invasive aquatic crustaceans.

Response of freshwater snails to invasive crayfish varies with physiochemical exposure cues and predator experience

Abstract Invasive species represent one of the greatest threats to freshwater biodiversity. The successful colonisation and establishment of populations of invasive predators in waterbodies may expose the pre‐existing fauna to novel predation strategies to which they are not pre‐adapted. Despite this, there is still a paucity of information on behavioural responses within biological invasion research. Here we present the results of a series of 24‐hr mesocosm experiments that examined the handling times and responses of four Gastropoda species (Radix balthica, Physa fontinalis, Gyraulus albus, Potamopyrgus antipodarum) exposed to physical and chemical cues associated with the invasive crayfish, Pacifastacus leniusculus. We specifically considered four physicochemical treatments: (1) control (no cue); (2) conspecific chemical; (3) crayfish chemical; and (4) physical presence (but confined). In addition, we considered the effect of previous predator experience of the gastropod (predator naïve or aware) and additonally assessed survivourship in encounter trials. Handling time was found to vary significantly between gastropod species with survivorship from predation mirroring handling times observed. P. fontinalis required the greatest handling time (average of 58 s) and had the highest survivorship rate. In marked contrast, P. antipodarum were rapidly consumed, with an average handling time of 6 s and no individuals surviving after 4‐hr in the encounter trials. Handling time varied by gastropod size but also shell morphology. The response to the physical and chemical cues varied between gastropod species. R. balthica and P. fontinalis demonstrated vertical avoidance behaviour most readily whilst P. albus and P. antipodarum displayed active migration only to the physical presence cue. In most instances, the response was immediate with vertical migration (above the reach of the crayfish at 15 cm on the mesocosm wall) evident within an hour. Predation regime was found to exert a significant effect on the avoidance response of the gastropods. This was particularly notable in relation to the crayfish chemical cue and to a lesser extent the injured conspecific chemical cue. Predator‐naïve populations reacted with strong vertical avoidance behaviour in response to the crayfish chemical cue, whilst, in the case of P. fontinalis, predator aware individuals reacted most strongly to the conspecific chemical cue. Our results highlight the multifaceted challenge of understanding predator–prey relationships, particularly in the face of novel invasive species, and provide much‐needed evidence to begin to tackle this complex process. Gaining a better understanding of such interactions is vital in order to underpin management strategies and to enable evolutionary trajectories in invaded ecosystems to be assessed. Previous predator experience in combination with species identity are important attributes in determining predation risk when gastropod populations are exposed to novel predators and their associated predation cues.

Divergent temperature-specific metabolic and feeding rates of native and invasive crayfish

Temperature is one of the most important factors governing the activity of ectothermic species, and it plays an important but less studied role in the manifestation of invasive species impacts. In this study, we investigated temperature-specific feeding and metabolic rates of invasive and native crayfish, and evaluated how temperature regulates their ecological impacts at present and in future according to different climatic scenarios by bioenergetics modelling. We conducted a series of maximum food consumption experiments and measured the metabolic rates of cold-adapted native noble crayfish (Astacus astacus) and invasive signal crayfish (Pacifastacus leniusculus) originally from a warmer environment over a temperature gradient resembling natural temperatures in Finland. The maximum feeding rates and routine metabolic rates (RMR) of native noble crayfish were significantly higher at low temperatures (< 10 °C than the rates of invasive signal crayfish. The RMRs of the species crossed at 18 °C, and the RMRs of signal crayfish were higher at temperatures above 18 °C. These findings indicate that the invader’s thermal niche has remained stable, and the potential impacts per capita are lower at suboptimal cold temperatures than for the native species. Our bioenergetics modelling showed that the direct annual predation impact of noble and signal crayfish seem similar, although the seasonal dynamics of the predation differs considerably between species. Our results highlight that the temperature-specific metabolic and feeding rates of species need to be taken into account in the impact assessment instead of simple generalisations of the direction or magnitude of impacts.

Impacts of native and invasive crayfish on three native and one invasive freshwater mussel species

Abstract Freshwater mussels and crayfish provide important ecosystem functions and services. In both groups, global declines of native species are paralleled by invasions of non‐native species. Knowledge on differences in predation susceptibility of native and invasive freshwater mussels exposed to native and invasive crayfish is essential for understanding their ecological interactions and for conservation management. In this study, we compared the predation impact of the native European noble crayfish (Astacus astacus) and the invasive signal crayfish (Pacifastacus leniusculus) on three native (Anodonta anatina, Anodonta cygnea, and Unio pictorum) and one invasive (Sinanodonta woodiana) mussel species in controlled laboratory experiments. We repeated the same experiments with the same crayfish specimens to investigate a potential learning effect of crayfish and assessed the in situ impacts in a natural stream. Mussel predation and damage caused by P. leniusculus was significantly higher than by A. astacus. Irrespective of the crayfish species, susceptibility was greater in native mussel species compared to invasive S. woodiana. Predation and damage was greatest in the thick‐shelled U. pictorum, suggesting that other factors such as shell shape are more important in explaining susceptibility than shell thickness. A predation learning effect from previous co‐exposure was evident, being most pronounced for A. astacus. Even if our experimental findings could not be confirmed in the field, the experimental results suggest that crayfish may have a negative impact on mussels and this impact will likely increase with the ongoing spread of P. leniusculus replacing A. astacus populations in Europe. The co‐occurrence of invasive P. leniusculus with the invasive S. woodiana could potentially exacerbate declines of endangered native mussel populations.

Virome Analysis of Signal Crayfish (Pacifastacus leniusculus) along Its Invasion Range Reveals Diverse and Divergent RNA Viruses.

Crayfish are a keystone species of freshwater ecosystems and a successful invasive species. However, their pathogens, including viruses, remain understudied. The aim of this study was to analyze the virome of the invasive signal crayfish (Pacifastacus leniusculus) and to elucidate the potential differences in viral composition and abundance along its invasion range in the Korana River, Croatia. By the high-throughput sequencing of ribosomal RNA, depleted total RNA isolated from the crayfish hepatopancreas, and subsequent sequence data analysis, we identified novel and divergent RNA viruses, including signal crayfish-associated reo-like, hepe-like, toti-like, and picorna-like viruses, phylogenetically related to viruses previously associated with crustacean hosts. The patterns of reads abundance and calculated nucleotide diversities of the detected viral sequences varied along the invasion range. This could indicate the possible influence of different factors and processes on signal crayfish virome composition: e.g., the differences in signal crayfish population density, the non-random dispersal of host individuals from the core to the invasion fronts, and the transfer of viruses from the native co-occurring and phylogenetically related crayfish species. The study reveals a high, previously undiscovered diversity of divergent RNA viruses associated with signal crayfish, and sets foundations for understanding the potential risk of virus transmissions as a result of this invader’s dispersal.

Disturbance in invasion? Idiopathic necrotizing hepatopancreatitis in the signal crayfish Pacifastacus leniusculus (Dana, 1852) in Croatia.

As the most successful crayfish invader and possible vector for infectious agents, signal crayfish Pacifastacus leniusculus is among the major drivers of the native crayfish species decline in Europe. We describe histopathological manifestation and frequency of newly detected idiopathic necrotizing hepatopancreatitis along the invasion range of the signal crayfish in the Korana River in Croatia. Our results show extremely high prevalence of necrotizing hepatopancreatitis (97.3%), with 58.9% of individuals displaying mild and 31.5% moderate histopathological changes in the hepatopancreas, also reflected in the lower hepatosomatic index of analysed animals. Recorded histopathological changes were more frequent in the invasion core where population density is higher. Our preliminary screening of co-occurring native narrow-clawed crayfish Pontastacus leptodactylus showed lower incidence (33.3%) and only mild hepatopancreatic lesions, but potentially highlighted the susceptibility of native crayfish populations to this disease. Pilot analyses of dissolved trace and macro elements in water, sediment fractions and crayfish hepatopancreas do not highlight alarming or unusually high concentrations of analysed elements. Hepatopancreas microbiome analysis, using 16S rRNA gene amplicon sequencing, identified taxonomic groups that should be further investigated, along with impacts of the disease on health and viability of both invasive and native crayfish populations.

Impacts Analysis of Alien Macroinvertebrate Species in the Hydrographic System of a Subalpine Lake on the Italian–Swiss Border

The potential invasiveness of alien macroinvertebrate species in the Italian/Swiss hydrographic system of Lake Maggiore (NW Italy) was assessed through the Aquatic Species Invasiveness Screening Kit, a risk assessment tool developed for quantifying the impacts of alien species on the commercial, environmental, and species traits sectors. Data were collected using the databases provided by two regional environmental agencies in northern Italy (Lombardy and Piedmont regions) and by the governmental monitoring program of Switzerland, which were integrated with a systematic literature search on Google scholar and ISI Web of Science. In the assessment area, 16 macroinvertebrate invasive alien species were reported: nine mollusks, four decapods, and three amphipods. The species assessment indicated seven species with a high level of invasiveness: Procambarus clarkii, Faxonius limosus (formerly, Orconectes limosus) and Pacifastacus leniusculus, Dreissena polymorpha, Corbicula fluminea, Sinanodonta woodiana, and Pseudosuccinea columella. The results allow invasive species managers to understand which species to focus their monitoring on in the near future in order to track IAS movements and limit their spread within the hydrographic system and to provide the identification and refinement of concerted bilateral strategies aimed at limiting the impacts of these species. They also account for the implications of future climate change on the invasion potential of each species.