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Marinas contribute to the degradation of coastal ecosystems, constitute non-indigenous species (NIS) hotspots and function as steppingstones in invasion processes. These often enclose highly modified water bodies that promote the concentration of pollutants and propagules, favoring NIS abundance. In these habitats, floating structures are often the most invaded by fouling NIS. This study aims to address the effect of floating substrate (buoys vs pontoons) on fouling assemblages, with special focus on NIS, in 6 marinas of Cadiz Bay during summer and winter seasons. Since the effect substrate type can depend on the water physicochemical conditions and environmental state and pressures of marinas, an environmental assessment was carried out for each marina using literature, physicochemical water measurements and environmental risk assessments. Despite the registered seasonal variation in fouling assemblages and the environmental variability among the studied marinas, the type of substrate played a key role in fouling assemblages' structure and abundance. The higher abundance of fouling assemblages in buoys than pontoons favor NIS prevalence in marinas and increase the risk of NIS dispersal, particularly considering that buoys are more likely to detach and drift at sea than pontoons. The results indicate that high-risk consideration should be given to this substrate type and that the potential environmental effects of biological pollution must be considered in risk assessments

General context: Gulls ingest plastic and other litter while foraging in open landfills, because organic matter is mixed with other debris. Therefore, gulls are potential biovectors of plastic pollution into natural habitats, especially when they concentrate in wetlands for roosting. Novelty: We quantified, for the first time, the flow of plastic and other anthropogenic debris from open landfills to a natural lake via the movement of gulls. We focused on Fuente de Piedra, an inland closed-basin lake in Spain that is internationally important for biodiversity. Methodology: In 2022, we sampled gull pellets regurgitated in the lake by lesser black-backed gulls Larus fuscus that feed on landfills, as well as their faeces, then characterized and quantified debris particles of ≥0.5 mm. By combining GPS and census data from 2010 to 2022, together with plastic quantification based on FTIR-ATR analysis, we estimated the average annual deposition of plastic and other debris by the wintering gull population into the lake. Main results: 86 % of pellets contained plastics, and 94 % contained other debris such as glass and textiles. Polyethylene (54 %), polypropylene (11.5 %) and polystyrene (11.5 %) were the main plastic polymers. An estimated annual mean of 400 kg of plastics were moved by gulls into the lake. Only 1 % of plastic mass was imported in faeces. Discussion: Incorporating the biovectoring role of birds can provide a more holistic view of the plastic cycle and waste management. Biovectoring is predictable in sites worldwide where gulls and other waterbirds feed in landfills and roost in wetlands. We discuss bird deterrence and other ways of mitigating debris leakage into aquatic ecosystems

Funding This research was supported by the LIFE INVASAQUA project (Aquatic In- vasive Alien Species of Freshwater and Estuarine Systems: Awareness and Prevention in the Iberian Peninsula) (LIFE17 GIE/ES/000515) funded by the EU LIFE Program. The Fundación Biodiversidad (Government of Spain) and the Government of Navarre financially support specific actions into the LIFE INVASAQUA. F.R. is supported by Foundation for Science and Technology through an individual contract (CEEC/0482/2020). J.E. has a Ph.D. scholarship (SFRH/BD/140556/2018) funded by FCT, Portugal. F.B. is supported by Foundation for Science and Technology through an individual contract (CEEC/01896/2021)., As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts, greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants, freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through various pathways from different regions of the world and classified according to their main functional feeding groups. Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12 top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decision-makers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for pot, European Commission, Fundación Biodiversidad, Nafarroako Gobernua, Fundación para la Ciencia y la Tecnología, Foundation for Science and Technology (Portugal), Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

This study was supported by the LIFE INVASAQUA project (Aquatic Invasive Alien Species of Freshwater and Estuarine Systems: Awareness and Prevention in the Iberian Peninsula) (LIFE17 GIE/ES/000515) funded by the EU LIFE Program. The Fundación Biodiversidad (Government of Spain) and the Government of Navarre financially supported specific actions into the LIFE INVASAQUA. J.M. Z.-M. is supported by a postdoctoral grant funded by the Spanish Ministry of Science and Innovation and the European Union NextGeneration EU/PRTR (FJC2021-046923-I). F.R. is supported by Foundation for Science and Technology through an individual contract (CEEC/0482/2020). I.B. and J.A.C. were funded by the Basque Government (IT1487-22). J.E. has a Ph.D. scholarship (SFRH/BD/140556/2018) funded by FCT, Portugal. F.B. is supported by Foundation for Science and Technology through an individual contract (CEEC/01896/2021). C.C. was supported by Portuguese national funds to the CEG/IGOT Research Unit (UIDB/00295/2020 and UIDP/00295/2020), through FCT - Fundação para a Ciência e a Tecnologia, I.P. F.C.A, was funded by CEF, a research unit of FCT, Portugal (UIDB/00239/2020). A.A. H.-R. was supported by a predoctoral grant from the University of Murcia (R-483/2023)., Aquatic ecosystems are particularly vulnerable to the introduction of non-indigenous species (NIS), leading to multi-faceted ecological, economic and health impacts worldwide. The Iberian Peninsula comprises an exceptionally biodiverse Mediterranean region with a high number of threatened and endemic aquatic species, most of them strongly impacted by biological invasions. Following a structured approach that combines a systematic review of available information and expert opinion, we provide a comprehensive and updated multi-taxa inventory of aquatic NIS (fungi, macroalgae, vascular plants, invertebrates and vertebrates) in Iberian inland waters. Moreover, we assess overall patterns in the establishment status, introduction pathways, native range and temporal introduction trends of listed NIS. In addition, we discuss the legal coverage provided by both national (Spanish and Portuguese) and European NIS regulations. We inventoried 326 aquatic NIS in Iberian inland waters, including 215 established, 96 with uncertain establishment status and 15 cryptogenic taxa. Invertebrates (54.6%) and vertebrates (24.5%) were the groups with the highest number of NIS, with Arthropoda, Mollusca, and Chordata being the most represented phyla. Recorded NIS originated from diverse geographic regions, with North and South America being the most frequent. Vertebrates and vascular plants were mostly introduced through intentional pathways (i.e. release and escape), whereas invertebrates and macroalgae arrived mostly through unintentional ways (i.e. contaminant or stowaway). Most of the recorded NIS were introduced in Iberian inland waters over the second half of the 20th century, with a high number of NIS introductions being reported in the 2000s. While only 8% of the recorded NIS appear in the European Union list of Invasive Alien Species of Union concern, around 25% are listed in the Spanish and Portuguese NIS regulations. This study provides the most updated checklist of Iberian aquati, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Gobierno de Navarra, Eusko Jaurlaritza, Portuguese Foundation for Science and Technology, Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Funding This research was supported by the LIFE INVASAQUA project (Aquatic In- vasive Alien Species of Freshwater and Estuarine Systems: Awareness and Prevention in the Iberian Peninsula) (LIFE17 GIE/ES/000515) funded by the EU LIFE Program. The Fundación Biodiversidad (Government of Spain) and the Government of Navarre financially support specific actions into the LIFE INVASAQUA. F.R. is supported by Foundation for Science and Technology through an individual contract (CEEC/0482/2020). J.E. has a Ph.D. scholarship (SFRH/BD/140556/2018) funded by FCT, Portugal. F.B. is supported by Foundation for Science and Technology through an individual contract (CEEC/01896/2021)., As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts, greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants, freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through various pathways from different regions of the world and classified according to their main functional feeding groups. Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12 top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decision-makers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for pot, Unión Europea, Fundación Biodiversidad (Gobierno de España), Gobierno de Navarra, Fundación para la Ciencia y la Tecnología (FECYT), FCT (Portugal), Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Studies of non-indigenous species (NIS) often tend to focus on medium and large-sized taxa with potential for remarkable ecological and/or economic impact, whereas the early detection of small invertebrates is often delayed due to taxonomic challenge, lack of consistent, standardised monitoring efforts and limited funding. This study represents the first records of the marine amphipod Laticorophium baconi (Shoemaker, 1934) in Morocco, Tunisia, Corsica (France), Italy, Greece, Egypt, Saudi Arabia and New Caledonia (France). Furthermore, it reports an expansion of its known distribution in Portugal (earliest and northernmost record for the country and first record for Macaronesia), Spain (earliest record for Atlantic and Mediterranean European waters), and Australia (first record for Indian Ocean). Recreational boating and commercial shipping, mainly through hull fouling and secondarily ballast waters, are proposed as vectors for introduction and secondary spread of L. baconi. The following traits, analysed during the present study, could contribute to its invasive potential: (i) quick and extensive spread of the species worldwide, (ii) high densities in marinas, harbours, hull fouling and other artificial habitats, including aquaculture facilities and floating debris, (iii) high ability for short-term colonisation of empty artificial niches, (iv) diet based on detritus suggesting an opportunistic feeding behaviour, and (v) population survival during seasonal fluctuations in different regions. Taxonomic expertise and scientific collaboration, based on multidisciplinary networks of experts, are crucial for the early detection, distribution updates, and risk assessment of small and overlooked stowaways in marine environments.

Aquatic ecosystems are particularly vulnerable to the introduction of non-indigenous species (NIS), leading to multi-faceted ecological, economic and health impacts worldwide. The Iberian Peninsula comprises an exceptionally biodiverse Mediterranean region with a high number of threatened and endemic aquatic species, most of them strongly impacted by biological invasions. Following a structured approach that combines a systematic review of available information and expert opinion, we provide a comprehensive and updated multi-taxa inventory of aquatic NIS (fungi, macroalgae, vascular plants, invertebrates and vertebrates) in Iberian inland waters. Moreover, we assess overall patterns in the establishment status, introduction pathways, native range and temporal introduction trends of listed NIS. In addition, we discuss the legal coverage provided by both national (Spanish and Portuguese) and European NIS regulations. We inventoried 326 aquatic NIS in Iberian inland waters, including 215 established, 96 with uncertain establishment status and 15 cryptogenic taxa. Invertebrates (54.6%) and vertebrates (24.5%) were the groups with the highest number of NIS, with Arthropoda, Mollusca, and Chordata being the most represented phyla. Recorded NIS originated from diverse geographic regions, with North and South America being the most frequent. Vertebrates and vascular plants were mostly introduced through intentional pathways (i.e. release and escape), whereas invertebrates and macroalgae arrived mostly through unintentional ways (i.e. contaminant or stowaway). Most of the recorded NIS were introduced in Iberian inland waters over the second half of the 20th century, with a high number of NIS introductions being reported in the 2000s. While only 8% of the recorded NIS appear in the European Union list of Invasive Alien Species of Union concern, around 25% are listed in the Spanish and Portuguese NIS regulations. This study provides the most updated checklist of Iberian aquati

Invasive alien species have widespread impacts on native biodiversity and ecosystem services. Since the number of introductions worldwide is continuously rising, it is essential to prevent the entry, establishment and spread of new alien species through a systematic examination of future potential threats. Applying a three-step horizon scanning consensus method, we evaluated non-established alien species that could potentially arrive, establish and cause major ecological impact in Spain within the next 10 years. Overall, we identified 47 species with a very high risk (e.g. Oreochromis niloticus, Popillia japonica, Hemidactylus frenatus, Crassula helmsii or Halophila stipulacea), 61 with high risk, 93 with moderate risk, and 732 species with low risk. Many of the species categorized as very high or high risk to Spanish biodiversity are either already present in Europe and neighbouring countries or have a long invasive history elsewhere. This study provides an updated list of potential invasive alien species useful for prioritizing efforts and resources against their introduction. Compared to previous horizon scanning exercises in Spain, the current study screens potential invaders from a wider range of terrestrial, freshwater, and marine organisms, and can serve as a basis for more comprehensive risk analyses to improve management and increase the efficiency of the early warning and rapid response framework for invasive alien species. We also stress the usefulness of measuring agreement and consistency as two different properties of the reliability of expert scores, in order to more easily elaborate consensus ranked lists of potential invasive alien species.

As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts, greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants, freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through various pathways from different regions of the world and classified according to their main functional feeding groups. Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12 top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decision-makers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for pot

As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts, greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants, freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through various pathways from different regions of the world and classified according to their main functional feeding groups. Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12 top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decision-makers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for pot

Studies of non-indigenous species (NIS) often tend to focus on medium and large-sized taxa with potential for remarkable ecological and/or economic impact, whereas the early detection of small invertebrates is often delayed due to taxonomic chal-lenge, lack of consistent, standardised monitoring efforts and limited funding. This study represents the first records of the marine amphipod Laticorophium baconi (Shoemaker, 1934) in Morocco, Tunisia, Corsica (France), Italy, Greece, Egypt, Saudi Arabia and New Caledonia (France). Furthermore, it reports an expansion of its known distribution in Portugal (earliest and northernmost record for the country and first record for Macaronesia), Spain (earliest record for Atlantic and Mediterranean European waters), and Australia (first record for Indian Ocean). Recreational boating and commercial shipping, mainly through hull fouling and sec-ondarily ballast waters, are proposed as vectors for introduction and secondary spread of L. baconi. The following traits, analysed during the present study, could contribute to its invasive potential: (i) quick and extensive spread of the species worldwide, (ii) high densities in marinas, harbours, hull fouling and other artificial habitats, including aquaculture facilities and floating debris, (iii) high ability for short-term colonisation of empty artificial niches, (iv) diet based on detritus suggesting an opportunistic feed-ing behaviour, and (v) population survival during seasonal fluctuations in different regions. Taxonomic expertise and scientific collaboration, based on multidisciplinary networks of experts, are crucial for the early detection, distribution updates, and risk assessment of small and overlooked stowaways in marine environments.

Interest in plastic contamination in inland aquatic environments due to human activity has been growing greatly. The amount of plastic produced generates severe environmental problems, due to long term deposition, but also because plastic breaks down into smaller pieces that persist and interact with aquatic biota. Many waterbirds (e.g. gulls) have shifted their natural behaviour to exploit constant anthropogenic resources (e.g. rubbish dumps) and may be biovectors of plastics and nutrients between terrestrial and aquatic environments. In south-west Spain Lesser black backed gull (Larus fuscus) and yellow legged gull (Larus michahellis) are opportunistic species exploiting resources at dumps and biovectoring plastics to natural environments (e.g. at Fuente de Piedra Lagoon and Odiel marshlands respectively) through pellet and faecal deposition. However, the role of gulls as plastic vectors has not been quantified so far. Using movement data acquired with GPS devices, combined with censuses and analysis of pellets and faeces collected from the wetlands, we quantify the amounts of plastics, other debris, and nutrients imported by gulls into these two internationally important wetlands. We consider possible management measures to reduce the extent of these biovectoring processes

One of the objectives of LIFE INVASQUA project is to develop tools that will be more efficient the Early Warning and Rapid Response (EWRR) framework for Invasive Alien Species in the Iberian Peninsula. Horizon scanning for high-risk IAS is basic in implementing measures to reduce new invasions, developing Alert lists, and to focus effort in the species already established, for instance making a Black list. We developed a trans national horizon scanning exercise focused on inland waters of Spain and Portugal in order to provide a prioritized lists (Black list and Alert list) of aquatic IAS that may pose a threat to aquatic ecosystems and socio economic sectors in the future. We followed a step approach of existing information about IAS (Plants, Freshwater Invertebrates, Estuarine Invertebrates and Vertebrates; 127 established taxa in Black list; 90 non established taxa in Alert list) combining with an expert scoring of prioritized taxa. IAS established in the Iberian aquatic system consistently highlighted as the worst included vertebrates (e.g. Cyprinus carpio, Gambusia holbrooki, Silurus glanis), freshwater and estuarine invertebrates (e.g. Procambarus clarkii, Dreissena polymorpha, Pacifastacus leniusculus, Ficopomatus enigmaticus, Callinectes sapidus, Corbicula fluminea) and plants (e.g. Eichhornia crassipes, Azolla filiculoides, Ludwigia grandiflora). Amongst taxa not yet established (Alert list), expert pointed to Perna viridis, Hydroides dirampha, Dreissena bugensis, Procambarus fallax f. virginallis, Perccottus glenii with higher risk of invasion, ecological and socioeconomic impacts. Over 20.6% of the taxa in the preliminary black list received no votes (no prioritization) by experts, 17.8% in the innitial alert list. Our horizon scanning approach is inclusive of all-taxa, prioritizes both established and emerging biological threats across trans-national scales, and considers not only the ecological impact, but also potential direct economic consequences as

The role of ecophysiology in mediating marine biological pollution is poorly known. Here we explore how physiological plasticity to environmental stress can explain and predict the context-dependencies of invasive species impacts. We use the case of two sympatric skeleton shrimps, the invader Caprella scaura and its congener C. equilibra, which is currently replaced by the former on the South European coast. We compare their physiological responses to hyposalinity stress under suboptimal low and high temperature, while inferring on hypoxia tolerance. We use an energy-redox approach, analyzing mortality rate, the energetic balance and the consequent effects on the oxidative homeostasis. We found that decreased seawater salinity and/or oxygen levels can weaken biotic resistance, especially in females of C. equilibra, leading to periods of heightened vulnerability to invasion. Our approach provides mechanistic insights towards understanding the factors promoting invader impacts, highlighting the potential of ecophysiology for improving invasive species management.

The role of ecophysiology in mediating marine biological pollution is poorly known. Here we explore how physiological plasticity to environmental stress can explain and predict the context-dependencies of invasive species impacts. We use the case of two sympatric skeleton shrimps, the invader Caprella scaura and its congener C. equilibra, which is currently replaced by the former on the South European coast. We compare their physiological responses to hyposalinity stress under suboptimal low and high temperature, while inferring on hypoxia tolerance. We use an energy-redox approach, analyzing mortality rate, the energetic balance and the consequent effects on the oxidative homeostasis. We found that decreased seawater salinity and/or oxygen levels can weaken biotic resistance, especially in females of C. equilibra, leading to periods of heightened vulnerability to invasion. Our approach provides mechanistic insights towards understanding the factors promoting invader impacts, highlighting the potential of ecophysiology for improving invasive species management.

The role of ecophysiology in mediating marine biological pollution is poorly known. Here we explore how physiological plasticity to environmental stress can explain and predict the context-dependencies of invasive species impacts. We use the case of two sympatric skeleton shrimps, the invader Caprella scaura and its congener C. equilibra, which is currently replaced by the former on the South European coast. We compare their physiological responses to hyposalinity stress under suboptimal low and high temperature, while inferring on hypoxia tolerance. We use an energy-redox approach, analyzing mortality rate, the energetic balance and the consequent effects on the oxidative homeostasis. We found that decreased seawater salinity and/or oxygen levels can weaken biotic resistance, especially in females of C. equilibra, leading to periods of heightened vulnerability to invasion. Our approach provides mechanistic insights towards understanding the factors promoting invader impacts, highlighting the potential of ecophysiology for improving invasive species management.

The role of ecophysiology in mediating marine biological pollution is poorly known. Here we explore how physiological plasticity to environmental stress can explain and predict the context-dependencies of invasive species impacts. We use the case of two sympatric skeleton shrimps, the invader Caprella scaura and its congener C. equilibra, which is currently replaced by the former on the South European coast. We compare their physiological responses to hyposalinity stress under suboptimal low and high temperature, while inferring on hypoxia tolerance. We use an energy-redox approach, analyzing mortality rate, the energetic balance and the consequent effects on the oxidative homeostasis. We found that decreased seawater salinity and/or oxygen levels can weaken biotic resistance, especially in females of C. equilibra, leading to periods of heightened vulnerability to invasion. Our approach provides mechanistic insights towards understanding the factors promoting invader impacts, highlighting the potential of ecophysiology for improving invasive species management.

The importance of marinas as infrastructures for recreational boating is increasing substantially. However, information on their soft-bottom benthic communities, a key tool for managing programmes, is still scarce. We combined environment features with macro- and meiofaunal soft-bottom community information for assessing the ecological status of marinas with an integrative approach. To address this issue, we focused on eight marinas of the Southern Iberian Peninsula. Macro- and meiofauna data revealed high benthic heterogeneity at a spatial scale. The environmental variables which correlated best with macrofauna were mainly phosphorus, granulometry, and total organic carbon, and secondarily important variables were faecal coliforms, the biocide Irgarol, and heavy metals; total hydrocarbon concentration was also significant for meiofauna. Annelida was the dominant phylum in terms of number of species (37%) and abundance (66%) and were better descriptors of the environmental conditions than Arthropoda and Mollusca. Although identification to the species level is desirable and mandatory for assessing biological pollution, significant differences among marinas and correlations between fauna and abiotic variables were already detected at the level of family and order. This implies that biota assessment at higher levels may still be useful in monitoring programmes limited by time and budget constraints. The major novelty of this study lies in the development of an integrative assessment method based on the following selected ecological indicators: Marinas Environmental Pollution Index (MEPI), Biocontamination Index (BCI), macrofaunal biotic indices (AMBI, M-AMBI, BENTIX, MEDOCC and BENFES), macrofaunal taxa richness and Shannon-Wiener's diversity, and nematode:copepod index. This approach was able to discriminate marinas of the Southern Iberian Peninsula based on their ecological status, which ranged from poor to good. The method can be useful to design standards for assi

Detection of new non-indigenous species is often delayed when taxa are taxonomically challenging, such as small-sized marine organisms. The present study highlights the relevance of scientific cooperation in the early detection of the invader amphipod Stenothoe georgiana. Originally described from North Carolina (USA), the species was recently found in Chile and the Western Mediterranean. Here, we provide the first record of the species in Macaronesia, Atlantic coasts of continental Europe, North Africa and Australia, and extend its known distribution along the Mediterranean coast. Just like other small crustaceans, shipping (both ballast water and recreational boating) and aquaculture are probably the main vectors of introduction and secondary spread for this amphipod species. This case of S. georgiana sheds light on the importance of promoting taxonomical knowledge, and building multidisciplinary networks of experts that ensure an effective diessemination of alien species information. We also encourage the implementation of standardized monitoring methodologies to facilitate early detection of small mobile invaders.

Detection of new non-indigenous species is often delayed when taxa are taxonomically challenging, such as small-sized marine organisms. The present study highlights the relevance of scientific cooperation in the early detection of the invader amphipod Stenothoe georgiana. Originally described from North Carolina (USA), the species was recently found in Chile and the Western Mediterranean. Here, we provide the first record of the species in Macaronesia, Atlantic coasts of continental Europe, North Africa and Australia, and extend its known distribution along the Mediterranean coast. Just like other small crustaceans, shipping (both ballast water and recreational boating) and aquaculture are probably the main vectors of introduction and secondary spread for this amphipod species. This case of S. georgiana sheds light on the importance of promoting taxonomical knowledge, and building multidisciplinary networks of experts that ensure an effective diessemination of alien species information. We also encourage the implementation of standardized monitoring methodologies to facilitate early detection of small mobile invaders.

Se presenta una lista actualizada de las especies exóticas que se encuentran en etapa de establecimiento o de propagación de la invasión en aguas continentales de la península ibérica. La lista está basada en la evaluación sistemática de los datos en colaboración con un amplio equipo de expertos de España y Portugal. Esta lista de actualización es un instrumento de apoyo importante para la aplicación del Reglamento de la Unión Europea (UE) sobre las especies exóticas invasoras (EEI) y también proporciona una base objetiva para el examen de su aplicación. En última instancia, la información incluida puede utilizarse para supervisar el cumplimiento del objetivo de la Estrategia de la UE sobre diversidad biológica hasta 2030 para combatir las EEI, pero también para la aplicación de otras políticas de la UE con requisitos sobre especies exóticas, como las Directivas de Hábitats y Aves, la Directiva Marco sobre la Estrategia Marina (DMEM) y la Directiva Marco del Agua (DMA). Esta publicación es un informe técnico del Proyecto Europeo LIFE INVASAQUA (LIFE17 GIE/ES/000515). Ha sido redactado por un equipo de expertos en el marco del proyecto y tiene por objeto proporcionar apoyo, basado en pruebas científicas, al proceso de formulación de políticas europeas. La información científica aportada no implica una posición política de la Comisión Europea. Ni la Comisión Europea ni ninguna persona que actúe en nombre de la Comisión es responsable del uso que pueda hacerse de esta publicación.

Paracaprella pusilla Mayer, 1890 is a tropical caprellid species recently introduced to the Eastern Atlantic coast of the Iberian Peninsula and the Mediterranean Sea. In this study, we used direct sequencing of mitochondrial (COI and 16S) and nuclear (28S and ITS) genes to compare genetic differences in presumed native and introduced populations in order to infer its introduction pattern and to shed light on the native range of this species. The temporal pattern of genetic diversity at the westernmost limit of the geographic range of P. pusilla in Europe (the Atlantic coast of southern Spain) over an eight-year period was also investigated. Our results confirm P. pusilla as a neocosmopolitan species and suggest that the species is native to the Atlantic coast of Central and South America. Paracaprella pusilla seems to have been introduced into European waters from multiple introduction pathways and source populations, which are likely to include populations from coastal waters of Brazil. Multiple introduction pathways may have been involved, with the most important being commercial shipping through the Strait of Gibraltar. While this tropical species appears to be expanding in the Mediterranean, populations from the westernmost limit of its geographic range in Europe showed a temporal instability. This study constitutes the first molecular approach focused on this species, but it is also the first study of temporal change in genetic diversity of any introduced marine amphipod. Additional intensive sampling of this species, including both native and non-native populations, and detailed temporal studies are still necessary to properly understand how genetic diversity influences the introduction and survival of P. pusilla in invaded areas.

Paracaprella pusilla Mayer, 1890 is a tropical caprellid species recently introduced to the Eastern Atlantic coast of the Iberian Peninsula and the Mediterranean Sea. In this study, we used direct sequencing of mitochondrial (COI and 16S) and nuclear (28S and ITS) genes to compare genetic differences in presumed native and introduced populations in order to infer its introduction pattern and to shed light on the native range of this species. The temporal pattern of genetic diversity at the westernmost limit of the geographic range of P. pusilla in Europe (the Atlantic coast of southern Spain) over an eight-year period was also investigated. Our results confirm P. pusilla as a neocosmopolitan species and suggest that the species is native to the Atlantic coast of Central and South America. Paracaprella pusilla seems to have been introduced into European waters from multiple introduction pathways and source populations, which are likely to include populations from coastal waters of Brazil. Multiple introduction pathways may have been involved, with the most important being commercial shipping through the Strait of Gibraltar. While this tropical species appears to be expanding in the Mediterranean, populations from the westernmost limit of its geographic range in Europe showed a temporal instability. This study constitutes the first molecular approach focused on this species, but it is also the first study of temporal change in genetic diversity of any introduced marine amphipod. Additional intensive sampling of this species, including both native and non-native populations, and detailed temporal studies are still necessary to properly understand how genetic diversity influences the introduction and survival of P. pusilla in invaded areas.

Paracaprella pusilla Mayer, 1890 is a tropical caprellid species recently introduced to the Eastern Atlantic coast of the Iberian Peninsula and the Mediterranean Sea. In this study, we used direct sequencing of mitochondrial (COI and 16S) and nuclear (28S and ITS) genes to compare genetic differences in presumed native and introduced populations in order to infer its introduction pattern and to shed light on the native range of this species. The temporal pattern of genetic diversity at the westernmost limit of the geographic range of P. pusilla in Europe (the Atlantic coast of southern Spain) over an eight-year period was also investigated. Our results confirm P. pusilla as a neocosmopolitan species and suggest that the species is native to the Atlantic coast of Central and South America. Paracaprella pusilla seems to have been introduced into European waters from multiple introduction pathways and source populations, which are likely to include populations from coastal waters of Brazil. Multiple introduction pathways may have been involved, with the most important being commercial shipping through the Strait of Gibraltar. While this tropical species appears to be expanding in the Mediterranean, populations from the westernmost limit of its geographic range in Europe showed a temporal instability. This study constitutes the first molecular approach focused on this species, but it is also the first study of temporal change in genetic diversity of any introduced marine amphipod. Additional intensive sampling of this species, including both native and non-native populations, and detailed temporal studies are still necessary to properly understand how genetic diversity influences the introduction and survival of P. pusilla in invaded areas.

Paracaprella pusilla Mayer, 1890 is a tropical caprellid species recently introduced to the Eastern Atlantic coast of the Iberian Peninsula and the Mediterranean Sea. In this study, we used direct sequencing of mitochondrial (COI and 16S) and nuclear (28S and ITS) genes to compare genetic differences in presumed native and introduced populations in order to infer its introduction pattern and to shed light on the native range of this species. The temporal pattern of genetic diversity at the westernmost limit of the geographic range of P. pusilla in Europe (the Atlantic coast of southern Spain) over an eight-year period was also investigated. Our results confirm P. pusilla as a neocosmopolitan species and suggest that the species is native to the Atlantic coast of Central and South America. Paracaprella pusilla seems to have been introduced into European waters from multiple introduction pathways and source populations, which are likely to include populations from coastal waters of Brazil. Multiple introduction pathways may have been involved, with the most important being commercial shipping through the Strait of Gibraltar. While this tropical species appears to be expanding in the Mediterranean, populations from the westernmost limit of its geographic range in Europe showed a temporal instability. This study constitutes the first molecular approach focused on this species, but it is also the first study of temporal change in genetic diversity of any introduced marine amphipod. Additional intensive sampling of this species, including both native and non-native populations, and detailed temporal studies are still necessary to properly understand how genetic diversity influences the introduction and survival of P. pusilla in invaded areas.

Paracaprella pusilla Mayer, 1890 is a tropical caprellid species recently introduced to the Eastern Atlantic coast of the Iberian Peninsula and the Mediterranean Sea. In this study, we used direct sequencing of mitochondrial (COI and 16S) and nuclear (28S and ITS) genes to compare genetic differences in presumed native and introduced populations in order to infer its introduction pattern and to shed light on the native range of this species. The temporal pattern of genetic diversity at the westernmost limit of the geographic range of P. pusilla in Europe (the Atlantic coast of southern Spain) over an eight-year period was also investigated. Our results confirm P. pusilla as a neocosmopolitan species and suggest that the species is native to the Atlantic coast of Central and South America. Paracaprella pusilla seems to have been introduced into European waters from multiple introduction pathways and source populations, which are likely to include populations from coastal waters of Brazil. Multiple introduction pathways may have been involved, with the most important being commercial shipping through the Strait of Gibraltar. While this tropical species appears to be expanding in the Mediterranean, populations from the westernmost limit of its geographic range in Europe showed a temporal instability. This study constitutes the first molecular approach focused on this species, but it is also the first study of temporal change in genetic diversity of any introduced marine amphipod. Additional intensive sampling of this species, including both native and non-native populations, and detailed temporal studies are still necessary to properly understand how genetic diversity influences the introduction and survival of P. pusilla in invaded areas.

Paracaprella pusilla Mayer, 1890 is a tropical caprellid species recently introduced to the Eastern Atlantic coast of the Iberian Peninsula and the Mediterranean Sea. In this study, we used direct sequencing of mitochondrial (COI and 16S) and nuclear (28S and ITS) genes to compare genetic differences in presumed native and introduced populations in order to infer its introduction pattern and to shed light on the native range of this species. The temporal pattern of genetic diversity at the westernmost limit of the geographic range of P. pusilla in Europe (the Atlantic coast of southern Spain) over an eight-year period was also investigated. Our results confirm P. pusilla as a neocosmopolitan species and suggest that the species is native to the Atlantic coast of Central and South America. Paracaprella pusilla seems to have been introduced into European waters from multiple introduction pathways and source populations, which are likely to include populations from coastal waters of Brazil. Multiple introduction pathways may have been involved, with the most important being commercial shipping through the Strait of Gibraltar. While this tropical species appears to be expanding in the Mediterranean, populations from the westernmost limit of its geographic range in Europe showed a temporal instability. This study constitutes the first molecular approach focused on this species, but it is also the first study of temporal change in genetic diversity of any introduced marine amphipod. Additional intensive sampling of this species, including both native and non-native populations, and detailed temporal studies are still necessary to properly understand how genetic diversity influences the introduction and survival of P. pusilla in invaded areas.

The search for alternative live feed organisms and the progression of Integrative Multi-Trophic Aquaculture (IMTA) are currently being highly prioritised in EU strategies. Caprellids could potentially be an important exploitable resource in aquaculture due to their high levels of beneficial polyunsaturated fatty acids, fast growing nature and widespread distribution. Furthermore, since they are mainly detritivorous, they could be excellent candidates for integration into IMTA systems, potentially benefitting from uneaten feed pellets and faeces released by cultured fish in fish farms and sea-cage structures. Despite this, there is a lack of experimental studies to: (i) test inexpensive diets for caprellids, such as detritus, (ii) develop sustainable caprellid culture techniques and (iii) include caprellids in IMTA systems. The main aim of this study was to determine whether detritus (D) in the form of fish faeces provided an adequate diet for caprellids in comparison to other traditional diets, such as Artemia nauplii (A) or phytoplankton (P). Adult survival rate was shown to be significantly higher for caprellids fed with D. Conversely, hatchlings had the highest survival rate with A, although the juvenile growth rate and number of moults was similar in the three diets. With regard to lipid composition, caprellids fed with A had higher concentrations of Triacylglycerols (TAG) and Phosphatidylcholine (PC) while those fed with P or D were richer in polyunsaturated fatty acids, especially 22:6(n-3) (DHA). Interestingly, caprellids fed with D were also a rich source of 18:2(n-6) (LA), considered to be an essential fatty acid in vertebrates. It was found that detritus based mainly on fish faeces and uneaten feed pellets can be considered an adequate feed for adult caprellids, providing a source of both omega-3 (DHA) and omega-6 (LA) fatty acids. Hatchlings however seem to require an additional input of TAG and PC during juvenile stages to properly grow.

In spite of the high importance of mobile epifauna in all marine habitats, their pat terns of colonization and succession in marine caves have not been studied until now. In the pres ent study, we used artificial substrates deployed at 4 positions along an environmental gradient of a ~100 m long cave system, and retrieved at different times (1.5, 3 and 6 mo), to explore the changes in abundance, species richness, and community structure of the epifauna. All inner cave stations showed significantly lower species richness and abundance. Despite different dispersal modes, the dominant species detected were able to quickly (<1.5 mo) colonize the inner parts of the cave, yet their abundances were significantly higher outside the cave throughout the whole study. This suggests that environmental factors such as trophic supply or light intensity, rather than isolation, are probably the main factors responsible for the observed differences among cave positions. We also detected a gradient in the rate of community development, with communities outside the cave developing much earlier than those situated in the innermost parts. Finally, high temporal stability of communities was observed within the cave, which is likely related to more stable environmental conditions — a hypothesis supported by our detection of a dampening of the thermal oscillations within the cave. The low rates of community development and turnover observed inside marine caves supports the consideration of these habitats being very sensitive to natural and human-induced environmental disturbances, and hence a top priority for conservation

In spite of the high importance of mobile epifauna in all marine habitats, their pat terns of colonization and succession in marine caves have not been studied until now. In the pres ent study, we used artificial substrates deployed at 4 positions along an environmental gradient of a ~100 m long cave system, and retrieved at different times (1.5, 3 and 6 mo), to explore the changes in abundance, species richness, and community structure of the epifauna. All inner cave stations showed significantly lower species richness and abundance. Despite different dispersal modes, the dominant species detected were able to quickly (<1.5 mo) colonize the inner parts of the cave, yet their abundances were significantly higher outside the cave throughout the whole study. This suggests that environmental factors such as trophic supply or light intensity, rather than isolation, are probably the main factors responsible for the observed differences among cave positions. We also detected a gradient in the rate of community development, with communities outside the cave developing much earlier than those situated in the innermost parts. Finally, high temporal stability of communities was observed within the cave, which is likely related to more stable environmental conditions — a hypothesis supported by our detection of a dampening of the thermal oscillations within the cave. The low rates of community development and turnover observed inside marine caves supports the consideration of these habitats being very sensitive to natural and human-induced environmental disturbances, and hence a top priority for conservation

In spite of the high importance of mobile epifauna in all marine habitats, their pat terns of colonization and succession in marine caves have not been studied until now. In the pres ent study, we used artificial substrates deployed at 4 positions along an environmental gradient of a ~100 m long cave system, and retrieved at different times (1.5, 3 and 6 mo), to explore the changes in abundance, species richness, and community structure of the epifauna. All inner cave stations showed significantly lower species richness and abundance. Despite different dispersal modes, the dominant species detected were able to quickly (<1.5 mo) colonize the inner parts of the cave, yet their abundances were significantly higher outside the cave throughout the whole study. This suggests that environmental factors such as trophic supply or light intensity, rather than isolation, are probably the main factors responsible for the observed differences among cave positions. We also detected a gradient in the rate of community development, with communities outside the cave developing much earlier than those situated in the innermost parts. Finally, high temporal stability of communities was observed within the cave, which is likely related to more stable environmental conditions — a hypothesis supported by our detection of a dampening of the thermal oscillations within the cave. The low rates of community development and turnover observed inside marine caves supports the consideration of these habitats being very sensitive to natural and human-induced environmental disturbances, and hence a top priority for conservation

In spite of the high importance of mobile epifauna in all marine habitats, their pat terns of colonization and succession in marine caves have not been studied until now. In the pres ent study, we used artificial substrates deployed at 4 positions along an environmental gradient of a ~100 m long cave system, and retrieved at different times (1.5, 3 and 6 mo), to explore the changes in abundance, species richness, and community structure of the epifauna. All inner cave stations showed significantly lower species richness and abundance. Despite different dispersal modes, the dominant species detected were able to quickly (<1.5 mo) colonize the inner parts of the cave, yet their abundances were significantly higher outside the cave throughout the whole study. This suggests that environmental factors such as trophic supply or light intensity, rather than isolation, are probably the main factors responsible for the observed differences among cave positions. We also detected a gradient in the rate of community development, with communities outside the cave developing much earlier than those situated in the innermost parts. Finally, high temporal stability of communities was observed within the cave, which is likely related to more stable environmental conditions — a hypothesis supported by our detection of a dampening of the thermal oscillations within the cave. The low rates of community development and turnover observed inside marine caves supports the consideration of these habitats being very sensitive to natural and human-induced environmental disturbances, and hence a top priority for conservation

In spite of the high importance of mobile epifauna in all marine habitats, their pat terns of colonization and succession in marine caves have not been studied until now. In the pres ent study, we used artificial substrates deployed at 4 positions along an environmental gradient of a ~100 m long cave system, and retrieved at different times (1.5, 3 and 6 mo), to explore the changes in abundance, species richness, and community structure of the epifauna. All inner cave stations showed significantly lower species richness and abundance. Despite different dispersal modes, the dominant species detected were able to quickly (<1.5 mo) colonize the inner parts of the cave, yet their abundances were significantly higher outside the cave throughout the whole study. This suggests that environmental factors such as trophic supply or light intensity, rather than isolation, are probably the main factors responsible for the observed differences among cave positions. We also detected a gradient in the rate of community development, with communities outside the cave developing much earlier than those situated in the innermost parts. Finally, high temporal stability of communities was observed within the cave, which is likely related to more stable environmental conditions — a hypothesis supported by our detection of a dampening of the thermal oscillations within the cave. The low rates of community development and turnover observed inside marine caves supports the consideration of these habitats being very sensitive to natural and human-induced environmental disturbances, and hence a top priority for conservation

In spite of the high importance of mobile epifauna in all marine habitats, their pat terns of colonization and succession in marine caves have not been studied until now. In the pres ent study, we used artificial substrates deployed at 4 positions along an environmental gradient of a ~100 m long cave system, and retrieved at different times (1.5, 3 and 6 mo), to explore the changes in abundance, species richness, and community structure of the epifauna. All inner cave stations showed significantly lower species richness and abundance. Despite different dispersal modes, the dominant species detected were able to quickly (<1.5 mo) colonize the inner parts of the cave, yet their abundances were significantly higher outside the cave throughout the whole study. This suggests that environmental factors such as trophic supply or light intensity, rather than isolation, are probably the main factors responsible for the observed differences among cave positions. We also detected a gradient in the rate of community development, with communities outside the cave developing much earlier than those situated in the innermost parts. Finally, high temporal stability of communities was observed within the cave, which is likely related to more stable environmental conditions — a hypothesis supported by our detection of a dampening of the thermal oscillations within the cave. The low rates of community development and turnover observed inside marine caves supports the consideration of these habitats being very sensitive to natural and human-induced environmental disturbances, and hence a top priority for conservation

In spite of the high importance of mobile epifauna in all marine habitats, their pat terns of colonization and succession in marine caves have not been studied until now. In the pres ent study, we used artificial substrates deployed at 4 positions along an environmental gradient of a ~100 m long cave system, and retrieved at different times (1.5, 3 and 6 mo), to explore the changes in abundance, species richness, and community structure of the epifauna. All inner cave stations showed significantly lower species richness and abundance. Despite different dispersal modes, the dominant species detected were able to quickly (<1.5 mo) colonize the inner parts of the cave, yet their abundances were significantly higher outside the cave throughout the whole study. This suggests that environmental factors such as trophic supply or light intensity, rather than isolation, are probably the main factors responsible for the observed differences among cave positions. We also detected a gradient in the rate of community development, with communities outside the cave developing much earlier than those situated in the innermost parts. Finally, high temporal stability of communities was observed within the cave, which is likely related to more stable environmental conditions — a hypothesis supported by our detection of a dampening of the thermal oscillations within the cave. The low rates of community development and turnover observed inside marine caves supports the consideration of these habitats being very sensitive to natural and human-induced environmental disturbances, and hence a top priority for conservation