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This work reports on 60 marine alien mollusks from nine countries across the Mediterranean Sea and the Sea of Marmara collected by two Belgian citizen scientists. Some of their published observations concerning collection dates are compared with the year of first publication for these alien mollusks reported in the literature, which enable us to backdate some of their introductions and set new first Mediterranean records for two species. This underlines the importance of collaboration between volunteers and institutional scientists in tracing variations and changes in the environment and biodiversity. [ABSTRACT FROM AUTHOR]

The arrival of a new invasive alga, Rugulopteryx okamurae, in the Strait of Gibraltar (SoG) in 2015 marked an unprecedented milestone in the North African and, later, in the European marine ecosystems. Nowadays, it is colonising vast infralittoral areas and significantly modifying some habitats and associated communities of the southern Iberian Peninsula. In recent expeditions, a high amount of free drifted thalli of this alga has been detected in different circalittoral and bathyal habitats of the northern SoG and the Alboran Sea. The present study combines quantitative data of this alga obtained with the use of a remotely operated vehicle (ROV) and a bottom otter trawl. The coverage–entanglement level of the drifted thalli on circalittoral and bathyal benthic invertebrates (e.g., not covering, covering only the basal part, covering one-third of the invertebrate, etc.) was also annotated from picture frames taken in locations with abundant drifted thalli. In underwater images, drifted thalli were mainly detected in circalittoral and bathyal bottoms of the northern SoG and the north-western Alboran Sea, between 50 to ca. 450 m depth. Nevertheless, abundant drifted thalli were also detected in bottom otter trawl samples from circalittoral bottoms of the north-central and north-eastern Alboran Sea. Small benthic organisms (e.g., encrusting sponges, hydrozoans, etc.) generally displayed low coverage–entanglement levels of drifted thalli. Nevertheless, large sessile and colonial benthic organisms with a complex three-dimensional morphology (e.g., gorgonians, colonial scleractinians) reached high levels of R. okamurae thalli entangled in different parts of their colonies. The drifted R. okamurae thalli entangled in these colonial suspension feeding organisms may hinder their feeding capability in the long term, resulting in habitat deterioration in the near future. [ABSTRACT FROM AUTHOR]

The current study provides new data on the known records of the Atlantic blue crab, Callinectes sapidus Rathbun, 1896, from the Maltese Islands through two ovigerous female specimens collected from Salini (Malta), a Natura 2000 site, in August 2020. Additional new records of the species were also presented from the San Leonardo River estuary, Syracuse (Sicily, Italy), in August 2022. The specimens collected from both Malta and Sicily were identified using both morphological and molecular analyses. The latter has shown that all the specimens analysed share their mitochondrial DNA barcode region with the most recorded haplotype of the same species from the Mediterranean Sea. Knowing the new distribution and range expansion records of alien species is important for the continuous monitoring of marine alien species, which is essential for the implementation of the best possible mitigation measures. This is especially relevant for C. sapidus, as it is considered one of the worst invaders of the Mediterranean Sea. Therefore, given that this alien species is edible, fishing for it may allow some control over its population size and further expansion. Knowing its distribution is crucial to inform fishers about its exact location, making such a mitigation measure more effective. [ABSTRACT FROM AUTHOR]

The introduction of new non-indigenous species (NIS) in Spanish marine waters is addressed under Descriptor 2 of the European Union's Marine Strategy Framework Directive. National baseline inventories of NIS have been compiled and updated for the three subregions (Western Mediterranean Sea, WMED; Bay of Biscay–Iberian Coast, ABI; Macaronesia, AMA) with data from 1800 to 2021. An overall of 574 species were identified with an alien, cryptogenic, crypto-expanding, or debatable status, mostly invertebrates (~65%) and primary producers (~22%). Of 412 alien species, 80.51% were reported in ABI, 67.82% in WMED, and 66.67% in AMA. Cryptogenic species are more abundant in the WMED (25.25%), compared to AMA (19.77%) and ABI (18.46%). ABI harbors more established species (62.56%) than AMA (45.2%) and WMED (43.56%), contrary to casual records (AMA 31.64%, WMED 23.76%, ABI 13.85%). Invasive species are more abundant (14.36%) in WMED. The 'transport-stowaway' pathway accounted for 142 (79.33%), 123 (67.58%), and 169 (85.21%) records in WMED, ABI, and AMA, respectively. The second most common pathway was 'transport-contaminant' related to mariculture (~10% of the total), prevalently in ABI with 42 species (23.08%). The Canary Islands stand out for species introduced through oil platforms from throughout the world. 'Unaided' was a relevant pathway of secondary introduction into the WMED, particularly of Lessepsian species progressing westwards. Temporal trends in newly introduced species show similar behavior among subregions. [ABSTRACT FROM AUTHOR]

Following disturbances, ecosystems are more susceptible to invasion by non-native species. Furthermore, it is important to determine the impact of alien tree species on soil regeneration processes during secondary succession. In this study, we analyzed the effect of native and late successional common oak (Quercus robur) and non-native red oak (Q. rubra) on soil physicochemical (pH, carbon, and nutrient content) and microbial properties (microbial biomass [Cmic] and respiration [RESP]) nearly 30 years after severe fire disturbance. Post-fire soils under Q. rubra had organic horizons with a greater mass, lower pH values, and depleted nutrient (N, Ca, K, Mg, and P) contents than soils under Q. robur. The impact of Q. robur as a late successional species on soil properties 30 years after a disturbance was similar to that of pioneer species (Scots pine, European larch, common birch, and black alder), as is indicated in previous studies. Most of the studied physicochemical (bulk density, soil organic carbon, N, Ca, K, and P content) and microbial (RESP and Cmic) soil parameters under Q. robur were within the ranges found for post-fire soils under pioneer tree species. Only the pH and Mg and Na contents in organic horizons were higher under Q. robur than under pioneer species. Our results indicate that Q. robur could be a valuable addition to reforestation sites after fire disturbance, especially in more fertile microhabitats. Due to the depletion of soil nutrients, care should be taken when introducing Q. rubra during the reforestation of post-fire sites, especially in larger groups. [ABSTRACT FROM AUTHOR]

Invasive "game-changer" species cause severe ecological impacts such as "phase shifts" in recipient ecosystems all over the world. Since the early 1990s, the ongoing global spread of the small but highly invasive Ponto-Caspian round goby Neogobius melanostomus into diverse freshwater and marine ecosystems has been observed. We postulate that this species is an ideal model to better understand and mitigate aquatic invasions. Its wide invaded range, as well as its diverse impacts on native species, have triggered a large body of research worldwide concerning its spread, ecology, and traits facilitating invasion. Several hypotheses related to invasiveness have been tested for the round goby, which are also applicable to other invasive species and for understanding general principles in invasion biology. However, a common theory explaining invasion success, especially in round goby, is still lacking. Many case studies do not consider time since invasion and use different sampling protocols and methodologies, hampering the comparability of results and conclusions. We thus propose strengthening the network of goby researchers and establishing long-term databases based on continuous and harmonized monitoring covering all stages of the invasion process as crucial requirements to better understand and manage aquatic invasions. In many cases, such monitoring can easily be integrated into existing survey schemes. [ABSTRACT FROM AUTHOR]

The diversity of biota in different parts of the planet has demonstrated dramatic changes within the last several decades due to the extinction of native taxa and the appearance of invasive taxa. The correct taxonomic identification of non-native species is important for understanding their dispersal abilities, especially when potential invaders may be of closely related species. Information on the species identity of ricefish (Oryzias spp.), which have formed self-sustainable populations in some parts of Eurasia, is contradictory. In this paper, we studied samples from non-native populations of Oryzias from several Eurasian regions. The results of our mtDNA COI partial sequence study confirm that the individuals we studied belong to the species Chinese ricefish, O. sinensis. Analyses of the literature and our own data suggest that all known alien populations of Oryzias in continental Eurasia belong to the same species, O. sinensis. A recent finding of O. sinensis in the Don delta suggests that one of the species' secondary dispersal pathways could run from the Kuban region through the lower part of the Don basin to the Cis-Azov area. [ABSTRACT FROM AUTHOR]

To promote sustainability in urban green spaces, it is necessary to know the diversity of spontaneous species in these spaces. Based on the investigation and analysis of the relevant scientific literature, the diversity of spontaneous species and their importance was contextually discussed, along with the assessment of local biodiversity impact in green spaces. Studies on green spaces, spontaneous flora, biodiversity or ecosystem services, and studies on exotic species and adaptability were summarized. Finally, the existing issues regarding biodiversity and urbanization, and the role of spontaneous plants in restoring industrial areas were discussed. Based on the research carried out, it is considered that green spaces contain unique and useful biodiversity resulting from their management. Spontaneous flora can be a generator of plants with aesthetic character, which can be grown in an ecologically sound way in private gardens and natural spaces in town and village zones, with certain remarkable farming-biological characteristics (ecological plasticity, high hardiness, etc.). Biodiversity is a relevant feature of urban landscapes, offering multiple gains, and the conservation of this biodiversity in urban green spaces is fundamental and requires an integrated approach. However, urbanisation usually has a detrimental influence on local species' diversity. [ABSTRACT FROM AUTHOR]

A critical review of marine fishes from Malta (Central Mediterranean) recorded up to December 2022 in the technical and semi-popular literature, during the Mediterranean International Trawl Survey (MEDITS), and in commercial fisheries landings data, was undertaken with the main aim of producing a checklist of species whose occurrence in the seas around the Maltese Islands could be authenticated. This review also served to generate two other lists: one of the species whose occurrence around the islands is probable or possible but which require confirmation, and a second list of previously reported species whose occurrence was deemed highly unlikely and which were hence excluded; the reasons for such exclusion are given. A total of 412 species were confirmed as occurring in Maltese waters, 53 species were listed as requiring confirmation, and 78 species were excluded. Of the species whose occurrence around the Maltese Islands was confirmed, 370 were native; 17 were non-established aliens; seven were established aliens; three were non-established Atlantic immigrants; five were established Atlantic immigrants; nine were non-established cryptogenic; and one was an established cryptogenic. The 412 confirmed species from the Maltese Islands represent 54% of the Mediterranean fish species that have been recorded in recently published works. Therefore, considering the geographical location of the islands at the centre of the Mediterranean, they provide a presumed ideal siting for a good representation of the marine ichthyological fauna. The Maltese checklist appears to still be short of many fish species that probably occur locally and have yet to be added to the present confirmed list. Nevertheless, the present review serves as a good indication of the current situation of the Maltese fish fauna, also noting that checklists for the group from neighbouring countries are somewhat outdated and require review and updating. [ABSTRACT FROM AUTHOR]

In the modern world, when the problems of the environment are most acutely associated with climate change, amphibians are considered to be the most vulnerable group of anamniotes as an indicator of the state of wetlands. Along with a decrease of numbers among amphibians in Europe, nowadays newts especially suffer from the impact of invasive species, in particular predators such as the Chinese sleeper, Perccottus glenii. This predatory fish species has recently spread to areas of primary relevance for newt reproduction. This fish consumes eggs, larvae, and even adult newt individuals. Using an ecological niche approach and climate based species distribution models (SDM), we applied the coefficient of determination (R2) for comparing the level of similarity of the built SDM for the newts Triturus cristatus and Lissotriton vulgaris, and the Chinese sleeper. We show that by 2050, the level of climatic niche similarity for these native and invasive species will increase from 12% to 22% throughout Europe, and from 44% to 66% in Eastern Europe. This study highlights the expansion of the Chinese sleeper as a real threat to European biodiversity of wetlands in the near future, especially in their most northeastern distribution range. [ABSTRACT FROM AUTHOR]

This work presents currently available knowledge on alien species (AS) found in the inland waters of Morocco. The objective is to provide an updated list of alien species and identify the main introduction pathways and possible threats to native biodiversity. The dataset was built from an extensive literature search supplemented by our own research work (published or in progress). The main areas harboring xenodiversity in Moroccan freshwaters correspond to protected areas (e.g., Ramsar Site and SIBE). These areas are currently home to 41 confirmed AS belonging to different taxonomic groups. Fish are the most abundant taxonomic group with 21 species, followed by molluscs (7 species) and arthropods (7 species). The presence of 15 more species was also noticed but considered doubtful. Almost half of these AS were introduced intentionally. They correspond to restocking programs and are likely the most serious threat to native biodiversity through predation, competition, and hybridization. Commercial activities around aquarium and ornamental species appear as the second source favoring colonization by AS. Implementing protective regulations regarding the import of exotic species in Morocco appears very urgent to protect local native diversity. In addition, detecting and monitoring the expansion of AS within the colonized areas and studies improving biological and ecological knowledge seem crucial to mitigate their possible impacts on native communities and preserve Moroccan freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Gracillariidae is one of the richest families of leaf mining moths, known by its ornamental and orchard plant pests expanding their primary ranges. We here provide a revised checklist of Gracillariidae (Lepidoptera) of Slovenia that presently accounts for 123 species. Among them, four species, Dialectica imperialella (Zeller, 1847), Phyllonorycter abrasella (Duponchel, 1843), Ph. trifoliella (Gerasimov, 1933), and Phyllocnistis valentinensis M. Hering, 1936, are new records for the country. The distribution of the other three species in Slovenia, Caloptilia honoratella (Rebel, 1914), Dialectica scalariella (Zeller, 1850), and Ph. messaniella (Zeller, 1846), is clarified. For the above seven species, short synopses of the bionomics, a current range, and images of biotopes, adult moths and their genitalia are provided. For P. valentinensis sampled at a larval stage, the DNA barcode was obtained to confirm the species identification. Given the known distribution of some of the newly recorded moths in Europe, we believe that these species do not represent a new invasion but rather are discoveries of native species, except for the newly documented Ph. trifoliella in Slovenia, which is likely to be an alien species for the country. [ABSTRACT FROM AUTHOR]

Oenothera speciosa Nutt. is a non-indigenous plant that is widespread in Europe, South America, Asia, and Oceania. Although in its native range it is rarely pollinated by sphingid moths, in Europe and Asia, it was found to be associated with the hummingbird hawkmoth Macroglossum stellatarum (Linnaeus, 1758). However, the plant–insect interaction was negative, and the moths were found with proboscides stuck to the flowers of this plant. This interaction is a relevant conservation issue that requires further studies to assess its ecological impact. This work represents the first record of the negative interaction between O. speciosa and M. stellatarum in Italy. [ABSTRACT FROM AUTHOR]

Invasive alien species are considered the second greatest global threat to biodiversity. This study is aimed at determining the impacts of Parthenium hysterophorus on herbaceous and woody plant species diversity in the Ginir district, southeast Ethiopia. Data on vegetation were collected from the three study sites' four land use types, with each land use type having invaded and non-invaded land units. A systematic random sampling method was used for establishing sampling plots. To examine the impacts of the invasive on native plant diversity, a total of 160 plots (120 plots of 1 m2 on grazing lands, roadsides, and abandoned agricultural lands and 40 plots of 20 m2 for sampling herbaceous and tree (shrub) species, respectively) were established. The number of plots was equally distributed in both invaded and adjacent non-invaded areas. Plant species from each plot were recorded and identified. In each plot, all the individuals of P. hysterophorus were counted, the heights of the five tallest individuals were measured, and the mean height was calculated. The percentage cover of P. hysterophorus was visually estimated. The data were analyzed using both descriptive and inferential statistics. A total of 105 plant species (45 trees/shrubs and 60 herbaceous) belonging to 84 genera and 42 families were documented in the study area. The result showed a strong negative relationship between the density of P. hysterophorus and other plant species richness (r = −0.82, p = 0.013) and species abundance (r = −0.917, p = 0.001) per study site of the invaded community. Species richness in the non-invaded site was higher (105 species) than in the invaded area (63 species), demonstrating the negative impact of P. hysterophorus on local biodiversity. Furthermore, the number of plant families was 42 in the non-invaded area, in contrast to only 32 in the invaded areas, a 23.8% decline. Of the plant communities, similarity indices between non-invaded and invaded sites among different land use types were >50%. It was concluded that P. hysterophorus was one of the most dominant invasive alien species in the study area that reduced the species diversity of various plant species. Putting in place a strategy and effective planning for the control and management of this invasive alien species is strongly recommended. [ABSTRACT FROM AUTHOR]

To identify habitat conditions, indirect ordination methods on the basis of environmental scales are used widely in Europe. However, many alien plants are absent from those scales. Bidens frondosa (Asteraceae) is an invasive alien species distributed widely in Europe. It is becoming a significant part of natural plant communities, sometimes forming monospecific stands. This study aimed to empirically determine environmental factor values using analysis of the flora accompanying B. frondosa in 22 regions of European Russia collected in a 34-year time span. In European Russia, Tsyganov environmental scales are widely used for such analyses. We determined intervals of values for each environmental factor according to Tsyganov environmental scales, namely thermoclimatic scale (TM: 7.3–9.4), climate continentality (KN: 6.0–9.4), climate aridity/humidity (OM: 6.1–8.6), cryoclimatic scale (CR: 5.3–8.8), soil moisture (HD: 9.9–17.6), scale of the soil salt regimen (TR: 5.1–10.7), soil nitrogen availability (NT: 4.4–8.5), soil pH (RC: 4.8–8.8), habitat shading (LC: 2.0–4.5), and soil-moisture variability (FH: 0.7–5.9). These data on environmental factor values can be further used in ordination analyses of plant communities where B. frondosa appears in the subzone of coniferous-deciduous forests of Eastern Europe. Results of this study demonstrate the ecological preferences of this species and can be used to determine conditions of habitats invaded by B. frondosa. [ABSTRACT FROM AUTHOR]

The current knowledge of Sicilian inland water decapod malacostracans is scarce and an updated synopsis on species distribution is lacking. Therefore, we reviewed the checklist and recent distribution of Sicilian inland water decapods based on published and unpublished records and novel observations with the aim of providing an exhaustive repository, also to be used as a sound baseline for future surveys. Overall, five native decapod species occur in the study area, i.e., the atyid shrimp Atyaephyra desmarestii, the palaemonid shrimps Palaemon adspersus, P. antennarius, and P. elegans, and the freshwater crab Potamon fluviatile, and their current local distributions are described. In addition, three alien species were recorded: the common yabby Cherax destructor and the red swamp crayfish Procambarus clarkii, strictly linked to inland waters, and the Atlantic blue crab Callinectes sapidus, a mainly marine species that can also colonise the lower stretches of rivers and coastal brackish waters. The collected data suggest the existence of a partial segregation of native versus non-native species, with the latter currently confined to coastal water bodies and the lower stretches of rivers. Moreover, the exclusively freshwater caridean A. desmarestii and P. antennarius show a parapatric distribution in the study area, which may suggest the existence of mutual exclusion phenomena. The results obtained raise some concerns about the effects of alien species on the native biota, and dedicated monitoring and management strategies should be implemented in order to better understand and mitigate their impact. [ABSTRACT FROM AUTHOR]

Desert springs, which harbor diverse and endemic invertebrate assemblages, are often used as refuge habitats for protected fish species. Additionally, many of these springs have been colonized by invasive fish species. However, the potential impacts of recently established fish populations on invertebrate communities in desert springs have been relatively unexplored. We conducted a mesocosm experiment to assess the impact of both protected and invasive fish on community structure of spring-dwelling invertebrates focusing on zooplankton. Experimental populations of spring zooplankton communities were established and randomly assigned to one of three treatments, (1) invasive western mosquitofish (Gambusia affinis); (2) endangered Mohave tui chub (Siphateles bicolor mohavensis); and (3) fishless control. Final populations of zooplankton and fish were sampled, sorted, identified and counted. The treatment differences of zooplankton communities were analyzed by comparing the densities of six major zooplankton taxa. Further, we performed nonmetric multidimensional scaling (NMDS) to visualize the patterns of zooplankton community assemblages. Four zooplankton taxa, crustacean nauplii, cladocera, calanoid and cyclopoid copepods had significantly lower densities in fish treatments compared to fishless control. Overall, invasive mosquitofish caused a 78.8% reduction in zooplankton density, while Mohave tui chub caused a 65.1% reduction. Both protected and invasive fish had similar effects on zooplankton except for cladocerans where tui chub caused a 60% reduction in density, whereas mosquitofish virtually eliminated cladocerans. The presence of fish also had a significant effect on zooplankton community structure due to population declines and local extirpations presumably due to fish predation. This work shows that conservation-translocations undertaken to conserve protected fish species may impact spring-dwelling invertebrate communities, and such impacts are similar to impacts due to colonization by invasive fish species. [ABSTRACT FROM AUTHOR]

The diversity and structure of plant communities are valuable indicators for assessing landscape quality. Land-use change is one of the main factors considered to affect and have the strongest impacts on biodiversity. In this study, we assessed the effects of the conversion of tropical dry forests and savannahs into agricultural lands on the floral diversity and the structure of the vegetation. For this purpose, we carried out vegetation surveys in 198 plots of 50 m × 50 m. Within each plot, we documented all herbaceous, shrubby, and tree species present. We calculated total, spatial, and local floral diversities by land-use types and characterized the structure of the plant communities. Our results show that the overall floral diversity of the study area remains quite high (483 species of vascular plants from 298 genera and 71 families) and was not strongly impacted by agricultural land use (Pareto inequality index is 23–77). Croplands had the highest spatial (9.4) and local diversities. There was no significant difference between the land-use types in terms of the native species richness while croplands harbored significantly the most alien species. Agricultural land use significantly affected the structure of the plant communities. Trees are very rare in croplands and are frequent in forests and savannahs. The clearing of Guinean dry forests and savannahs for cropping did not automatically lead to a loss of some aspects of ordinary floral diversity. For a better understanding of the effects of land-use change on biodiversity, it would then be more suitable to specify in the studies whether the species concerned are native, alien, generalist, or specialist. [ABSTRACT FROM AUTHOR]

In the present work, we analysed time series data on the introduction of new non-indigenous species (NIS) in the Mediterranean between 1970 and 2017, aiming to arrive at recommendations concerning the reference period and provisional threshold values for the NIS trend indicator. We employed regression analysis and breakpoint structural analysis. Our results confirm earlier findings that the reference conditions differ for the four Mediterranean subregions, and support a shortening of the reporting cycle from six to three years, with a two-year time lag for the ensuing assessment. Excluding Lessepsian fishes and parasites, the reference period, defined as the most recent time segment with stable mean new NIS values, was estimated as 1997–2017 for the eastern Mediterranean, 2012–2017 for the central Mediterranean, 2000–2017 for the Adriatic and 1970–2017 for the western Mediterranean. These findings are interpreted primarily on the basis of a basin scale temperature regime shift in the late 1990s, shifts in driving forces such as shellfish culture, and as a result of intensified research efforts and citizen scientist initiatives targeting NIS in the last decade. The threshold values, i.e., the three-year average new NIS values during the reference period, are indicative and will ultimately depend on the choice of species and pathways to be used in the calculations. This is discussed through the prism of target setting in alignment with specific management objectives. [ABSTRACT FROM AUTHOR]

The flora of the Canary Islands has been subject to botanical studies for more than 200 years. Several biodiversity databases are available for the archipelago. However, there are various drivers of change in real biodiversity and the knowledge about it constantly needs to be kept track of. Island floras are both: exposed to species loss and to species introductions, either through natural processes or by anthropogenic drivers. Additionally, the evolution of endemic plant species plays a substantial role. Endemic species are sensitive to population decline due to small population sizes and possible low competitiveness against incoming species. Additionally, there is continuous progress in systematics and taxonomy. Species names or their taxonomic attribution can be modified. Here, we check published plant lists for the Canary Islands and literature, and compile currently accepted taxa into an updated checklist. For this FloCan checklist, several sources were compiled, checked for completeness and quality, and their taxonomy was updated. We illustrate how far plant names are considered in regional or global databases. This work represents the current state of knowledge on Canary Island plant diversity, including introduced and recently described taxa. We provide a comprehensive and updated basis for biogeographical and macroecological studies. Particularly, the number of non-native species is being extended substantially. The adaptation to standard international nomenclature supports integration into large-scale studies. [ABSTRACT FROM AUTHOR]

Mollusks are the macroinvertebrates most commonly introduced into fresh water. In invaded reservoirs, alien mollusks form a large biomass due to their large size. Climate change, water level regulation, and anthropogenic impacts on the environment lead to the drying up of water bodies and the death of littoral macroinvertebrates. To assess the impact of invasive snail mass mortality on water quality, laboratory experiments on the snail tissue decomposition were performed, the potential release of nutrients into aquatic ecosystems was calculated, and the predicted concentrations of nutrients were verified by field studies. The laboratory experiment showed quick decomposition of the common river snail Viviparus viviparus tissues with release into the environment of ammonium and total phosphorus of 2.72 ± 0.14 mg and 0.10 ± 0.02 mg, respectively, per gram of decomposing tissue. The concentrations of ammonium, nitrates, and total phosphorus at the site of snail death reached 2.70 ± 0.10, 3.13 ± 0.38 and 0.30 ± 0.02 mg/L, respectively. This indicates local contamination of the Novosibirsk reservoir littoral with decomposition products. The aquatic management, water level regulation, and control of undesirable species should take into account the likelihood of water quality decreasing as a result of macroinvertebrate mass mortality. [ABSTRACT FROM AUTHOR]

Evidence so far shows that most alien species (AS) have negative impacts on native biodiversity and are changing biodiversity in almost all environments. Here, we study eight rocky shores at four sites containing reefs with invaded communities and other not-invaded (control) communities, to evaluate the effects of four marine invasive species on biological and functional diversity. We used the adjustment and selection approach of species abundance distribution models (SAD), taxonomic diversity indices and functional diversity indices based on hierarchical grouping matrices (FD—Functional Diversity). In addition to comparing invaded and not-invaded communities, we also performed the same analysis, but removed the invaders (AS removed) from the matrices. The geometric-series model was best adjusted to the majority of communities. The diversity indices suggest that the taxonomic diversity is lower in invaded communities, while the functional diversity indices suggest a change in the functional space of invaded and not-invaded communities, with a greater amount of functional space filled by species in the not-invaded communities. Taxonomic and functional diversity indices were successful in identifying processes that determine the biological diversity of invaded communities, as they seem to obey a pattern that reflects the reduced diversity of invaded communities. [ABSTRACT FROM AUTHOR]

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species. [ABSTRACT FROM AUTHOR]

Biological invasions are deemed to be the second most important global driver of biodiversity loss, right behind habitat destruction and fragmentation. In this study, we aimed at testing if community invasibility, defined as the vulnerability to invasion of a community, could be associated with the characteristics of a given habitat, as described by the composition and structure of its native species. Based on a probabilistic sampling of the alien flora occurring in the temperate wetland Lake Doberdò (Friuli Venezia Giulia region, NE Italy) and using a null-model-based approach, the observed occurrence of Invasive Alien Species (IAS) within sampling units was randomized within habitats. While testing the degree of invasibility for each habitat within the wetland, our null hypothesis postulated that habitats are equally invaded by IAS, as IAS can spread homogeneously in the environment thanks to their plasticity in functional traits that makes them able to cope with different ecological conditions. The obtained results comparing observed IAS frequencies, abundance and richness to those obtained by the null model randomizations show that, for all habitats, invasion was selective. Specifically, a marked preference for habitats with an intermediate disturbance level, a high nutrients level and a medium-high light availability was observed, while an avoidance was detected for habitats characterized by lower levels of nutrients and light availability or extreme conditions caused by prolonged submersion. This method allows us to provide useful information using a simple-to-run simulation for the management of the IAS threat within protected areas. Moreover, the method allows us to infer important ecological characteristics leading to habitat invasion without sampling the environmental characteristic of the habitats, which is an expensive operation in terms of time and money. [ABSTRACT FROM AUTHOR]

Though mountain lakes are generally much less influenced by human activities than other habitats, global and local anthropogenic threats can alter their natural condition. The most alarming threats are climate change, water exploitation and abstraction, alien species introduction, and the medium-long range atmospheric transport of contaminates. Moreover, tourism and mountain farming are two other major sources of organic pollutants that can pose a threat to local aquatic biodiversity. Papers submitted to this Special Issue should be original contributions, with a focus on ecological and morphological characterization, environmental pressures (i.e., alien species introduction, environmental contaminates), and the use of bioindicators/tracers to inform adequate management plans. [ABSTRACT FROM AUTHOR]

This special issue points to the necessity to continue actively working on biological invasions, as invasive species remain a main and global threat for biodiversity through a global homogenization process. This issue includes six research papers, covering a large range of taxa, studying new invasive processes and proposing innovative management solutions. The way forward will be to continue working in close relation with other stakeholders and decision-makers, increase communication efforts, solicit societal feedback, and quickly implement consistent legislation. [ABSTRACT FROM AUTHOR]

Despite the importance for scientific and conservation purposes, the knowledge of the Italian territory is far from exhaustive. New chorological data for 87 vascular taxa regarding the central-southern part of Italy and its two main islands (Sicilia and Sardegna) are presented. Among these taxa, Epilobium nummularifolium, Metrosideros excelsa, and Salvinia minima are recorded as casual aliens for the first time in Europe (excluding Azores and Madeira for M. excelsa), while Cyclamen balearicum and Polygala rupestris are reported for the first time and confirmed for Italian native flora, respectively. Furthermore, several taxa are new or confirmed at regional level. Finally, Lathyrus cirrhosus, Urginea fugax, and Linum tenuifolium are excluded from Italy, continental and peninsular Italy, and Sardegna, respectively. [ABSTRACT FROM AUTHOR]

Seawater warming is impacting marine ecosystems, but proper evaluation of change requires the availability of long-term biological data series. Mesco Reef (Ligurian Sea, Italy) offers one of the longest Mediterranean data series on sessile epibenthic communities, based on underwater photographic surveys. Photographs taken in four stations between 20 m and 40 m depth allowed calculating the percent cover of conspicuous species in 1961, 1990, 1996, 2008, and 2017. Multivariate analysis evidenced an abrupt compositional change between 1990 and 1996. A parallel change was observed in Ligurian Sea temperatures. Two invasive macroalgae (Caulerpa cylindracea and Womersleyella setacea) became dominant after 1996. Community diversity was low in 1961 to 1996, rapidly increased between 1996 and 2008, and exhibited distinctly higher values in 2008–2017. A novel community emerged from the climate shift of the 1990s, with many once characteristic species lost, reduced complexity, biotic homogenization, greater diversity and domination by aliens. Only continued monitoring will help envisage the possibility for a reversal of the present phase shift or for further transformations driven by global change. [ABSTRACT FROM AUTHOR]

Signal crayfish, as an invasive alien species in Europe, have caused impacts on aquatic communities and losses of native crayfish. Eradication of recently established populations may be possible in small ponds (<2.5 ha) and short lengths of small watercourses using a nonselective biocide. Between 2004 and 2012, a total of 13 sites in the U.K. were assessed for suitability. Six were treated with natural pyrethrum and crayfish were successfully eradicated from three. In Norway, five sites were assessed and two sites were treated with a synthetic pyrethroid, cypermethrin, both successfully. In Sweden, three sites were treated with another synthetic pyrethroid, deltamethrin, all successfully. Defining the likely extent of population was critical in determining the feasibility of treatment, as well as the ability to treat the whole population effectively. Important constraints on projects included site size, habitat complexity, environmental risks, cooperation of landowners and funding availability. Successful projects were manageably small, had good project leadership, had cooperation from stakeholders, had access to resources and were carried out within one to three years. Factors influencing success included treating beyond the likely maximum geographical extent of the population and taking care to dose the treated area thoroughly (open water, plus the banks, margins, inflows and outflows). Recommendations are given on assessing the feasibility of biocide treatments and project-planning. [ABSTRACT FROM AUTHOR]