Syzygium australe (Australian brush-cherry; the names Eugenia australis and Syzygium paniculatum have been misapplied to this species in some regions) is native to Australia. It has been introduced and used as an ornamental plant in several regions outside its native range and is invasive in Hawaii and New Zealand. The species was first recorded in South Africa in 1968 and has become a popular and widely traded and planted ornamental species. The first reports of naturalisation in the country appeared in the first decade of the 21st century; the species was subsequently flagged as a priority for investigation and potential regulation as an invasive species. In this paper we mapped the current distribution of S. australe in South Africa, determined its introduction status, and modelled its potential distribution. We also investigated whether cultivated plants are producing fertile seeds and compared such seeds with those produced by plants growing outside cultivation. We recorded S. australe at 268 sites across the country, clustered primarily in the Western Cape province. Naturalised populations have established at three sites, all in the Western Cape. Surveys of these established populations revealed ~ 4000 plants covering an area of ~ 7 ha (representing ~ 2 ha condensed canopy area). These populations were flourishing in riparian habitats in urban areas. Species distribution models suggest that S. australe has the potential to expand its current range in South Africa, primarily in coastal regions. Seeds of both cultivated and naturalised plants showed similar high levels of germinability (both 100%). Building on these findings, we conducted a risk analysis using the Risk Analysis of Alien Taxa Framework, and found S. australe to be of high invasion risk in South Africa. We recommend that all populations outside cultivation be controlled, and that propagation and trade be prohibited. However, except where they occur near riparian habitats, garden plantings do not need to be prioritised for immediate control, and can rather be phased out over time.

Solanum carolinense is a perennial herb native to North America and regarded to be a major agricultural problem in crops and pastures in several parts of the world. In south-eastern Austria, S. carolinense is in a phase of range filling and ongoing spread. Floristic relevés demonstrated that the species infests different crop types, such as soybean, maize and oil pumpkin, and grassland, but also non-agricultural habitats are already invaded. Widespread invasion clusters were found in almost one fifth of the crop fields surveyed, indicating locally severe infestations. A species distribution model shows that only a relatively small part of Austria is currently climatically suitable, but most of it is used for agriculture. The study highlights the need to take effective measures to halt the further spread of the species and to avoid significant yield losses.

During field surveys carried out in north-eastern Algeria, the escape of Gazania ×splendens Hend. & Andr. Hend. was observed; it is reported here as in the process of naturalization for the first time in Algeria and continental North Africa. This hybrid of the Asteraceae family, highly appreciated and widely used in ornamentation, was discovered at a single locality on a coastal dune in the Skikda region, where it is currently colonizing disturbed habitats, in particular the edges of sidewalks. It grows on sandy soil, spreads from seeds and seems to have escaped from the countless green spaces in the region. Gazania ×splendens manages to cope well with summer heat and drought and has maintained itself at the site for more than three years. Field photos and a map marking the escaped populations and the cultivated populations in their vicinity are provided.

The introduction of alien species in insular ecosystems is one of the main causes of population decrease and extinction of native biodiversity. This is the first time that the arrival of Cydalima perspectalis in the Balearic Islands has been reported, which makes it possible to complete the distribution of this Asian moth in Europe. The box tree moth was reported on three out of the four islands that compose the archipelago. However, it seems to be only established in Mallorca because of the wider distribution of Buxus balearica and B. sempervirens as the host plants.

An undescribed phytophagous wasp belonging to the Tetramesa genus (Hymenoptera: Eurytomidae), that is native to South Africa, is currently being investigated as a potential weed biological control agent for the invasive grass Eragrostis curvula (Poaceae) in Australia. Host-specificity testing is underway in South Africa, but the wasp has not been exported into quarantine in Australia and further research is required before it could be considered for release. Here, we used DNA barcoding to demonstrate that Tetramesa specimens collected on invasive E. curvula populations in Australia represent the same wasp species currently being investigated in South Africa. We discuss our findings in the context of developing a biological control programme against E. curvula in Australia and the potential risk posed to native Australian grasses.

The solitary ivy bee Colletes hederae has recently naturally colonised the British Isles. It was first recorded in Britain in Dorset, near the south coast, in 2001. By 2021 it had reached Scotland and Ireland. It had spread to Sussex, some 100km east of Dorset by 2004, but occurred only locally. In autumn 2020, to determine the distribution and abundance of the ivy bee in Sussex, we made three surveys of 100 insects foraging on ivy flowers at 57 locations during the female flight period. We found the ivy bee at all 57. It was the second most abundant insect (22%), being outnumbered by social wasps (Vespula spp. 42%), but was more numerous than honey bees (Apis mellifera 14%). In autumn 2021 we made a further presence or absence survey at 17 additional locations, and the ivy bee was seen at each one. The results show that the ivy bee is now found throughout Sussex and is abundant. Comparisons of site characteristics showed no significant effect of urban versus rural locations on ivy bee relative abundance. It was, however, significantly more relatively abundant on Downland compared to Weald and Coastal Plain locations, and on chalk and sand derived soils compared to clay and alluvium derived soils. Possible reasons for the success of C. hederae in Britain are discussed.

The northern spruce bark beetle, Ips duplicatus (Sahlberg), has invaded Central Europe in the past century and continues to spread southwards and westwards. It has caused damage in some parts of Europe in recent decades and poses a serious threat to spruce forests across the continent. From 2018 to 2021, we conducted intensive monitoring to determine the status of I. duplicatus in Slovenia. We used different types of traps and pheromone lures that attract I. duplicatus beetles and took bark samples from bark beetle-infested trees. Of the 26 traps used during the four years of monitoring, I. duplicatus was found in 16 traps in the central part of Slovenia in 2020. Adult beetles were caught in traps containing both I. typographus and I. duplicatus lures. The identity of this species was confirmed using morphological keys and molecular methods. One to five I. duplicatus beetles were found per trap, totaling 25 specimens. However, we did not confirm any I. duplicatus in samples taken from trees in 2021. We conclude that I. duplicatus is present in Slovenia, but our results suggest that the species is only present locally and that the population is small.

Five terrestrial slug species are reported from Hungary, either for the first time or confirming earlier records that had been considered unreliable: Limacus maculatus, Deroceras invadens, Ambigolimax valentianus, Ambigolimax parvipenis, and Milax nigricans. In all cases identification was supported by anatomical examination and barcoding sequences of the COI mitochondrial gene. For M. nigricans we also sequenced individuals of this species from Italy and France so as to establish differences to sequences of M. gagates. Most records came from garden centres in Budapest and from two botanical gardens; these habitats may therefore be crucial in the spreading of non-indigenous species. A Facebook appeal was used to involve citizen scientists in searching for further sites for L. maculatus, but the Limacus populations reported proved all to be L. flavus. Studies over the last four years have added altogether seven slug species to the 26 hitherto recognised in the Hungarian fauna. This demonstrates the importance of continuing to check for additional introduced species.

Biological invasion is one serious threat to global biodiversity, economics and sustainability. Under the era of globalization, emerging non-native species are still accelerating at an unprecedented rate. Identifying new field records of non-native species at early stages is critically important to develop effective prevention and management schemes. Here, we conducted field surveys and applied genetic analysis to identify new recordings of non-native amphibians in Shenzhen (a megacity of South China with enormous trade volume). We recorded a total of three non-native amphibians (Ceratophrys ornata, Hoplobatrachus rugulosus and Eleutherodactylus planirostris) in the field with two having establishment evidence (H. rugulosus and E. planirostris). Further ecological niche modeling based on climatic and habitat variables also detected a high habitat suitability of the two species with field establishment evidence and a low habitat suitability for the other three species (C. ornata, Rana catesbeiana and Xenopus laevis) lacking establishment evidence or field observation with only records in the market and database. We recommend more systematic surveys covering wider areas to investigate the establishment of non-native amphibians to stop their further invasions in China.

We report the first record of a non-native species of Antithamnion detected on the eastern shore of Nova Scotia, Canada and assign these collections to the Asian Antithamnion sparsum based on available morphological and molecular data. Two collections of this non-native species were made at three sites in the subtidal (10 m) in August 2021, and it was observed as a dominant subtidal (10 m) turf at an additional four sites from April to August 2022. We describe here morphological traits that match the original type description of A. sparsum and generated rbcL 3P data (851 bp) for two 2021 collections which closely match a record in Genbank from South Korea that is likely A. sparsum (99.9% identity). These collections represent the first occurrence of A. sparsum in the Northwest Atlantic.

In the last decades, species of Didemnidae (Tunicata: Aplousobranchia) have attracted attention for overcoming marine barriers, invading coastal areas and causing negative impact to local biodiversity and human facilities. Six years ago, large colonies of a didemnid species were observed growing on artificial substrate in a port in the southeastern Brazilian coast. Samples were collected and morphological and genetic analysis were done. In morphology, the species is similar to D. vexillum in colour, tunic surface consistency and internal organisational system. The morphology of the zooids is similar to D. perlucidum but differs in the number of stigmata, coils of sperm duct, spicules size and larval aspects. Phylogenetic analysis based on the COI gene indicated the Brazilian samples form a monophyletic group distinct from other species, including D. perlucidum, D. vexillum and D. pseudovexillum. Didemnum sp. demonstrated high reproductive activity during the winter season and can grow over native and non-native species, showing high invasiveness potential. Didemnum sp. was not recorded anywhere else until now and based on our findings it should be categorised as a non-native species. We highlight the need of a monitoring program and the evaluation of plans for eradication of the species.

In recent years the number of non-indigenous marine species has been increasing in Icelandic waters. In May 2019, a razor shell (Ensis sp.) was found for the first time in Iceland. Since then, living and empty razor shells have been discovered at several locations in Southwest Iceland. Upon morphological examination, the specimens were thought to belong to either Ensis leei or Ensis terranovensis, both native to the east coast of North America. Molecular analysis, using COI and 16S rRNA markers, showed that the Icelandic specimens belong to the latter species. Native populations of Ensis terranovensis have, until now, only been reported in Newfoundland, Canada. This represents the first record of E. terranovensis outside its native range. The Newfoundland’s razor shell has most likely arrived in Iceland as larvae discharged with ballast water. Based on the sizes of specimens found in Iceland, the species is likely to have arrived several years prior to this first record. Presumably it has already established viable spawning populations that are likely to spread along the coast.

Two live specimens of American lobster, Homarus americanus, were observed in very shallow waters, in Caesarea, the central Mediterranean coast of Israel at the end of 2022. This is the first record of this species or any clawed lobster, family Nephropidae, in the warm southeastern Mediterranean. The carapace lengths of the lobsters were 92 and 94 mm, which corresponds with weights of around 600–640 grams, like that of live clawed lobsters imported to Israel from the North-Eastern USA. Although the origin of these lobsters is unknown, it is assumed that they have been released from a restaurant or a cruise ship. They may survive the winter in the Israeli water, but the high temperatures of the sea water during late-spring and summer in the southern Levantine basin will be stressful and lethal for them.

Studies of alien aquatic invertebrates in 2021–2022 covered fresh marine and transitional waters mostly within the boundaries of the Danube Biosphere Reserve. As a result of these studies, important new findings of six species of aquatic macroinvertebrates were obtained: Menetus dilatatus (Gould, 1841) is first indicated for the Danube Basin, and three marine species (Arcuatula senhousia (Benson, 1842), Polydora cornuta Bosc, 1802 and Streblospio gynobranchiata Rice & Levin, 1998) for the first time for Ukrainian Danube Delta. For two species (Pectinatella magnifica (Leidy, 1851) and Ferrissia californica (Rowell, 1863)), new localities were found within the delta. In the case of M. dilatatus, the pathway of entry into the Danube Delta is an absolute mystery. The most likely pathway of dispersal of this species is natural dispersion, both along the river network and associated with waterfowl, however, the large distance between the Danube Delta and the nearest locations in Western Ukraine makes direct transportation unlikely. In all probability, the similarity of this species with local species leads to the formation of cryptic populations, not identified by researchers, which may be intermediate stages of species expansion towards the Northern Black Sea area.

Human land-use plays an important role in the distribution of aquatic invasive species. The establishment of these species may have an unpredictable impact on their new environment. We analyzed the establishment of M. tuberculata, an invasive species, and its effect on the mollusc community in Ouagadougou’s reservoir No.3. Mollusc samples were collected using an Ekman grab through sampling points randomly distributed across the whole reservoir. Collected specimens were sorted, preserved in alcohol at the field site and transported to the laboratory for identification. Species diversity, abundance and distribution were analyzed. Among the five species encountered, M. tuberculata and L. varicus were identified for the first time in this reservoir. M. tuberculata had the highest relative abundance (60.83%) and the highest density. The evenness was less than 0.5 for 72.5% (i.e. 21) of sampling points, reflecting the relative dominance of a single species, M. tuberculata. In terms of spatial distribution, the most widespread species in the study reservoir was M. tuberculata, followed by C. aegyptiaca and B. unicolor. M. tuberculata distribution in the reservoir mostly overlaps that of B. unicolor (0.45). Renewed monitoring efforts are needed to better understand the evolution of mollusc species in freshwaters of Burkina Faso to understand species extinction risks as well as the potential use of mollusk diversity measures as water quality indicators.

Recent sampling of the upper part of the Seine estuary (oligohaline, freshwater reaches) has led to the observation of the non-indigenous amphipod Chelicorophium curvispinum for the first time in the downstream part of the Seine Basin (between the Tancarville Bridge and Paris). Specimens were collected using a suprabenthic sledge along a salinity gradient ranging from freshwater to mesohaline, with observations of C. curvispinum all along this gradient. Samples collected were characterized by a relatively small number of individuals, reaching a maximum abundance of 15 individuals / 100 m³ when temperatures were the highest, during the summer. The sex ratio was dominated by females, with approximately twice as many females than males. Interestingly, adults reach a size which allowed the reproduction of the species, but no ovigerous females were observed. Despite the rapid expansion of C. curvispinum in the Seine estuary, this study cannot assess whether this species should be considered as invasive in the Seine Basin. Nevertheless, as the sampling was carried out within the navigation channel, further observations will be necessary to determine the abundance of this species on soft and hard bottoms of the riverbanks.

The invasive Australian redclaw crayfish (Cherax quadricarinatus) has a long history of introduction in Mexico. Since its introduction in 1986 for aquaculture production purposes, it has been cultured in several regions of the country without considering the probability of accidental escapes and the threat to biodiversity. Here the presence of the Australian redclaw crayfish is reported for the first time in the Sierra Gorda Biosphere Reserve (SGBR), which harbors vast biodiversity in biological groups and ecosystems. Six males and one ovate female with a maximum total cephalothorax length of 73.7 mm and a weight of 66.7 g were collected. The presence of reproductively active individuals in this Protected Natural Area represents a new record of this invasive species in Mexico that adds to the list of non-native species within the SGBR. It also means a potential threat to the native aquatic biodiversity of the SGBR, given the resistance and dispersal capacity of this invasive species and the potential negative impacts on the ecosystem. A better understanding of the distribution and invasion dynamics of the redclaw crayfish is required to evaluate and develop management strategies to reduce its spread and potential impacts within the SGBR.

The marbled crayfish, Procambarus virginalis (Lyko, 2017) is a novel parthenogenetic freshwater species that has rapidly colonized diverse habitats in Europe and Madagascar. Here we describe the first wild population of marbled crayfish in the Middle East. Numerous specimens, including gravid females, were collected in the waters of a spring on Mt. Carmel, Israel. The results from phenotypic, morphometric and genetic analyses showed the close relationship with other known populations, consistent with the clonal structure of the global marbled crayfish population. Our findings represent a considerable expansion of the known distribution range and further illustrate the role of anthropogenic activities in the dispersal of marbled crayfish.

Lake Batur is one of the priority lakes for the government initiative to control the damage, and to restore the condition and function of the critical lakes. The degradation in biodiversity due to the invasive and non-native species could raise ecological, economic, and socio-cultural problems for the community. In Lake Batur, there are several fish introduction activities since 1935. Many introduced fish species have turned invasive and could alter the structure of fish communities. It is important to have a solid understanding of how invasive species affect an ecosystem and its biodiversity. Despite numerous studies on fish diversity in Lake Batur, the accurate information on fish diversity and the presence of non-native species in Lake Batur is still not completely known. This paper aims to investigate the diversity of fish in Lake Batur to provide accurate information about the composition of fish species and the presence of existing non-native and invasive fish in Lake Batur. We collected fish samples during the dry season from 30 August–5 September 2022. We used experimental gillnets (30 × 2 m, with mesh size of 16 mm; 25 mm; 37.5 mm; 50 mm; 62.5 mm; and 75 mm), fish nets from the fishing communities (mesh size of 50–75 mm), fishing rods, and scoops. Direct identifications were conducted for the fish samples in the location. For unidentified fish, we preserved the fish sample for further identification. A total of 1104 fish samples from lakes and floating net cages with five different stations were collected. In contrast to the others station, station 4 Abangsongan has all fish species. We obtained 17 species distributed among 8 families. Cichlidae is the most dominant fish family, including the non-native species Nile tilapia (Oreochromis niloticus) and Midas cichlids (Amphilophus citrinellus). Furthermore, Midas cichlid has become invasive with a very rapid increase during the last 10 years in Lake Batur. For Poecilidae family, Bonylip barb (Cyclocheilichthys apogon) is clearly identified for the first time in this study. This study concludes that the invasive species, or non-native Indonesian species represented by Cichlidae species, are a significant issue for fish diversity in Lake Batur.

The invasive western tubenose goby (Proterorhinus semilunaris) was introduced in the Great Lakes in the 1990s. Since then, its range slowly expanded downstream into Ontario’s portion of the St. Lawrence River. This rapid communication reports on the first occurrence of a western tubenose goby found in Lake St. Francis (St. Lawrence River, Quebec) in August 2022. The specimen, the study area and the sampling methodology are described while hypotheses about its presence and expansion are explored.