Monitoring the occurrence of new alien species among native flora is the first prerequisite for preventing their later invasive spread. During the last decade, we recorded data regarding 25 alien taxa new to Slovakia including 21 casual and 4 locally naturalised species, with ornamental plants predominating significantly. The locally naturalised species Cenchrus flaccidus, Cotoneaster zabelii, Doronicum pardalianches and Panicum virgatum are able to spread to native habitats and thus represent the greatest risk to native plant species in Slovakia.

Studies have reported a total of 326 naturalized plant species in the South Korea; however, research on the distribution of naturalized plants across the island regions has not been conducted. The objectives were to analyse the distribution of naturalized plants in these island regions, which is an ecologically vulnerable space. A total of 113 islands – 53 inhabited and 60 uninhabited – with > 100 native species were selected for this study, and a list of 321 naturalized species was compiled based on available literature. The relative frequency of occurrence and ratio of naturalized plants to native plants was calculated for each species. There were 184 species of naturalized plants found distributed in the island regions, 10 of which are invasive. Four species had high relative frequencies of occurrence (> 0.5) but accounted for only 2.2% of naturalized plants in the regions. All islands shared 15 of the 20 most common species, but the remaining five were specific to individual islands. This approach shows promise for future monitoring of the naturalized species distribution. Currently, the Korean government (Ministry of Environment) has established the second invasive species management plan at the national level (2019~2023). Species that have not yet been introduced to South Korea and those that have already migrated and have settled are managed separately. Because island areas are geographically isolated, the impact on existing native plants may be more extreme than on land if exotic plants are introduced. In this regard, the importance of managing the island area is further emphasized.

Lysichiton americanus is a robust rhizomatous plant native to the Pacific part of North America. This species was introduced to Europe in Great Britain at the beginning of the 20th century and since then, due to its aesthetic value, it has been used as an ornamental plant in numerous European countries. Since then and after numerous introductions, established populations of this plant have been reported in 9 European countries. It was classified by the European Union as an invasive non-native plant species. The current study describes the first record of a wild-growing population of L. americanus in Poland. It was found in an overgrown former pond, neglected for about 50 years, near the rural park located in the Sudetes Mountains (south-west Poland). Apart from its distribution, its phytosociological affiliation and status in the Polish flora are also described.

Oenothera jamesii Torrey & A. Gray (Onagraceae), a native of the southwestern United States and adjacent parts of Mexico, was found along a streamside near Aksu village in Çağlayancerit and along roadsides in Andırın district of Kahramanmaraş Province in the Eastern Mediterranean Region of Turkey. It is the fourth Oenothera species noted so far in Turkey. This species is morphologically similar to Oenothera biennis Linnaeus and O. stucchii Soldano. It is distinguishable from other Oenothera species in Turkey by the following combination of characters: stem very long (up to 2 m) and erect, petals yellow and 40–50 mm in length, and very long hypanthia of (6–)8–12(–16) cm in length. A full botanical description, seed surface sculpture in SEM, habitat features, field photographs and a distribution map are provided, as well as an identification key to the genus Oenothera in Turkey.

A new alien species in the flora of Uzbekistan, Ranunculus sardous Crantz, was identified during a study of plant specimens at the National Herbarium of Uzbekistan (TASH) and in field surveys. R. sardous is native to Europe and is reported as an alien species in many other regions, including North America, Australia, China, India, Japan, and Korea. This species was first observed in Uzbekistan in March 2012, with further records in different regions of the country. Field observations confirmed the presence of at least ten populations of this species in the Tashkent and Namangan regions, Uzbekistan. We consider it a locally naturalized alien that might invade both ruderal and segetal plant communities. We modelled the suitability that may drive the future distribution of this new alien species resulting from global climate change based on future climate scenarios and ensemble modelling. The model predicted an overall low suitability for the current climate in Uzbekistan, while suitability would decrease under the Representative Concentration Pathway 8.5 by 2070. The invasive status of R. sardous was assessed using its degree of resistance, frequency of occurrence, and ecological-phytocoenotic features. According to the methodology applied, R. sardous scored 9 points, which indicates a possible invasion risk to natural flora. Therefore, we suggest prioritising an eradication plan before the species becomes too widespread.

The ant Nylanderia fulva, is a native species of southern Brazil that has been introduced in several countries in the Nearctic, Neotropic and Palearctic. In the areas they invade, they establish very dense and extensive super colonies. Here, N. fulva is reported for the first time in Panama. All the stages and castes of this species were collected in six localities of the Boquete District, Chiriquí Province. We advocate for additional local searches and studies for N. fulva to provide information on the status of its distribution and to generate information on the various agricultural implications.

The genus Megabruchidius has been recorded recently in many European countries. This study reports the first records of M. tonkineus and M. dorsalis from Turkey. Both species were detected in the hard seeds of Gleditsia triacanthos. M. tonkineus emerged from pods collected at all locations, while M. dorsalis was found at two locations. Both species were collected in the same trees in Istanbul and Düzce Provinces.

Xylosandrus compactus (Eichhoff), a polyphagous invasive pest native to Asia, was first detected on the European continent in Italy in 2011. It has since been recorded in five additional European countries, France, Spain, Malta, Monaco, and Greece. The present study reports for the first time the presence of the species in Turkey. As a result of our literature review, there is no record of the genera Lonicera and Crataegus as host plants of X. compactus. We identified new host plant species to X. compactus: Lonicera pileata var. yunnanensis (Franch.) Bernd Schulz and Crataegus monogyna Hayek. In addition, we determined the black twig borer on Fagus sylvatica f. pendula (Lodd.) Dippel. Laurus nobilis was the host plant infested by X. compactus at all localities but one locality.

Native to the Americas and the Caribbean, the highly invasive agricultural pest Spodoptera frugiperda (fall armyworm, FAW) gained global prominence in 2016 when its presence was confirmed in Nigeria and São Tomé and Principe. Since then, it has been reported from over 70 countries in the African and Asian continents including the Near East, South East Asia, and Oceania. In this report, we provide confirmation of the presence of the pest in the northeast province of Papua New Guinea (PNG) via molecular analysis (i.e., DNA barcoding) of the partial mitochondrial DNA cytochrome c oxidase subunit I (mtDNA COI) gene. Our analyses identified the suspected insect species as S. frugiperda with a gene sequence characteristic of the R-strain. We discussed the biosecurity implication of detecting FAW in this PNG region that neighbours the Bismarck Sea and the New Britain Province as well as the Solomon Islands. We further highlighted the need to survey for beneficial insects of FAW to assist with developing integrated pest management strategies, and to apply whole genome sequencing approach to characterize insecticide resistance gene in FAW populations from this region.

The invasive pest tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), was observed for the first time in the Udaipur district of Southern Rajasthan, India, during 2018–2020 under field and protected cultivation in tomato. Morphological and molecular identification (amplifying cytochrome oxidase gene (CO-I) of mitochondrial DNA) was made to confirm the occurrence of this new invasive species. The developmental period of T. absoluta has four stages viz; egg, larva, pupa and adult. The duration of the incubation period, first, second, third and fourth instar larvae were observed at 4.52 ± 0.68, 2.38 ± 0.50, 3.95 ± 0.80, 3.43 ± 0.51 and 2.57 ± 0.51 days, respectively. The hatching rates of the eggs were 94–97 per cent. The average length of first, second, third and fourth instar larvae was measured at 0.610 ± 0.037, 1.577 ± 0.067, 3.917 ± 0.121 and 7.379 ± 0.176 mm, respectively. A total larval period of 10–15 days was recorded, with a mean of 12.33 ± 1.35 days. The pupal phase lasted 10–12 days on average, with a mean of 10.95 ± 0.86 days. Adult longevity was 12.00 ± 1.41 days on average, with a range of 10–14 days. T. absoluta had a life span ranging from 30 to 40 days, with a mean of 35.43 ± 3.56 days.

Chaoborus phantom midges have a cosmopolitan distribution and are often abundant inhabitants of lentic water bodies during their immature stages. Chaoborus punctipennis, a native species of lakes in the USA and Canada, is reported for the first time in the Palaearctic region in Ehime Prefecture, Japan, as invasive taxon. The species is easy to identify in the larval, pupal and adult stages using morphological keys, and has a distinct DNA barcoding (COI) profile. In order to monitor and manage the species in Japan, we recommend creating targeted inventories of lakes and ponds at Ehime and in neighboring prefectures.

Early detection of exotic species and rapid dissemination of information are both essential for risk assessments and preventive measures to be implemented early. In this context, we report the first mention of Arion vulgaris in Quebec (Canada). This species is considered as the most important slug pest in Europe and is of particular concern in North America where its presence has rarely been documented. Identifications were based both on a 16S rDNA gene segment and on genital morphology. Our results confirmed the northernmost successful introduction of A. vulgaris in North America. This new record emphasizes the need to acquire more data on the invasion of this species in North America.

Habitat destruction by destroying the foundation species is one of the important damages caused by invasive species. The red alga Kappaphycus alvarezii is commercially important as a source of carrageenan and has been introduced in many countries for commercial cultivation. Due to its invasive potential, this red alga has been widely reported to be a big threat to coral reefs in many reef regions including the Gulf of Mannar (GoM) in India. Here we report the invasion of red alga K. alvarezii to new reef sites in Valai and Thalaiyari Islands within GoM and the coral mortality caused in the newly invaded sites from 2019 to 2021. We also discuss the geographical extension of K. alvarezii within GoM from its initial invasion point and its impact on corals from 2005 to 2021. During our regular reef monitoring surveys within GoM, we found K. alvarezii to be overgrowing live acroporan corals of Valai and Thalaiyari islands of GoM for the first time in May 2019 and we used standard underwater protocols to assess the impact of the alga on corals at different time periods between May 2019 and March 2021. Live coral cover in the invaded area decreased by 9.1% in Valai Island and by 3.9% in Thalaiyari Island due to the coral mortality caused by K. alvarezii during the study period. K. alvarezii was observed to overgrow live corals and kill them eventually at the affected sites. Acropora branching morphotype was found to be the most affected by K. alvarezii. Various measures including manual removal have been taken to keep the invasion under control. In spite of the efforts to eradicate K. alvarezii from the reefs of GoM, it remains a persistent threat to the survival of corals. We emphasize the importance of properly managing the already stressed and ecologically sensitive reef resources of GoM from the invasion of K. alvarezii in order to guarantee the long-term livelihood benefits of dependent fisher-folk.

The knowledge and control of invasive species are essential in the management of marine ecosystems. The Mediterranean Sea is one of the marine areas with the highest number of invasive species detected, most of them invertebrates. On a smaller scale, colonization by non-native species in coastal lagoons depends directly on their connectivity with the adjacent sea and on the changes in their environmental conditions induced mainly by human interventions. In this study, the cirratulid species Timarete caribous Grube, 1859, native from the Western and Central Atlantic Ocean, was detected for the first time in a Western Mediterranean coastal lagoon, the Mar Menor. It has been found in dense aggregates on both artificial and natural rocky substrates, mainly in the most important communication channel with the Mediterranean Sea. Following the evolution of this NIS will be important for understanding the dynamic and spread of the species and its possible effects on the indigenous biological communities.

The sabellid polychaete Bispira polyomma Giangrande & Faasse, 2012 was found during summer–autumn 2021 in substantial numbers in two adjacent marinas in Plymouth, SW England. These are apparently the first UK reports, coming over a decade after the species’ discovery and description, as a presumed non-native, in the SW Netherlands. Further morphological details of the species and notes on variation between individuals are provided. It seems probable that records of Bispira fabricii in Le Havre commencing in 2010, and at other sites on the French north coast, also relate to B. polyomma. An apparent association with marinas and ports suggests roles for recreational boats and commercial shipping in the dispersal of this species.

This study reports the first record of the biofouling mussel Mytella strigata (Hanley, 1843) in Beibu Gulf, China. Phylogenetic analysis based on the mitochondrial DNA cytochrome c oxidase gene sequences demonstrated a close relationship between mussels in Chinese seas and those in Singapore, Venezuela, India, the USA, the Philippines, Brazil, Colombia, Ecuador, and Trinidad. The results of multiple species delimitations showed that the mussel was Mytella strigata. Analysis of the haplotype network indicated that the American brackish water mussel may have invaded China from Colombia or other Asian waters through ships docked in ports or biofouling on the hulls. Mussels attach to oyster shells in large quantities. The minimum shell length of mussels collected in Guangxi Province was 23.9 mm, which exceeded the minimum length for sexual reproduction. The identification of Mytella strigata in Beibu Gulf represents the sixth record of this species from the Indo-Pacific region. In addition, the mussel was also found have invaded Fujian Province. Alien marine species may cause many negative effects and have the potential to harm the invaded ecosystems. Therefore, the distribution of this species within Chinese waters and potential damage caused by this mussel to the ecosystem and economy must be determined. The findings of this study will also provide a reference for formulating management policies for invasive species.

Biological invasions can cause significant changes in the abundance and distribution of species in recipient communities. The effect of invasive species on native biota is now one of the most addressed topics in studies of biological invasions. On March 20, 2022 two juvenile individuals of a never-before-seen mussel were detected on a mussel farm during cleaning activities in the Arraial do Cabo Marine Extractive Reserve (MER), Brazil. The brilliant green color of the margin of the predominantly brown shell was the initial characteristic used to identify the specimens as the Asian green mussel Perna viridis. Biometric features of both the farmed mussel Perna perna and P. viridis were compared to estimate age, and photographs were taken of the anatomical structures. Similar ages of mussel species in farm lanterns suggested that P. viridis may have been present, but overlooked, on nearby shores during spat collection, though no mature individuals were seen. Alternatively, marine farms may be more susceptible to invasion by other bivalves, as has been reported at other locations. This third record in the southwest Atlantic (Brazil) extends the range by 110 km eastward from the first report four years previously. With a port and harbor nearby, the most probable vector of introduction to the region was fouling on small boats. We fully expect P. viridis to continue its range expansion along the southwest Atlantic coastline. MERs provide a model of ecosystem and resource management which combine sustainable development and the conservation of natural resources to benefit artisanal fishers and other stakeholders. It is therefore important to establish long-term programs for monitoring, prevention and control of biological invasions at MERs, especially at Arraial do Cabo, which seems to be an invasion hotspot and, by its very nature, is particularly sensitive to marine biological invasions.

An individual crucifix crab Charybdis (Charybdis) feriata was recorded in the northern Ligurian Sea (Genova, Italy) in February 2022. This non-native species was observed previously twice off the coast of Catalunia (Spain) and once in the southern Ligurian Sea (Livorno, Italy). As the species was “credited at least two reliable records, distinct in time and/or space” in the Mediterranean Sea, it is now considered as “established” following the Commission Internationale pour l'Exploration Scientifique de la Méditerranée (CIESM) classification. The potential invasiveness of C. (C.) feriata in the Ligurian Sea and the broader western Mediterranean Sea was evaluated through the screening tool Aquatic Species Invasiveness Screening Kit (AS-ISK) v.2.2. Results highlighted that the potential of the species being invasive in the screened area is in the lower range of the “medium risk” and environmental parameters are the main limiting factors for the reproduction of the crucifix crab, suggesting that the western Mediterranean Sea is not a suitable environment for the settlement of C. (C.) feriata. Through the application of the quantitative risk screening tool AS-ISK, this study shows that C. (C.) feriata should not be considered as an “established” non-native species as suggested by the CIESM classification. Future work should focus on integrating quantitative evaluations of invasiveness through risk screening tools such as AS-ISK also in the CIESM classification process, being the main reference for non-native species classification in the Mediterranean Sea.

The findings of the crabs Arcania brevifrons and Macrophthalmus (Macrophthalmus) indicus, native to the Indo-West Pacific Ocean and Red Sea, and to the Indian Ocean and Red Sea, respectively, in 2021 are described from Rhodes Island, Greece. This first record of the leucosiid A. brevifrons in Hellenic waters and the Aegean Sea documents the westward expansion of its Mediterranean distribution. Two individuals of the introduced macrophthalmid M. (M.) indicus were found in the stomachs of silver-cheeked toadfish (Lagocephalus sceleratus), a fish species that itself is invasive. For both species, DNA barcoding was performed using the standard mitochondrial marker cytochrome c oxidase subunit I (COI). While the identification of A. brevifrons was genetically confirmed, M. (M.) indicus individuals were morphologically identified. There were no M. (M.) indicus genetic samples available in the nucleotide database of GenBank, hindering the ability to genetically confirm species identification. However, M. (M.) indicus had previously been detected 12 years ago in the same area.

A previously unreported freshwater sponge species was discovered from the Tama River in Tokyo Prefecture and the Sagami River in Kanagawa Prefecture, Honshu, Japan, using data and specimens from the National Census on River Environments. The sponge was identified as belonging to Heteromeyenia latitenta (Potts, 1881). The lack of reports of this species in previous surveys and the restricted distribution of the gemmules as documented in this report suggest a recent introduction. This is the first record of the species from Japan. We describe the morphological characteristics of this species and compared ITS2 rDNA of sequence data of this species with other freshwater sponges.

The planarian Girardia tigrina sensu lato is the most successful freshwater invasive triclad. While Antarctica remains a continent without reports for this species, the single African record is unreliable. Therefore, the species is still unknown on this continent despite the presence of adequate water masses for its occurrence. Here, we report the finding of G. tigrina sensu lato in Morocco at Oued Fès, which constitutes probably its first record in the entire African continent. Despite being located in only one out of more than 100 localities sampled by us, ongoing investigations could soon reveal more occurrences of the species in the country and the rest of the continent.

The invasive Asian date mussel Arcuatula senhousia has now been recorded from the Shatt Al-Basrah Canal in the south of Iraq. High densities of up to 102 ind.m^-2 were found on rocky substrates in the intertidal zone during March 2020. The species was confirmed based on morphological characters of the shell. We hypothesize that the initial introduction was associated with shipping, with secondary dispersion into the Shatt Al-Basrah canal. It is possible that the species could extend its distribution into the Shatt Al-Arab and northern Arabian Gulf naturally or by additional anthropogenic means.

During a statewide crayfish survey of Montana, we documented the southern plains crayfish Procambarus simulans for the first time in the state. Procambarus simulans is native to, and commonly found in, southern and central US states, including Arkansas, Colorado, Kansas, Louisiana, New Mexico, Oklahoma, and Texas. We found this species in a single location, the Miles City State Fish Hatchery, in eastern Montana. At 46.38 degrees north latitude, this is the northernmost population of the species reported. The presence of multiple size classes suggests that the crayfish can overwinter and reproduce in Montana and have been at the location for at least several years. The source of introduction, current extent of spread, and ecosystem impacts are unknown, and investigation is needed to understand the source and effects of this novel species on native crayfishes and other aquatic species.

Cherax quadricarinatus (von Martens, 1868) is a large parastacid crayfish (Decapoda: Parastacidae) native to Australia and Papua New Guinea. Due to various factors, C. quadricarinatus is an emerging invasive species in an increasing number of regions across the world. Deleterious ecological effects of C. quadricarinatus introduction have been documented in many of these regions, and its spread has been monitored and restricted where possible. Previously, only a small, isolated population of C. quadricarinatus in southern California has been reported within the continental United States. Here, we report the collection of three adult C. quadricarinatus from Brownsville, Cameron County, Texas, the first record of this species in the state and only the second record for the continental United States. Given the connectivity of aquatic habitats in the area and the duration for which the population has likely been present, there is evidence that C. quadricarinatus is poised to invade subtropical watersheds of the southern United States. The ecological effects of C. quadricarinatus on aquatic ecosystems in the region are not yet fully understood, but further research is warranted to effectively mitigate negative impacts that may occur and to guide efforts to manage or eradicate these populations.

The redhead cichlid, Vieja melanura (Günther, 1862), is a freshwater and brackish water fish native to southern Mexico and Costa Rica. It was introduced into China as an ornamental fish species in the 1990s. During a comprehensive fish survey in Hainan Island conducted in April and August 2019, twenty redhead cichlid individuals, including two mature males, four mature females and fourteen juveniles, were captured at four sites in the Nandu River. This finding reveals that this species has successfully established feral populations in Hainan Island. This is the first report of the invasion success of redhead cichlid in Hainan Island, even in China. The redhead cichlid is very likely to compete with native species (e.g., Culter recurviceps) by occupying similar niches, thereby threatening the survival of native species and changing food webs, ecosystem structures and functions. Local governments and environmental protection organizations should carry out surveys to monitor the redhead cichlid invasion and implement interventions to prevent further spread. The escape of ornamental fishes to natural water bodies is an important contributor to elevated invasion risks, which should be paid attention to globally.

The western mosquitofish, Gambusia affinis (Baird & Girard, 1853), from North America, is considered one of the 100 worst invasive species in the world. In October 2020, sixteen individuals of western mosquitofish were captured from the Eastern Himalayas of China, making this the first record of western mosquitofish in the region. Since the Eastern Himalayas is part of the Himalaya Biodiversity Hotspot, mosquitofish could represent a potentially significant threat to local biodiversity in the whole Himalaya or the Qinghai-Tibetan Plateau (QTP), including indigenous fishes. More monitoring and management of western mosquitofish should be conducted in the Eastern Himalayas to mitigate invasion risk and protect the native fish biodiversity from this exotic species.

Pseudemys concinna (River cooter) is native to the United States. Although the turtle is invasive to many countries around the world, successful breeding in the wild is confirmed only in the Iberian Peninsula. River cooters have been imported into the Republic of Korea, hereafter Korea, since early 2000s and sold nationwide. Due to discovery in the wild, they were designated as an invasive species in March 2020, and the import and trade of this turtle were banned. This paper reports two cases that serve as evidence for the successful settlement of the river cooter introduced in Korea. On June 27, 2019, a female P. concinna and her nest were found at a public park in Yangcheon-gu, Seoul, the Republic of Korea. Two out of 12 eggs were on the verge of hatching. On October 17, 2019, however, all eggs were found dead. On April 6, 2022, two hatchlings of P. concinna presumed to be born in 2021 were found in Geumho Reservoir, Jinju City. One of the hatchlings was captured on April 27, 2022. Successful breeding in the wild suggests that P. concinna has settled in Korea’s natural environment.

Alborán Island is located in the centre of the Alboran Sea in the Western Mediterranean, between the Iberian Peninsula and North Africa. Due to its geostrategic position and rich fishing grounds, this island has been frequently visited by humans throughout history from both coasts of the Alborán Sea, leading to the accidental introduction of many reptile species. However, during one field expedition a few specimens morphologically identified as Saurodactylus mauritanicus geckos were found at several areas of the island and considered as native to the region. This classification carried several nomenclature and conservation consequences to both species and Alborán Island. To clarify the taxonomic identification of the specimens found in Alborán and to evaluate its alien status in the island, we assessed its phylogenetic relationships among all Saurodactylus taxa under a mitochondrial genetic approach. We found that the sequenced specimen from Alborán, clusters with individuals of the S. fasciatus clade, instead of S. mauritanicus. Hence, this study does not support the proposed nomenclature change, neither the species nor the island’s conservation status based solely on S. fasciatus from Alborán.

Expanding the trade of tropical fruits in an increasingly globalized world increases the likelihood of unintentional importation of viable herpetofauna and their parasites from other countries and even continents, since the conditions for growing and transportation of fruits (humidity, temperature) can often be tolerated by exotic amphibians and reptiles. Here we describe our findings of two reptiles, Podarcis siculus campestris and P. ionicus (formerly P. tauricus ionicus), and an amphibian, Scinax ruber, in boxes of tropical fruits in Daugavpils city, Latvia, European Union. In our parasitological survey of S. ruber, we found two groups of endoparasites: nematoda (Physaloptera sp.) and trematoda (Travtrema aff. stenocotyle mtc.). In P. ionicus intestine we found acanthocephalan Centrorhynchus sp. larvae. All these parasites were detected in Latvia for the first time. The estimated minimal direct distance of the trans-oceanic relocation of S. ruber and its parasites from its natural distribution centre in Suriname to its finding place in Latvia exceeds 10 600 km.

In the Republic of Korea, the uninhabited Sasudo island is well known as a breeding ground for seabirds; however, it is seriously threatened by the predation of invasive rats. Here, we analyzed the mtDNA CYTB gene sequence to identify the species of invasive rats captured on Sasudo island from August 2015 to May 2016. The CYTB sequence of the three invasive rats on Sasudo island was 1048 bp long. BLAST analysis showed 99.81–100% homology with the R. norvegicus and a monophyletic pattern in the phylogenetic tree. These results indicate that the rats found on Sasudo island belong to the species R. norvegicus. This study is the first to provide accurate species information and explain the invasion of R. norvegicus on Sasudo island through genetic identification. We conclude that genetic species identification provides reliable information regarding invasive species. This information can be used as basic data for managing invasive species to protect island biological resources.