Gleditsia triacanthos (Leguminosae) is a deciduous tree native to the Eastern USA. The first invasive record of G. triacanthos in the Iberian Peninsula is here reported. The invaded area (Guadiamar river, southern Spain) is under a Csa climate type, which is an infrequent and unexpected type for that species to behave as invasive. The analysis of trunk perimeters and of the spatial distribution showed a net recruitment and an invasive trend throughout the temporary stretch of the river.

The various problems caused by invasive species have become more serious in recent years, and thus it is important to discuss their identifications and invasion processes. Phylogenetic and population genetic methods are effective tools for solving these problems. Some land snails, including the genus Macrochlamys, have invaded and established themselves worldwide as invasive species. In this study, we identified the species of Macrochlamys sp. from Japan and estimated their invasion pathways to Japan. Phylogenetic analysis showed that the Japanese snails were closely related to Macrochlamys indica from Bangladesh and West Bengal. Population genetic analysis also revealed that most of the Japanese snails were concentrated in single haplotype and were close in genetic distance. Detailed anatomical investigation of genitalia and oral organs showed morphological similarities between the Japanese and Bangladeshi snails, supporting the results of the phylogenetic analysis. These findings suggest that the Japanese Macrochlamys sp. is recognized as Macrochlamys indica and may have been introduced from the vicinity of Bangladesh and West Bengal and subsequently spread within Japan.

First reports of pheretimoid earthworms in Atlantic Canada, from a suburban site in south-central New Brunswick, are documented. Pheretimoids were present at high densities under hardwood cover, estimated at ~ several hundred per m^-2 in the small area sampled. Preliminary samples collected at the site in October 2021 suggest that Metaphire hilgendorfi, followed closely by Amynthas tokioensis, were dominant, while A. minimus was rare. The latter is the first report of A. minimus from Canada. Associated lumbricids, present in much smaller numbers and in descending order of abundance, included Lumbricus rubellus, Dendrobaena octaedra, and Aporrectodea tuberculata. We suggest that pheretimoid earthworms are probably more widespread in the Atlantic Canadian region than this first report would indicate. Further survey, supported by public education and reporting, will be required to assess the full ecological impact of invasive Asian pheretimoids in eastern Canada.

Aquatic ecosystems are under threat from nonindigenous species invasion. Fouling organisms on ship hulls are constantly in transit, posing a threat to recipient communities by reducing biodiversity and causing severe economic and public health impact. In the south of Iraq, a range expansion for the nonindigenous barnacle Amphibalanus subalbidus was recorded. On a West Asian scale, Shatt Al-Arab could be a hotspot for biological invasions in Iraq, since this river connects the Persian Gulf to inland waterbodies. Amphibalanus subalbidus could establish settlements in a variety of habitats due to its highly oligohaline distribution, which can withstand prolonged exposure to fresh water. Thus, a morphological consideration and their related distribution in the south of Iraq are discussed for this invasive species.

The Papahānaumokuākea Marine National Monument (PMNM) is one of the world’s largest marine protected areas and covers marine habitats as well as the islands and atolls of the Northwestern Hawaiian Islands. Despite its protected status, the biodiversity of the PMNM face several threats to its preservation, including the presence of introduced species. Given its history as a shipping and military outpost, Midway Atoll represents a potential entry point for introduced species to the PMNM. Thus, monitoring for new introduced species in Midway is of importance for the management and preservation of the PMNM. In this study, we use morphological and molecular approaches to confirm the presence of the coastal isopod Ligia exotica, a species of Asian origin that has been introduced to coastlines around the world, in Midway Atoll and thus the PMNM. The presence of L. exotica in Midway Atoll is of concern as islands of this marine monument harbor endemic species of Ligia isopods.

The little fire ant, Wasmannia auropunctata is an invasive species native to Central and South America. We report the establishment of this species in Taiwan, which is also the first confirmed population in the East Asian region. Little fire ants were found at two locations in central Taiwan, separated by approximately 30 km. Genetic and behavioral analyses indicated that the two populations both employ clonal reproduction and showed no aggression towards each other. Results of population genetic analyses indicate that the two populations are most likely derived from a common source population or genetically similar populations.

Invasive species are one of the main causes of biodiversity loss worldwide. As introduced, populations may increase in abundance and expand geographical range, so does the potential for negative impacts on native communities. As such, it is necessary to understand the processes driving range expansion, before a species becomes established in new areas. Through an investigation into capacity for population growth and range expansion of introduced populations of a non-native lizard, we aimed to demonstrate how multi-scale factors influence spatial spread, population growth, and invasion potential in introduced species. The Italian Wall Lizard (Podarcis siculus) was introduced multiple times to the United States with extant populations in California, Kansas, New Jersey, and New York. Recently, a single specimen was discovered in British Columbia, Canada, and unstudied populations are on Orcas Island and Missouri (USA). We used phylogenetic analysis of mtDNA sequences (cytb gene) of individuals sampled from these introduced populations and across the native range to identify potential source populations. Our phylogenetic analysis result with documentation of the introductions revealed that the Canadian individual is derived from the Tuscany clade (together with samples from Kansas and New York). The New Jersey population is likely from the Adriatic clade and the Californian one from Sicily. The Orcas Island and Missouri populations still require study. Consequently, humans are key drivers of the distribution of alien reptiles in North America, but the distributions are determined by a complex interplay between human activities, geographic factors and species features. Genetic evidence is essential for reliable biogeographic assessment of invasive species, particularly in systems with a long history of human influence.

Ladybird beetles (Coccinellidae) were collected at 11 sites on the island of Madeira from 4th to 10th of February 2020. Eight species non-indigenous to Madeira were recorded, and two of them, Olla v-nigrum and Cryptolaemus montrouzieri, have not previously been reported from the Madeira archipelago. This study also confirmed that Harmonia axyridis, a highly invasive species with an almost global range, has established on the island. According to the literature data and results of this study, 42 species of Coccinellidae have so far been documented to occur in the Madeira archipelago, including nine non-indigenous species of Afrotropical, Asiatic, Australian, and American origin. Comparison of available data on non-indigenous Coccinellidae recorded in different archipelagos of Macaronesia shows that Madeira has the richest fauna of those non-indigenous species. The percentage contribution of the non-native species to the fauna of Coccinellidae of different Macaronesian archipelagos ranges between 12% (Cape Verde) and 21% (Madeira) and is higher than that reported for the mainland areas in SW Europe (6.5–7%). This study supports the island susceptibility hypothesis.

While monitoring the invasive freshwater invertebrates in Romania, specimens of a previously unknown prawn were reported on social media (Facebook) to occur in the lower reaches of the Danube and Pruth rivers. First individuals, including ovigerous females, were captured at Galați in a floodplain pond of the Danube in August 2021 and kept in an aquarium by a local hobbyist until their release back in the same place. In November 2021, several other specimens were observed and photographed in the lower Pruth at Slobozia Mare (Republic of Moldova). One adult male was captured by a crayfish catcher in November 2021 on the Chilia arm of the Danube Delta at Ceatalchioi. There were already several reports of numerous individuals captured by local crayfish trappers in the lakes Ligheanca, Băclăneștii Mari and Fortuna in the Romanian Danube Delta in July 2022. All these individuals were identified as the oriental river prawn Macrobrachium nipponense. The invasion history of M. nipponense in the area is inferred based on currently available literature and social media sources.

Salvinia minima Baker (Salviniaceae) has been recorded for the first time in Africa. This South American native macrophyte is highly invasive and damaging, costing millions of dollars to control in the USA, and has the potential to invade many of southern Africa’s waterbodies. Field surveys have confirmed the presence of S. minima from four sites in South Africa, with the largest invasion occurring on the highly polluted Hartbeespoort Dam, north east of the country’s capital. Salvinia minima has been targeted for biological control in South Africa, using the weevil, Cyrtobagous salviniae, which is undergoing host specificity testing under quarantine conditions.