Aquatic plants are expanding their geographic distributions necessitating updated inventories that include evaluations of potential impacts on biodiversity, environmental services, and water management. This study describes the geographic distribution of native and non-native aquatic plants from 11 hydrological regions and basins of México, including 56 reservoirs, 14 lakes, two irrigation channels, two drainages, and one river. Forty-two aquatic plant species were recorded, of which eleven were non-native and invasive, and 31 were native. Of the native species, all but four are considered to have the potential to become invasive in novel habitats. The estimated percent surface coverage by different species of plants recorded in this survey ranged from 5% to 100% of the water bodies. Eichhornia crassipes (water hyacinth) was the most common, non-native species observed in the Mexican inland waters. This is the first report on the geographic distribution of invasive aquatic plants that affect biodiversity, water availability and uses in México.

Sampling campaigns associated with the ongoing PhyBiO project revealed the new presence of the benthic pinnate heterovalvar araphid diatom Licmophora normaniana. This species is considered cosmopolitan and is common on marine coasts. Based on literature searches, the following identification represents the first known occurrence in an inland mineral spring in the Siwa Oasis, the Western Desert of Egypt, and of this diatom species in mineral desert springs generally, or from any inland waterbody. The presence of L. normaniana was confirmed using light and scanning electron microscopy. Environmental variables (including major ions and metals) of this Saharan biotope were measured to characterize the habitat of this population. We hypothesize that the introduction of this marine species in the Siwa Oasis was related to fish farming activities carried out in the springhead by local inhabitants. We further hypothesize that the primary negative consequence of this invasion is likely to be the alteration of diatom community composition, with possible replacement of characteristic native taxa. Biological invasions place further pressure on spring habitats in oases, where they are affected by numerous growing human impacts, including global climatic changes. Therefore, legislation to protect these springs and enable sustainable and adaptive management, coupled with raised public awareness, is urgently needed to safeguard and conserve these unique biodiversity hotspots.

It is generally accepted that urbanisation is changing the composition of species, mostly in urban and surrounding areas, through intentional introduction. The South African National Status Report of 2017 on biological invasions has shown that there is a dearth of knowledge about the invasion status of many invasive alien species in many parts of the country, such as the critically threatened vegetation, Woodbush Granite Grassland (WGG) in Limpopo Province. Consequently, the present study investigated the status of alien plants species in WGG. A roadside survey was carried out in Haenertsburg Village and its vicinity. Roads were used as survey units, and the dumpsite was used as a high risk area. A total of 136 species were identified, belonging to 46 botanical families. This study report the occurrence of 72 species which are regulated by the South Africa’s National Environmental Management: Biodiversity Act (NEMBA, Act 10 of 2004). The present study found results significantly different from existing databases (χ² = 16.33473, p = .0001). Included in our list are alien species that need urgent eradication: Coreopsis lanceolata L., Cytisus scoparius (L.) Link, Iris pseudacorus L., Pueraria montana (Lour.) Merr, - and Rubus species as NEMBA category 1a species. Illegal dumping of agricultural waste was found to be one of the contributing factors to IAS in the area. Our study shows that Woodbush Granite Grassland is facing a new threat from invasive species.

Leucanthemum vulgare, Lam. (Asteraceae) (ox-eye daisy) is a perennial herb and an aggressive invader native to Eurasia. Today, the species is found in all continents except for Antarctica, and is an invasive in many countries. In this study, we present records of invading populations of Leucanthemum vulgare in the Limpopo province, South Africa, covering over 21.717 m² of critically endangered grassland. Management guidelines for Leucanthemum vulgare are provided.

The present study reports on the occurrence of Ipomoea hederifolia L. in South Africa. The established populations of Ipomoea hederifolia were detected in 2019 and 2020 in different locations in the Limpopo Province, with herbarium records showing at least four other localities in the country. Further work is now needed to determine the impact of Ipomoea hederifolia on native biota and agricultural production.

Verbena brasiliensis, the Brazilian Vervain, is a flowering plant species from Verbenaceae family. It is native to parts of South America, but has spread its range in recent times. During floristic surveys in Bartın province in northern Turkey, a new alien species for the country (Verbena brasiliensis, Verbenaceae) was found. Only two Verbena species were previously known from Turkey. We present an identification key and description of morphological characters of the species, as well as notes regarding the habitat where it was found.

The carnivorous pitcher plant Sarracenia purpurea has been introduced across Europe from North America. Thus far, whether the inquiline species intimately associated with S. purpurea have also been introduced had not been studied. Sarraceniopus gibsoni is the obligate mite species found in S. purpurea and is ubiquitous within the pitchers in North America. Three sites in Britain and Ireland were sampled. Two of the three sites were confirmed to support S. gibsoni populations, one site in Ireland and one in England. The presence of S. gibsoni suggests that living plants of S. purpurea had been introduced to the sites hosting mite populations.

The invasive taro root aphid, Patchiella reaumuri (Kaltenbach) (Hemiptera: Aphididae) of Western Palearctic origin, is a highly devastating pest of taro, Colocasia esculenta (L.) Schott (Family: Araceae) in the Pacific region and Europe. Consequently, P. reaumuri is considered as an important quarantine pest for taro growing regions. We detected for the first time the infestation of P. reaumuri causing 34.3% yield loss in the field and 62.4% loss in storage. This is the first taxonomically confirmed record of P. reaumuri from Asia and a global first record of its damage in storage. The northeast region of India, being a part of primary centre of origin of taro, is very rich in diversity of taro, where several traditional landraces are important dietary components of the residents, therefore, the invasion of destructive P. reaumuri may wreak havoc, if not timely diagnosed and managed. This study focussed on the detection of P. reaumuri in a new invaded region, on reporting losses caused by P. reaumuri in its new habitat, and the presentation of an illustrative morphological diagnostic and DNA barcode for its diagnosis at quarantine ports.

Boxwood Buxus sempervirens L. is an ornamental bush very often found in utilitarian greenery. Boxwood is a host for several important mite and insect pests of which the box tree moth Cydalima perspectalis (Walker, 1859) (Lepidoptera: Crambidae) is currently the greatest threat to B. sempervirens in Poland. Uncontrolled feeding of caterpillars of this moth leads to complete defoliation of the affected plants, which results in rapid and often massive dying of boxwood bushes. The aim of the study was to assess its biology, harmfulness and analyze the expansion and extent of the box tree moth in southeastern Poland in the last five years. The deepening problem of the rapid and uncontrolled expansion of the box tree moth in the Podkarpackie Province was caused by the lack of a methodology for monitoring and controlling the population of this species and the lack of registered plant protection products dedicated to its control.

We report the occurrence of Brachyplatys subaeneus (Westwood, 1837) on a new host plant species: the leguminose Macroptilium longepedunculatum. We discovered the bugs in the mouth of the river San Juan in Coiba National Park in Panama. We present the morphological and barcode species level identification. This insect pest normally attacks plants of economic importance within cultivated habitats and our report possibly highlights for the first time the ability of B. subaeneus to invade natural habitats.

Asian seed beetles of the genus Megabruchidius have been recorded recently in many European countries. Our contribution serves to formally report the first records of M. dorsalis in Bosnia and Herzegovina, Montenegro and Albania and the first record of M. tonkineus in Montenegro, all found in 2021. Both species develop inside the hard seeds of the ornamental tree Gleditsia triacanthos. Mature G. triacanthos pods were collected from the ground in urban parks of Nikšić and Podgorica (Montenegro) and Tirana (Albania) in July 2021, and Banja Luka (Bosnia and Herzegovina) in August 2021. Fully developed beetles were recorded after two weeks. dorsalis emerged from the pods collected in all locations, while M. tonkineus was reared only from the pods collected in Podgorica. Because in Podgorica both species were found in the same pods, this also represents confirmation that in some locations these species do co-exist. Overall, M. dorsalis was more widespread and abundant.

Synanthropic silverfish species have spread over Europe as invaders in recent years. This paper reports the first occurrence of synanthropic silverfish Ctenolepisma calvum in the Czech Republic. Established populations of the species were revealed at two localities in Prague. At both sites, C. calvum occurred inside the buildings with room temperatures of 23.3–28.3 °C and moderate humidity 32.6–55.8%. From this point of view, our observations indicate that the climate restrictions suggested for Lepisma saccharinum and Thermobia domestica may not be effective against C. calvum. Thus, its suitable management is challenging for the future. This study also summarizes the available data on C. calvum distribution from the literature, social platforms and invasive species databases, which pointed out that only little is known about C. calvum and the species seems to be either under-recorded or rapidly spreading throughout Europe. In light of this, further monitoring, as well as risk assessment of this silverfish species, is highly needed.

The dwarf honeybee Apis florea Fabricius, 1787, an invasive alien species, has been rapidly expanding in Kaohsiung city of southern Taiwan since 2017. The aim of our study was to understand the expansion and status of A. florea populations by: 1. Removing nests and assessing their development, and measuring the phenological activities. 2. Sequencing DNA to determine origins of invasion. Our results show that A. florea prefers to use anthropogenic sites and concealed places for nesting. We conclude that residential areas serve as refugia for A. florea, as they provide ample nesting substrate structurally similar to that in their native range and are markedly cooler, allowing them to adapt to a vastly different climate. DNA sequencing results suggest a single origin of A. florea invasion in Taiwan.

More than half of National Parks in the United States report the presence of invasive animals. Here we report a checklist of non-native aquatic fauna at Lake Mead National Recreation Area, Nevada, with the earliest reported sighting in 1940. Seventy-two species of non-native aquatic fauna were found representing six taxonomic groups. 41 (57%) are established, 9 (13%) are either eradicated or failed, and the status of 19 species (26%) is unknown. This comprehensive species list represents a preliminary step in developing monitoring programs for invasive species currently found within Lakes Mead and Mohave. It will also help inform the development of early detection and rapid response activities and monitoring to safeguard the park from future invasions.

Melanoides tuberculata is a well-known invasive, freshwater snail and intermediate host for many species of parasitic trematodes. Despite being well established in Florida’s freshwater systems, little work has been conducted to document the associated trematodes of the snails. Live snails were collected from 11 sites from 25 locations sampled across the state of Florida, USA of which individuals from six sites were found to be infected with trematodes. Gross morphological characters and phylogenetic analysis using 18S rRNA and ITS2 gene regions, were used to identify these trematode taxa. Snails infected with the gill flukes, Centrocestus formosanus and Haplorchis pumilio (Heterophyidae) were found at two and four sites, respectively. While C. formosanus has been documented in this snail species in Florida, H. pumilio has not been documented in Florida before this study. The eye fluke, Philophthalmus sp. (Philophthalmidae) was found in two sites. This parasite was previously reported in Florida in birds but not in any snail hosts. An unidentifiable species of kidney fluke, Renicolidae sp., and an unidentifiable species of bat fluke, Lecithodendriidae sp., were found in one site each. Both Renicolidae sp. and Lecithodendriidae sp. are new North American records of trematodes infecting M. tuberculata, but whether they are they are of native or invasive origin is unknown. These new records of trematode taxa infecting M. tuberculata in Florida emphasizes the critical need for monitoring of invasive snails and their associated parasites.

This contribution presents the first established population of the Chinese pond mussel Sinanodonta woodiana (Lea, 1834) (Bivalvia: Unionidae) in Greece. Previous single reports from rivers Axios and Evros need further investigation. Chinese pond mussels were collected in Lake Pamvotida (= Pamvotis or Ioannina) during a mussel field expedition in October 2020. This alien species was first detected in 2006 in a fishpond adjacent to the lake from where it possibly dispersed. The species is now widespread and abundant throughout the lake and is most possibly displacing a genetically unique population of Anodonta cygnea endemic to the lake. Species identification was confirmed with genetic cytochrome oxidase c subunit I (COI) gene barcoding sequences. A single COI haplotype was retrieved which is shared by the vast of majority of the specimens sequenced from the invaded range in Europe. Monitoring of S. woodiana presence and abundance should be widely conducted and special attention and collaboration with fish farms is urgently required to prevent its dispersal to other freshwater ecosystems.

The quagga mussel Dreissena rostriformis bugensis was identified in a horizon scan of species likely to arrive in Ireland. We report on the first records of this dreissenid from two lakes, a reservoir and interconnecting navigable river sections on Ireland’s largest river, the Shannon, during July 2021. The abundance in Lough Ree was greater than in the larger downstream lake of Lough Derg. Specimens occurred to depths of 24 m and 32 m in each of these lakes respectively. Highest densities were in the southern region of Lough Ree attached to piles supporting floating pontoons and quay walls. Here D. r. bugensis outnumbered the D. polymorpha present. It was present at lower densities downstream to Lough Derg and the Parteen Reservoir. This species has a wide range of colour morphs from a pale yellow to dark concentric or longitudinal banding.

The current study reports on the second record of a wild population of the invasive alien red swamp crayfish Procambarus clarkii in South Africa following a report from Mimosa Dam in the Free State Province. Sampling for crayfish was conducted over an 18 month period (June 2018 to November 2019) using various methods in order to determine the extent of the invasion as well as to obtain preliminary information on the population structure within Mimosa Dam. Additionally, a gear and bait comparison experiment was conducted to determine their efficiency in mechanical removal of the P. clarkii. Three sampling approaches were compared: promar collapsible traps baited with either dog food or fish; and rectangular traps baited with fish, all which have been historically used in crayfish surveys. A total of 1901 crayfish with a total biomass of 27.32 kg were caught during the study and 65% of those were juveniles. The female to male sex ratio (1:1.2) in Mimosa Dam was skewed towards males. Fish head bait provided a higher catch per unit effort (CPUE) (1.2 ± 0.57 and 0.71 ± 0.08 for rectangular and promar traps, respectively) which was significantly higher than that of the dog food bait (0.14 ± 0.04). The fish bait should hence be optimised for intensive population suppression. Complete eradication of P. clarkii is virtually impossible, as shown by this study, but population suppression can be concentrated on months of crayfish population surges to minimise associated impacts on native biota.

The alien shrimp Macrobrachium nipponense (De Haan, 1849 [in De Haan, 1833–1850]), oriental river prawn has been identified in the water bodies of the Ukrainian part of the Danube Delta for the first time. Diagnosis of the species is based on measurements of 35 specimens. Characteristic features: the dorsal side of rostrum armed by 12–13 teeth, with feathery setae between them, 3 (rarely 2) teeth located on the ventral side of rostrum. During 2019–2020, the freshwater shrimp, M. nipponense, has become a common element of the benthic fauna of the Kiliya arm of the Danube River. It is supported by regular registrations of numerous shrimp aggregations in different parts of the arm (from the 32nd to the 80th km of the main stream) since the summer of 2019. The record of this alien shrimp species potentially confirms its introduction from other water bodies of the North-Western Black Sea Coastal Area to the Danube Delta by the natural dispersion or the unauthorized introduction. Although the known records suggest an accidental introduction of this species into the area close to the lakes of the Lower Danube area, both hypotheses require further investigation and approbation.

The first occurrence of Diadema setosum in the southern Mediterranean waters is recorded from the shores of Libya and Egypt, through the input by citizens’ science. The expansion of this invasive sea urchin in the Mediterranean basin is briefly discussed.

The occurrence of Chrysaora pacifica (Goette, 1886) (Cnidaria, Scyphozoa) is reported from most Japanese and Korean coastal waters. This is the first record of the alien jellyfish Chrysaora pacifica from the Liaodong Bay, Bohai Sea, China. Eight specimens of Chrysaora sp. were collected. Based on the evidence from morphology (bell, size, umbrella pattern, number of tentacles, and lappets) and further molecular analysis (mitochondrial DNA sequences comparison), we identified the Chrysaora sp. jellyfish as Chrysaora pacifica which belonged to Cnidaria, Scyphozoa. The distribution of C. pacifica in the Bohai Sea is currently unknown, however, there is a high potential risk for the spread of this species to the whole Bohai Sea by the ocean currents circulation system. As C. pacifica is a bloom-forming species, we recommend further work to assess the distribution of this species and its impact on the local fauna and flora.

İskenderun Bay is a hotspot for bioinvasions in the Mediterranean Sea, where alien species are frequently introduced, easily settle, and therefore, can often be encountered. The small-sized invasive copepod Oithona davisae (Ferrari and Orsi, 1984) has rapidly spread in several ecosystems worldwide, including the Black Sea, Wadden Sea, Marmara Sea, Adriatic Sea, and Aegean Sea, becoming an integral part of the pelagic communities there. Here, we report O. davisae in İskenderun Bay, in the north-eastern part of the Mediterranean Sea, and provide information on its spatiotemporal variation and assess its potential impact on the seasonal abundance and biomass of the mesozooplankton community, at present and in the near future. Zooplankton abundance and biomass were at their lowest levels in winter (1066 ± 313 ind. m^-3, 1.9 ± 0.8 mg m^-3) and highest in spring (7738 ± 1583 ind. m^-3, 18.5 ± 5.8 mg m^-3). However, the relative abundance of oithonid copepods was highest during the winter (35.7 ± 10%). The proportion of copepodites in the oithonid assemblage was high in spring (72.5 ± 9.3%), summer (72.7 ± 13.3%) and winter (68.5 ± 3.6%) but the relative abundance of male oithonids remained low across all seasons. Oithona davisae was observed only in the autumn, in abundances of 8.4 to 12.6 ind. m^-3. These low abundances could be attributed to the new arrival of this species and the relatively large mesh size used in this study (200 µm). Nevertheless, the successful introduction and assimilation into other mesozooplankton communities elsewhere, rapid adaptability and wide tolerance to environmental conditions of O. davisae, suggest that this species may become a dominant part of the zooplankton community across the Levantine Basin in the very near future.

The occurrence of the exotic Atlantic blue crab Callinectes sapidus Rathbun, 1896 (Crustacea: Decapoda: Portunidae) is reported for the first time from the Moroccan Atlantic coast. Working with local fishermen, we gathered 160 records of the Atlantic blue crab from several estuarine, coastal and marine areas, in the period between June and August 2021. These new records confirm its establishment in the Atlantic coasts of North Africa, suggesting a southern range expansion. These findings, likely exacerbated by growing populations along the Atlantic coast of Morocco and temperate coastal waters, provide new insights into the invasion dynamics of this species in the northeast Atlantic Ocean.

The invasive portunid species Callinectes sapidus is hereby recorded for the first time from Maltese waters, thus updating the known distribution of this decapod of Atlantic origin within the Mediterranean. Potential introduction pathways of the species to Maltese waters are discussed.

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.

Chinese sleeper (Perccottus glenii) is one of the most successful invasive fish species, spreading rapidly to colonize a wide range of ecosystem types, from lentic oxbows to large rivers and freshwater lakes. Previously, only a single individual of P. glenii has been recorded from Croatian waters, in the Sava River catchment. This study reports the presence of additional record and the first population of P. glenii in the Croatian part of the Drava River. During a field survey, eight individuals (n = 8) of P. glenii were collected from a shallow and overgrown freshwater oxbow in the Drava River flood zone, within a NATURA 2000 protected site. Since several individuals were within the mature size class (i.e., larger than 55 mm standard length), the results emphasize the importance of early confirmation of the presence of this invasive species, and the need for comprehensive biological surveillance of the Drava River and similar floodplain habitats, especially downstream of this collection site. Two hypotheses (north and south) explaining the arrival of Chinese sleeper into the Croatian part of Drava River are proposed. Semi-closed oxbows, such as the present one, could represent a suitable ecosystem for detailed in situ experiments on P. glenii ecology and migration patterns.

Some alien invasive fish species, such as, for example, the brown bullhead Ameiurus nebulosus can be the dominant component of the native fish community. The aim of this study was to determine the abundance and size structure of A. nebulosus and its contribution to the ichthyofauna of mesotrophic Lake Jegocinek (Masurian Lake District, north-eastern Poland). In August 2020, a total of 723 individuals of A. nebulosus were caught by benthic and pelagic Nordic multi-mesh gillnets. This alien species probably originated from an illegal release into the lake. Total length and body weight of A. nebulosus ranged from 77 to 248 mm (mean of 146 ± 55 mm) and from 4.2 to 241.3 g (mean of 57.0 ± 54.9 g), respectively. The population of A. nebulosus was mainly represented by two size groups. The first group was composed of small-sized specimens (below 100 mm and < 10.0 g), while the second group consisted of large individuals (above 180 mm and 70.0 – 110.0 g). This indicates that the population in this lake has a multigenerational structure. Our study showed that A. nebulosus accounted for 19% of the total numbers and 21% of the total biomass of all caught fish. The total length and body weight did not differ significantly between the littoral and pelagic zones. Relative numbers (NPUE) were lower in the littoral than in the pelagic zone, while relative biomass (WPUE) was very similar in both zones. Although the values of the coefficient of condition were almost identical in the littoral and pelagic zones, it seems that the near-shore waters offer more favourable environmental conditions for the growth of A. nebulosus than deeper open waters of a lake.

Non-native species have a significant negative impact on the environment where they have been introduced, and amphibians are among some of worse invasives. All known amphibian introductions are linked to human activities, generally in relation with pest control or food provisioning. This is the case of all amphibians on Ulleung Island, which were originally and mistakenly thought to be “reintroduced” after extirpation, or introduced for unrealised purposes such as food provisioning and pest-control. We conducted call and visual encounter surveys in all valleys of Ulleung Island, Republic of Korea, in April and May 2021 to detect the presence of amphibian species. The call surveys and subsequent call analyses revealed the presence of two geographically independent populations of Pelophylax nigromaculatus, and encounter surveys resulted in the sampling of Rana tadpoles identified as Rana huanrenensis with molecular tools. These results highlight the presence of these two species at low density on this island, but do not provide data on the impact of their presence.

An increasing number of thermophilic invasive species are spreading and becoming naturalized in Eastern Europe, at least partially due to recent climate change. This can be exemplified by current expansion of the red-eared slider, Trachemys scripta, in Latvia and Ukraine. We collected 44 records of the species in Latvia and 79 in Ukraine. Two of the three subspecies have been found – T. s. elegans and T. s. scripta. In both countries courtship behavior and egg-laying have been observed. Individuals successfully surviving the winter in the wild have been recorded. Due to climate change, it is likely that this species has the potential to establish itself in Latvia and Ukraine.

The Caribbean islands are becoming a hotspot for the spread of non-native reptiles. Consistent with this trend, we provide the first documentation of three new lizard species discovered on Aruba, Anolis gingivinus (Cope, 1864), Anolis cristatellus (Duméril and Bibron, 1837), and Hemidactylus frenatus (Duméril and Bibron, 1836). In addition, we provide an updated distribution on Aruba for a previously introduced lizard species, Anolis porcatus (Gray, 1840). All four species were identified phenotypically in the field and identifications were confirmed with genetics. Like most non-native lizards in the Caribbean, they tend to use anthropogenic habitats, and their impacts on Aruba’s resident species are not known.