EU strengthens biosecurity: 26 new alien species added to Union concern list

The European Union has taken a significant step in strengthening its biosecurity by extending the list of invasive alien species (IAS) of Union concern, as mandated by Regulation (EU) No 1143/2014 on the prevention and management of the introduction and spread of invasive alien species. This crucial update adds a substantial number of new species, bringing the total from 88 to 114, marking a critical step in the EU's ongoing battle against biodiversity loss and economic damage caused by non-native organisms. Additionally the species clarifies some important taxonomic issues which will prevent confusion on the identification of a few species, among which the group of kingsnakes (Lampropeltis getula).

Formalized by Commission Implementing Regulation (EU) 2025/1422 of 17 July 2025, this expansion is particularly notable for its inclusion of challenging species across various fronts. It now extends further into marine environments, an area notoriously difficult to manage. Simultaneously, it also lists high-profile species like the American mink (Neogale vison) and the North American beaver (Castor canadensis), despite the significant economic interests characterising the former and the complex management challenges posed by the latter. While such listings trigger strict restrictions on activities like import, sale, breeding, and impose obligations for early detection and rapid eradication, the two years deferral of the mink and beaver's effective listing date demonstrates the Regulation's flexibility in meeting the needs of relevant stakeholders.

American mink (Neogale vison) farm © Photo: Riccardo Scalera

For the majority of species, inclusion on the Union list means immediate enforcement of stringent measures. The newly added species significantly broaden the scope of the EU's IAS management across various taxonomic groups:

Terrestrial plants: this update sees the addition of new plant genera like black wattle (Acacia mearnsii), expanding on existing Acacia species such as golden wreath wattle (Acacia saligna). Other new terrestrial plants include paper mulberry (Broussonetia papyrifera) and cape ivy (Delairea odorata). Critically, a complex of highly invasive knotweeds – Japanese knotweed (Reynoutria japonica), bohemian knotweed (Reynoutria x bohemica), and giant knotweed (Reynoutria sachalinensis) – are now collectively recognised, joining the previously listed Himalayan knotweed (Koenigia polystachya), underscoring the severe threat posed by this group. These new additions complement a substantial number of other terrestrial invasive plants already listed, including various hogweeds, grasses, and climbing vines.

Terrestrial birds: the list expands its avian representation with new bird species. The crested myna (Acridotheres cristatellus) joins the previously listed common myna (Acridotheres tristis), while the red-whiskered bulbul (Pycnonotus jocosus) adds another bulbul species alongside the red-vented bulbul (Pycnonotus cafer). These new avian invaders enhance the list's coverage of threats posed by other introduced bird populations, which includes species such as the Egyptian goose (Alopochen aegyptiacus) and ruddy duck (Oxyura jamaicensis).

Terrestrial mammals: beyond the deferred American mink and North American beaver, the list now includes the sika deer (Cervus nippon), joining the existing chital (Axis axis) and muntjac deer (Muntiacus reevesi), further addressing the impacts of non-native deer populations. The overall mammalian category on the list is now more comprehensive, covering a diverse array of other mammals, e.g. rodents, carnivores, and ungulates, already established in the Union, among which the coypu (Myocastor coypus) and the raccoon dog (Nyctereutes procyonoides).

Terrestrial invertebrates: this group sees a significant increase in attention. New types of predatory flatworms are added, including the kew worm (Bipalium kewense), and two species of New Guinea flatworm (Obama nungara and Platydemus manokwari), which join the previously listed New Zealand flatworm (Arthurdendyus triangulatus). The list also expands its invasive ant coverage with the Asian needle ant (Brachyponera chinensis), complementing existing fire ant species. The formidable Asian giant hornet (Vespa mandarinia) is also added, joining the previously listed Asian hornet (Vespa velutina) as a critical concern for pollinators.

Freshwater species: aquatic environments see a substantial increase in listed threats. New crayfish like the common yabby (Cherax destructor) and calico crayfish (Faxonius immunis) join an already extensive list of invasive crayfish. Several new invasive snails, including the Chinese mystery snail (Cipangopaludina chinensis) and giant ramshorn snail (Marisa cornuaretis), are added. The aquatic plant New Zealand pigmyweed (Crassula helmsii) and two new fish species, the oriental weatherfish (Misgurnus anguillicaudatus) and stripe weatherfish (Misgurnus bipartitus), also reflect a broadened focus on freshwater ecosystems. These new additions complement a comprehensive array of other existing freshwater fish, but also invertebrates, aquatic plants, and even amphibians and reptiles already on the list, demonstrating a holistic approach to aquatic biosecurity.

Marine species: building on the broad scope introduced, the expansion of the union list into marine environments remains a highly significant development. Given the notorious difficulty in managing alien species in marine settings and past reluctance from Member States to include them, the current update represents a considerable success. These additions now include the Northern Pacific seastar (Asterias amurensis), the dwarf surf clam (Mulinia lateralis), and Japanese eelgrass (Nanozostera japonica). These species join the previously listed marine algae, brown seaweed (Rugulopteryx okamurae), further demonstrating a growing recognition of invasive alien species impacts in seas and coastal areas.

Japanese knotweed (Reynoutria japonica) © Photo: Riccardo Scalera

This significant expansion underscores the EU's proactive commitment to biodiversity conservation. Member States must now implement robust surveillance for early detection, develop rapid eradication plans for new outbreaks, and establish effective management strategies for already widespread species. Public awareness and stakeholder engagement will remain crucial for successful implementation. This growing list is a vital tool to protect Europe's natural heritage against the escalating threats posed by invasive alien species, building on the proven effectiveness of the legislation as documented in the recent scientific paper by Canelles and colleagues Policies slow biological invasions in Europe, but legacies still matter. 

Furthermore, as highlighted during the 17th meeting of the Scientific Forum—the Regulation's advisory body of expert representatives from EU Member States—the Commission is actively preparing for future updates., with ongoing risk assessments for species such as the Asian jumping worm (Amynthas agrestis), Amazon frogbit (Hydrocharis laevigata), African boxthorn (Lycium ferocissimum), Amur river clam (Potamocorbula amurensis), white river crayfish (Procambarus acutus), Australian eelgrass (Vallisneria australis), cruel climber (Araujia sericifera), red shiner (Cyprinella lutrensis), a red alga (Gracilaria salicornia), giant East African snail (Lissachatina fulica), Dabry's weatherfish (Misgurnus dabryanus), Chinese softshell turtle (Pelodiscus sinensis), Canadian and giant goldenrod (Solidago canadensis and Solidago gigantea), and American red squirrel (Tamiasciurus hudsonicus) being thoroughly checked for compliance with the Regulation's criteria to identify additional species that qualify for listing, initiating discussions with Member States accordingly.

The Italian wall lizard: a conservation tale of a successful invader

If I could return as an animal, I'd like to be a lizard—an Italian wall lizard, you bet! Known to scientists as Podarcis siculus, this miniature, speedy dart of green is one of the world's most thriving and adaptable lizard species, and also a remarkably successful invader. Many introduced populations are now found far beyond their native range, which largely coincides with the Italian peninsula. Their global spread is often facilitated by humans, whether intentionally as pets or accidentally as hitchhikers on cars and trains. They can also be transported as contaminants alongside goods like building stones or nursery plants, particularly olive trees. Even the movement of Italian troops during the Spanish Civil War played a role in their introduction to Spain. But, as is often the case with alien species, once established outside their native range, they can quickly become a disruptive visitor that threatens local wildlife. Not surprisingly, some introduced populations of Italian wall lizards have been receiving increasing attention in recent years. A small population in Athens, Greece, was indeed eradicated a few years ago (mostly with the help of stray cats, for once a welcome ally of conservation biologists). Similarly, a few individuals were promptly removed at an early stage of introduction in Buckinghamshire, UK, and La Rioja, Spain.

Italian wall lizard introduced in Corsica
© Photo: Riccardo Scalera

However, the most interesting project targeting Italian wall lizards is taking place in the Aeolian archipelago in Sicily, Italy. The Aeolian Islands are a fascinating, arid group of small islands and rocks that emerged from volcanic activity in a beautiful corner of the Mediterranean Sea some 500 000 years ago. Here, the endemic Aeolian lizard (Podarcis raffonei) thrived until the introduction of the Italian wall lizard. The endemic species is now confined to three small rocky islets—Strombolicchio, La Canna, and Scoglio Faraglione—and a very small stretch of land on Vulcano Island, where the progressive expansion of the Italian wall lizard has cornered the remnant population. To combat this decline, expert researchers from a number of institutions, led by Roma Tre University, have launched the project LIFE EOLIZARD, co-funded by the European Commission, with many other partners including L'Aquila University, the Rome zoo (Bioparco), CNR and Triton.

A view to the Aeolian archipelago from Lisca Bianca
© Photo: Riccardo Scalera 

This ambitious project, aimed at halting and reversing the decline of this unique lizard, is structured around three main pillars: a) removing a threat to an endangered species, b) captive breeding of the endangered species, and c) reintroducing the endangered species. The introduced populations of Italian wall lizard on the two small islets of Lisca Bianca or Bottaro will be completely removed to turn them into a sanctuary for the reintroduction of the endemic Aeolian lizard. In parallel, Aeolian lizards are being successfully reproduced at both the Rome zoo (Bioparco) and a dedicated breeding center on Salina Island, making the release of hundreds of new lizards possible for recovery purposes. In this sense, EOLIZARD is a truly unique project that integrates the removal of an alien species with the reintroduction of a captive-bred population facing imminent extinction. This combination of measures is expected to increase the global population size by up to 140%, thus offering an unparalleled opportunity for the endangered Aeolian lizard to significantly boost its chances of survival. It is also worth mentioning that, in consideration of the human dimension, the invasive alien lizards are not killed but relocated to a nearby island where genetic analysis shows a sibling population already exists: thousands of little lizards will be gently captured by trained experts luring them into safe traps with some sweet juice, then quickly transported to the verdant island of Panarea and released into suitable habitats. This humane approach is one of the project's most innovative features.

Aeolian lizard captive bred at the Rome zoo (Bioparco)
© Photo: Riccardo Scalera

In a nutshell, EOLIZARD is exceptional because it operates as a living laboratory. This allows researchers to explore the ecological and evolutionary dynamics of both species and their ecosystems, including their relationship with human activity. Furthermore, comprehensive genetic analysis and health screenings performed on all animals provide a unique opportunity to understand population origins and the emergence of diseases, including potential zoonoses. The global significance of these efforts was widely recognized at an international workshop held in early June 2025 in Malfa, Salina Island, where world experts convened to share experiences on managing alien lizards and to discuss ideas for future research and collaboration. Insights shared at the workshop, drawing from a global dataset on lizard management, highlighted a critical hurdle: the lack of comprehensive reporting on management projects. 

EOLIZARD workshop participant
© Photo courtesy of Massimo Recupito (Triton)

Globally, approximately 20 species of invasive alien lizards are currently under some form of management, as highlighted at the EOLIZARD workshop. In Europe alone, where 50-70 species have been introduced or translocated outside their natural range within the region, the primary challenge with invasive lizards often comes from its own native Podarcis species. The Italian wall lizard for example is a remarkably successful and widespread invader, with established populations across much of Europe and beyond, including in Spain, Portugal, France, Switzerland, Greece, Croatia, Albania, Montenegro, Romania, Poland, Germany, Turkey, Tunisia, Libya, Azerbaijan, and the USA. The workshop's outcome was a clear call to action: we must develop effective methods for rapidly detecting and removing invasive lizard threats and, most importantly, implement measures to protect native species. In this context, the importance of the management and research activities carried out within the EOLIZARD project cannot be overstated. Never before has such an ambitious project been designed for a small lizard, neither in terms of the target alien population's size nor the area to be cleared. However, the project isn't without its risks. The complete removal of alien lizards could be quite challenging, especially when targeting the smartest or luckiest survivors, including newborns that may have escaped initial control efforts. Nevertheless, EOLIZARD has the potential to be a model for replication in many other areas.

This is a concrete example of the European Commission's conservation efforts. The Commission's approach is twofold: it aims to facilitate overall policy for alien species while also guiding local action. It achieves this by specifically funding innovative pilot, demonstration, and best practice projects through the LIFE programme, with the goal of encouraging beneficiaries to actively replicate and scale up the results. Furthermore, these efforts align with previous initiatives, such as the detailed management note for the Italian wall lizard. This note, also made for a number of other species, serves as an example of the measures needed to address threats from species that are native to some parts of the EU but invasive in others. These resources provide practitioners with crucial information on prevention, surveillance, rapid eradication, and long-term management. While the LIFE EOLIZARD project and the European Commission's mobilized resources are vital, the workshop's outcomes were clear: we must urgently improve data sharing, foster innovation in management techniques, and collectively raise the priority of addressing the subtle yet significant threat posed by invasive alien lizards. 

In the meantime, without stricter biosecurity measures, the Italian wall lizard will inevitably continue its global expansion. The lizard not only possesses all the ecological traits of a successful invader but is also actively supported by humans from around the world who enjoy having them sunbathing in their yards. So, as a take-home message, if you love Italian wall lizards as I do, don't take them with you abroad. Instead, just enjoy a visit to the Italian peninsula. You'll see plenty of them there and bring home great memories too!