The critical nexus: One Health and biological invasions

The health of human beings, animals, and natural ecosystems is fundamentally intertwined. Historically, a persistent ambiguity between the generic concept of "environment" and the functional reality of "ecosystems" obscured how ecological degradation directly drives disease emergence. This conceptual gap was recently clarified by the One Health High-Level Expert Panel (OHHLEP), which formally integrated the term ecosystems into the foundational definition of One Health, underscoring that safeguarding global health depends not merely on protecting abstract surroundings, but on preserving intact, functioning ecological networks.

Among the key drivers of ecological disruption, biological invasions - the introduction and spread of alien species into new environments - present a uniquely complex challenge. Yet, in global health discourse, this phenomenon is frequently reduced to a brief, superficial mention to "globalisation" without examining its specific drivers, pathways, and ecological consequences. Furthermore, biological invasions are often assumed to be already covered under regulations targeting the wildlife trade. However, these two phenomena are fundamentally distinct, and biological invasions carry a far more insidious epidemiological risk. While the wildlife trade focuses on the commerce and transport of animals, a biological invasion presupposes the actual release and establishment of an alien vector or host directly into the wild. Once introduced, these species can disseminate novel pathogens into native populations and surrounding habitats, a biological spillover that can persist indefinitely even if the invasive alien species itself is subsequently eradicated. Despite this irreversible threat, biological invasions remain largely disregarded in global health agendas. Virtually all biological invasions alter epidemiological dynamics by introducing new vectors and hosts that interact with native species in highly complex and unpredictable ways.

A foundational milestone in acknowledging this threat was the Council of Europe's Report on alien pathogens and pathogens spread by invasive alien species in Europe, prepared for the Bern Convention. This work brought to light a critical blind spot in modern health strategies: pathogens affecting wild species. Because wild animals and plants often lack direct agricultural or commercial value, the pathogens they harbor are largely invisible to official health surveillance systems and legislation. To bridge this dangerous gap, the Standing Committee of the Council of Europe adopted Recommendation No. 215 (2022), calling on nations to implement targeted surveillance, strict biosecurity protocols, and predictive tools to anticipate incoming disease risks before they escalate into widespread emergencies, particularly across human-wildlife interfaces.

Screening for pathogens in snakes handled during a
religious procession in Italy © Photo: Riccardo Scalera

Building upon these international efforts, an official study presented at the United Nations Biodiversity Conference (CBD COP16) held in 2024 in Cali, Colombia, titled Study on how approaches for the prevention, control, and management of invasive alien species may be usefully applied to biological invasions of pathogenic agents, in particular zoonotic pathogens (document CBD/COP/16/INF/28), formally recognized the pivotal role of biological invasions within disease dynamics. This vital connection was subsequently reaffirmed in the same year during the G7 discussions held in Rome, emphasising that addressing invasive alien species through a One Health lens is a global priority. When invasive alien species disrupt ecosystems, they weaken the natural ecological barriers that keep diseases in check, creating ideal conditions for alien pathogens to multiply and spill over into other species. To operationalise these principles, emerging global networks like WildHealth are bridging the gap between field biologists, disease experts, and policymakers to turn scientific warnings into practical ecosystem management.

Information board explaining virus transmission and
protective equipment in Japan © Photo: Riccardo Scalera 

Ultimately, moving beyond generic generalisations requires genuine cross-sectoral collaboration. Directly involving experts from diverse disciplines (such as invasion biologists, ecologists, veterinarians, botanists, physicians, social scientists and policymakers) in formulating concrete policies is essential to translate a fully realised One Health approach from theory into practice. Integrating the management of biological invasions into global health frameworks reveals clear and powerful synergies. By sharing surveillance tools, early warning networks, and rapid response mechanisms, nations can prevent both biological invasions and potential pandemics simultaneously, optimising resources and avoiding administrative duplication. Controlling invasive species that act as disease hosts or vectors directly disrupts transmission pathways, while restoring natural ecosystems reinforces structural integrity and reduces spillover risks. Biological invasions and emerging diseases are two sides of the same coin. Bridging the divide between ecosystem science and public health is an indispensable step toward safeguarding our collective future.

How to build a comprehensive invasive species strategy: bridging policy and practice

Biological invasions represent one of the main drivers of biodiversity loss globally. they act in synergy with other severe threats, such as climate change, habitat destruction and modification driven by agriculture, wildfires, and urbanization, as well as the international wildlife trade. This compounding crisis has a massive impact not only on natural ecosystems, but also on human well-being and global economies, affecting wealthy nations as well. Furthermore, it disproportionately impacts rural communities in developing countries by threatening their access to vital food and water resources, while also increasing the risk of disease spread and the potential emergence of zoonotic outbreaks. To address this critical challenge, the Convention on Biological Diversity (CBD), in collaboration with the IUCN and leading experts in the field, has developed a practical Invasive alien species toolkit designed to help countries and communities take decisive action against the threat of biological invasions. Rather than a rigid rulebook, this toolkit offers flexible, step-by-step guidance divided into three core areas of intervention:

• Managing pathways: it helps identify and block the routes and vectors through which non-native species arrive in new territories, strengthening border controls and prevention measures.
• Prevention and early detection: it provides strategies to intercept high-priority and dangerous species before they can establish and spread permanently in local environments.
• Control and eradication: it outlines methods to remove or manage established populations of invasive species, placing a strong emphasis on protecting vulnerable and sensitive ecosystems, such as islands.

Ultimately, this resource combines operational guidelines, monitoring frameworks, and collaborative strategies to safeguard natural habitats and mitigate the ecological and socio-economic impacts of biological invasions.

To effectively tackle this challenge and move from global frameworks to tangible local action, governments, organizations, and project managers need a comprehensive, cyclical portfolio of tools and initiatives. Drawing from extensive professional experience in biodiversity conservation and biosecurity management, addressing biological invasions successfully requires a structured approach, beginning with deep analysis and data collection, moving through targeted strategic and operational development, and securing robust funding mechanisms for long-term implementation and monitoring. Below is an overview of the key instruments, frameworks, and strategic initiatives categorized by their operational phase:

1. Tools to be developed

Operational guidelines, regulatory frameworks, and capacity-building instruments that must be created or tailored at the national and local levels to establish a solid foundation for governance, prevention, and response.

• Guidance documents for governments and authorities
• Training programs and capacity-building curricula
• National targets and strategic objectives
• Pathway action plans (PAP)
• Early detection and rapid response (EDRR) protocols
• Risk management frameworks
• Behavior change communication campaigns
• Biosecurity manuals and codes of practice, including voluntary and professional codes of conduct
• Interpretative guidelines and documents for understanding complex elements, such as pathway categories and vectors
• Detailed manuals and standard operating procedures for monitoring and surveillance
• Practical field and customs identification guides tailored for border control officers and field personnel
• Synergies with other regulations and directives (e.g., within the EU nature directives, Wildlife Trade Regulations, Water Framework Directive, Animal Health and Plant Health laws)
• Customised templates for policy evaluation, National reporting on implementation, and risk assessments

2. Tools to be analyzed, mapped and populated

Information systems, scientific metrics, and participatory networks required to collect baseline data, track ecological indicators, assess risks, and monitor biological invasions over time.

• Databases and information repositories (e.g., EASIN, GISD, CABI, GBIF, DAISIE)
• Citizen science platforms and early warning apps (e.g., iNaturalist, smartphone apps, e.g. EASIN)
• Performance and headline indicators
• Gap analysis
• Species risk assessment and impact scoring (e.g., EICAT, SEICAT)
• Stakeholder mapping and engagement matrices
• Information flow and early warning networks analysis
• Pathway analysis and GIS mapping

3. Tools to be identified

Financial instruments, grants, and funding streams that need to be researched, mapped, and secured to ensure economic sustainability and continuous support for conservation and management projects.

• EU LIFE programme
• Fast-track rapid response grants
• Horizon Europe / Research grants
• National and regional environmental funds
• COST actions for networking and scientific collaboration
• Biodiversa+ partnership projects
• GEF (Global Environment Facility) funded projects

Implementing these tools doesn't always require massive budgets. With a strategic approach, smart resource allocation, and a phased roadmap, significant results can be achieved even with limited resources. However, navigating these complexities successfully requires relying on sound expertise and proven methodologies. 

Need expert support or strategic guidance for your next project? Let’s connect!

Having hands-on, comprehensive experience across all these areas, I can help you develop all the tools listed above, guide you in mapping and analysing the data and systems outlined in phase two, and assist in drafting competitive funding proposals by leveraging my direct experience with these financial mechanisms. 

I welcome opportunities to provide expert consultancy and strategic advice to international bodies and national governments, as well as other authorities and pratictionnaires. For inquiries or further information, please feel free to reach out at  or via LinkedIn to discuss how we can turn strategies into impactful results together.

Blue threat, blue crisis: the unfolding Mediterranean invasion

Also this summer, the Mediterranean is welcoming a massive crowd of sun-seeking tourists. But alongside the usual vacationers, another and far more relentless marine invasion is quietly transforming the basin: the rapid spread of alien species. While past decades taught us to watch out for iconic invaders like the so-called killer alga, Caulerpa taxifolia, today the phenomenon has scaled up dramatically across the board. Among the new protagonists of this ecological upheaval, the Atlantic blue crab Callinectes sapidus has swiftly colonized virtually every corner of the Mediterranean sea. In a remarkably pristine corner of Corsica, while monitoring a relic population of the Mediterranean’s largest native limpet - known to scientists as Patella ferruginea, a critically endangered mollusk heavily impacted by past human consumption - I stumbled upon an alarming discovery: the presence of this very blue crab in one of the few corners of our sea where the species was not yet recorded at that time. Finding it there brought an immediate realization of its potential threat to this fragile native icon. This observation was promptly reported to local authorities, emphasizing that every single record is vital for an early warning system to be effective and for adequate conservation actions to be undertaken in due time. 

Patella ferruginea © Photo: Riccardo Scalera 

This specific Corsican spot harbors one of the rarest, highly localized populations of the ferruginous limpet, fighting a desperate battle for survival. Conservation efforts like the EU-funded Re-Life Project, aimed at protecting and reintroducing limpets within target Marine Protected Areas in Liguria, in Northern Italy, highlight how delicate these recovery frameworks truly are. A voracious, opportunistic predator like the blue crab could easily breach these habitats, potentially pushing these iconic mollusks to the brink of extinction. The crisis, however, extends far beyond marine rocky shores. Astonishingly, this invasion does not stop at the coastline. Inland waters are increasingly under siege. The blue crab has managed to push deep into freshwater ecosystems, traveling up rivers and estuaries, such as the Po Delta in Northern Italy, where specimens have been documented pushing up to 100 kilometers inland into the heart of the Po Valley basin! 

Callinectes sapidus © Video: Riccardo Scalera 

For this reason, in Italy, public interventions, including millions of euros in extraordinary state resources, are attempting to support the mussel-farming and fishing sectors. These funds help offset severe gear damage, stock losses, and disposal costs, while also supporting specific initiatives, such as deploying protective underwater structures or barriers where fish and aquaculture stocks can find shelter from the relentless crustacean. Yet, despite growing alarm and a dedicated risk assessment conducted by the EU as early as 2020, the blue crab has been omitted from the latest updates of the EU list of invasive alien species of Union concern, following decisions made by Member States. Because it is already too widely established and abundant across the basin for eradication, official strategies are largely shifting toward commercial exploitation and intensive fishing to manage the biomass.

Distribution map of new records in the 
Mediterranean basin (from Pistevos et al. 2026)

By the way, the blue crab is merely the tip of the iceberg. It is definitely one of the most frequently recorded species, yet it represents just one of the nearly a thousand non-indigenous marine species that have successfully entered and reshaped the Mediterranean basin as a consequence of human activities.
But tracking an invasion of this magnitude requires a collective lens. Every single sighting, from a localized field survey on a protected limpet population to a network of researchers mapping new arrivals, matters. This philosophy of shared vigilance forms the backbone of our latest collaborative effort. In our newly published paper Unpublished Mediterranean and Black Sea records of marine alien, cryptogenic, and neonative species (III), part of a collective endeavor involving over 200 experts to document new alien species records across the Mediterranean, we highlighted how the influx of alien organisms is accelerating at an unprecedented pace, turning our familiar blue sea into an unpredictable, high-stakes ecological frontier. Because while a single blue crab in a pristine Corsican cove might feel like just another isolated data point, it is actually an early warning siren, and documenting them together is our best chance to defend what remains of our sea's fragile heritage.  

A global first: inside Europe’s groundbreaking funds against biological invasions

Those who deal with biological invasions are not alone, and they are certainly not left without resources in Europe. The iconic LIFE programme has been historically the primary instrument and main financial pillar for tackling invasive alien species across Europe for decades, even before the relevant Regulation (EU) No 1143/2014 came into force. Its tangible impact is demonstrated by extensive historical documentation, such as the landmark Alien species and nature conservation LIFE report and the 2015 compilation A catalogue of LIFE projects contributing to the management of alien species in the European Union, as well as milestone achievements like the international LIFE Ruddy Duck project, which successfully reduced the invasive ruddy duck population by over 95% to prevent the genetic extinction of the native white-headed duck, the LIFE Montecristo project in Italy, which successfully eradicated black rats in the 10.4 km² Montecristo island via aerial techniques, raising the breeding success of the endemic Yelkouan shearwater from 0% to over 90%, and very recent conservation triumphs like the LIFE RAFT project across Rathlin Island’s 14 km², which successfully achieved the world's first complete eradication of invasive ferrets from an island to safeguard over 250,000 breeding seabirds. 

Video animation © Riccardo Scalera

However, the operational landscape is shifting rapidly. As the deadline for submitting LIFE project proposals approaches, a wave of uncertainty surrounds its future. The European Commission’s proposals for the 2028–2034 financial cycle envision absorbing this programme into a broader European Competitiveness Fund. While interinstitutional negotiations remain wide open and nothing is yet definitive, this ongoing debate over whether these could be the final calls for traditional LIFE grants has pushed another vital financial instrument into the spotlight, drawing intense interest from the conservation world. 

A financial tool expressly dedicated to rapid response to biological invasions has been launched by the European Commission. This extraordinary initiative, implemented through the IUCN Save Our Species program, represents a fast-track mechanism that is potentially one-of-a-kind globally, specifically designed to intercept biological invasions before they spiral out of control. In the conservation world, waiting for absolute scientific certainty is a luxury we simply cannot afford; by the time years of data are gathered, an invasive population has often grown exponentially, rendering eradication impossible and long-term control astronomically expensive. Operating under the philosophy of acting early and fast, this fund injects quick capital into localized, early-stage incursions, offering an environmental and financial return up to twenty-five times higher than long-term management. More than just a grant, it aims to foster a true rapid-response mentality across boundaries. The fund is already powering key projects underway, from combining eDNA with targeted netting to combat American bullfrogs in Belgium and licensing divers to cull venomous lionfish in Croatia, to tackling alien lizard introductions in Crete. 

American bullfrog © Photo: Riccardo Scalera 

In a complex landscape dominated by economic uncertainty and shifting political priorities, this fund stands out as a concrete, accessible lifeline for nature conservation. An opportunity that no practitioner on the frontline of biodiversity protection can afford to miss. Ultimately, this pioneering European experience serves as a powerful, scalable blueprint that can hopefully be exported to other regions worldwide, proving that with coordinated political will and flexible funding, global biodiversity can be defended effectively against the rising threat of biological invasions. To gain a deeper perspective on how these fast-track conservation mechanisms operate in practice, you can view the complete panel discussion on the IUCN SOS Rapid Response webinar. This video features the project managers from the featured case studies discussing the real-world execution, data collection, and community engagement strategies supported by this initiative of the European Commission.

The biological invasions chronicles (from the archives of the 'Aliens' bulletin 2009–2013)

There was a time when the pulse of international conservation and the battle against invasive alien species resonated deeply through the pages of a very special newsletter. As a former co-editor of six historic issues of Aliens, the Invasive Species Bulletin, the publication of the IUCN Invasive Species Specialist Group, I often look back at that era with great fondness and satisfaction. Although the newsletter has recently undergone a complete transformation under a new editorial team, and the group's central website is undergoing a major restructuring, the legacy of those specific six issues - published from 2009 to 2013 - remains very much alive, as demonstrated by the citations they continue to receive to this day across numerous scientific articles.

Aliens: The Invasive Species Bulletin (2009-2013)

What truly defined the bulletin during our tenure was an uncompromised commitment to quality, driven nearly entirely by the authority of its contributors. It was never a peer-reviewed academic journal in the traditional sense, yet its reliability was absolute because it was penned by the world's leading experts who brought their firsthand field experience directly to our pages. It was an organic, almost artisanal endeavor, realized with the support of the Italian Institute for Environmental Protection and Research (ISPRA), which helped co-produce, print, and visually shape those issues before distributing them worldwide. In those days, the publication maintained a strong physical presence, with printed copies meticulously shipped to countless institutions and international libraries, where they survive today as tangible pieces of conservation history.

Looking back at the specific content of those six issues, it is impossible not to marvel at the groundbreaking and varied ecological challenges we had the privilege to cover. We brought our readers frontline accounts of remarkable management efforts, such as the eradication campaigns against the California kingsnake in the Canary Islands, the early-stage invasion responses to the yellow-legged hornet in France, and the innovative deployment of trained sniffer dogs in Australia to track down the hidden nests of invasive red-eared slider turtles. We documented continent-wide control strategies, from the cross-border management of the raccoon dog in Scandinavia and the complex strategies for managing the impacts of feral camels in Australia, to the delicate control efforts targeting the invasive American ruddy duck to protect native European waterfowl. Our pages also explored large-scale ecological disruptions, including the massive impact of introduced North American beavers in South America's Tierra del Fuego, alongside curious anomalies like the escape of African hippos into the rivers of Colombia.

These stories were not just news, but early warnings and invaluable case studies that anticipated many of the global biosecurity debates we face today. For anyone who remembers that vibrant era of conservation, or for those simply curious to explore the roots of modern invasion biology through these historic, home-grown pages, I warmly invite you to revisit these six issues through the links provided below:

• Issue 28/2009

• Issue 29/2010

• Issue 30/2010

• Issue 31/2011

• Issue 32/2012

• Issue 33/2013

And to the rare few who might still hold one of those original physical copies sent to libraries years ago, know that you possess a true relic of a time when passion, world-class expertise, and domestic ingenuity came together to protect the world's biodiversity!

The hidden invasion: how Japan’s "living fossil" 日本オオサンショウウオ is being erased from within

While biological invaders often cause obvious damage through predation or competition, hybridization is far more insidious. It is a silent invasion where a native species is not driven out, but simply fades away through "genetic swamping"...hidden in plain sight. This genetic erasure is well-documented, from introduced ruddy ducks (Oxyura jamaicensis) diluting Europe's native white-headed ducks, to sika deer (Cervus nippon) threatening European red deer, and non-native trout quietly erasing Italy's endemic freshwater lineages. Yet, nowhere is this invisible, total erasure more shocking than in the cold, rushing mountain streams of Japan.

The Japanese giant salamander (Andrias japonicus) - known locally as 日本オオサンショウウオ or in ancient Kanji as 大山椒魚 ("giant Sichuan-pepper fish," for the distinct peppery aroma it emits when threatened) - is a biological marvel! Growing up to five feet long and living for over a century, this fully aquatic amphibian has remained largely unchanged for 23 million years, earning it the nickname "living fossil." In the mid-20th century, however, humans introduced a catastrophic variable into this fragile ecosystem. In the 1970s, roughly 800 giant salamanders were imported from China to supply luxury restaurants, triggering the crisis. Because these animals were not native to Japan, they lacked any legal protection. When the government eventually shut the operation down, many of these imported Chinese giant salamanders (Andrias davidianus) escaped or were deliberately released into local river systems. Because the two species are closely related, they began to interbreed. The resulting hybrids are not only fully fertile but display "hybrid vigor" ...they are larger, highly aggressive, grow much faster, and are far more active than either parent species. During the breeding season, male salamanders must fight violently to control nesting burrows. The aggressive hybrids easily dominate these battles, systematically displacing native males, monopolizing the breeding sites, and rewriting the genetic code of the rivers through continuous backcrossing. As a result, the Japanese giant salamander in Kyoto’s Kamo River has officially become a "genetic ghost." 

The Japanese giant salamander (Andrias japonicus)
© Photo: Riccardo Scalera 

A 16-year population study spanning 134 surveys from 2005 to 2021 reveals that while these giant amphibians are still visually present, the pure native species is now virtually extinct in this habitat, its genome completely diluted by generations of hybrids. The few remaining pure individuals are aging rapidly without reproducing, leading to an irreversible demographic collapse. Traditional visual monitoring has proven entirely ineffective, with an individual detection rate of less than 0.1% per survey, allowing this introgressive hybridization to happen almost invisibly. To a casual observer, a hybrid looks identical to a native specimen: a magnificent, wrinkled, mottled-brown river creature. But on a genetic level, the pure Japanese species has been systematically erased.

Hybrid individuals between the Japanese giant salamander
and the Chinese giant salamander
© Photo: Mitsuhiko Toda, Japan Wildlife Research Center

To address this crisis, Japan recently updated its Invasive Alien Species Act, officially classifying these hybrids as invasive alien species. This crucial legislative shift removes past bureaucratic protections (which previously shielded hybrids due to their visual similarity to the protected native species) paving the way for aggressive, targeted eradication programs to prevent this silent genetic extinction from spreading to other river systems. Beyond genetics, Japan's heavily dammed rivers act as physical traps. Heavy rains wash salamanders downstream where vertical concrete walls block their return, causing severe injuries or forcing them into fatal, salty coastal waters. Trapped below these barriers, they are unable to reach safe nesting grounds, forcing females to spawn in unsuitable areas where their eggs are quickly lost. The threat is compounded by global warming. Rising summer temperatures are already delaying the salamanders' spawning season, raising fears that if Japanese summers continue to grow hotter, the species may soon be unable to breed at all. This double threat of genetic dilution and physical fragmentation means that these ancient creatures, which survived millions of years of evolutionary history, could completely disappear from rivers like the Kamo within the next 20 years. 

The Kyoto Aquarium salamander tanks with hybrids.
© Photo: Riccardo Scalera 

Researchers in Japan are now racing against time. They bypass visual identification entirely, utilizing environmental DNA (eDNA) technology to analyze water samples, detect genetic traces, and map out the remaining pure zones. Concurrently, a network of zoos, research hubs, and mountain sanctuaries is rushing to pull the last genetically pure individuals out of compromised waters and transfer them to isolated, protected facilities. This crisis is a powerful reminder that some extinctions happen in absolute silence. Ultimately, the survival of these ancient 'river dragons' points to a universal solution: a global commitment to restoring both genetic integrity and free passage in our waterways. This dual approach is the only definitive way to ensure that such irreplaceable evolutionary lineages do not quietly vanish.

New surveillance manuals to support biosecurity in the EU and beyond

More than 300 rapid eradication actions and 4,200 management measures implemented across Europe show that the fight against biological invasions is gaining momentum. Yet, invasive alien species continue to spread, and new introductions remain a constant threat. This stark contrast, recently highlighted by the European Environment Agency (EEA) in its latest briefing on the 2019–2024 reporting period, titled "Recent progress in managing invasive alien species in the EU" underscores a critical truth: detecting alien species before they wreak havoc on native ecosystems is the ultimate game of ecological hide-and-seek. 

Today, winning this war requires a fascinating paradox. On one hand, we are decoding secrets from single drops of water using eDNA and scanning landscapes with sophisticated drones. On the other, we still depend on the sharp noses of professional sniffer dogs and the unblinking gaze of remote camera traps. Invasive alien species represent one of the most aggressive threats to global biodiversity and the vital ecosystem services that sustain our societies, with the continuous expansion of global trade, transport, and tourism constantly accelerating the risk of new introductions. In this challenging scenario, timing is everything. When it comes to biological invasions, by the time an alien species becomes visible to the naked eye, the window for cost-effective eradication has often already closed. Reacting only when an invasion becomes glaringly obvious is no longer an option. For biosecurity managers and policymakers, mastering a multi-layered surveillance toolkit is a first line of defense, and understanding this hybrid web of surveillance is key to turning the tide. To meet this critical need, a major scientific and coordination initiative led by IUCN on behalf of the European Commission has resulted in the creation of two strategic documents designed to directly support EU Member States in implementing Regulation (EU) No 1143/2014. I had the privilege of coordinating the editing of these comprehensive works alongside an outstanding team of co-authors, delivering manuals built to transform theoretical policy into practical, cost-effective, and highly dynamic action on the ground.

The first report, Guidance on establishing surveillance systems for invasive alien species of Union concern in terrestrial and freshwater environments, serves as a user-friendly manual specifically designed to help managers and authorities implement and maintain effective surveillance systems. It focuses heavily on the requirements of Article 14 of the EU IAS Regulation, which mandates that Member States establish dynamic monitoring networks capable of both spotting new introductions and mapping the spread of already established species. Beyond early detection, the manual explains how surveillance data must feed into rapid response protocols, evaluate the success of eradication programmes, and inform the strict permitting systems required for scientific research or ex-situ conservation. To make this complex task highly operational, the manual avoids treating species entirely in isolation. Instead, it organizes the target 86 terrestrial and freshwater species into six thematic groups based on their environment and functional traits, which are terrestrial plants, freshwater plants, terrestrial invertebrates, freshwater invertebrates, terrestrial vertebrates, and freshwater vertebrates (marine species are excluded from this report). For each group, the guide provides detailed establishment scenarios, notes on the suitability of specific methods, and applications for broader management. The final section contains detailed, single-species accounts for each organism of Union concern, highlighting optimal survey periods, frequencies, and high-risk habitats where field efforts should be focused. Methodologically, the text bridges traditional visual surveys with cutting-edge innovations like environmental DNA (eDNA) and citizen science, while ensuring full compatibility with existing European monitoring frameworks like the Habitats and Water Framework Directives to maximize cost-effectiveness.

While that framework establishes the methodological and theoretical foundation, the second report Case studies on surveillance methods used for species of Union concern,  delivers the real-world operational evidence needed by practitioners. This report compiles a comprehensive registry of practical case studies for all 88 invasive alien species included in the Union list up to November 2024. In contrast to the terrestrial and freshwater focus of the first manual, this report spans all environments, including marine ecosystems, ensuring a completely comprehensive European framework. The focus here is entirely on field experience, documenting what actually works, the limitations encountered, and the specific surveillance protocols applied to target species. To ensure no species was left without a practical reference, whenever a specific case study was unavailable for a listed organism, we captured high-quality surveillance data from similar proxy species, focusing primarily on European efforts but looking globally whenever relevant. This creates an invaluable repository of lessons learned that prevents managers from having to reinvent the wheel.

These two reports do not sit on a shelf in isolation. Together, they form a synchronized toolkit that connects rigorous scientific methodology with practical field experience. By promoting an integrated approach that utilizes diverse and complementary methods, these documents aim to help Member States build a seamless, transboundary picture of biological invasions. Anticipating the arrival of these species through proactive, smart surveillance is our best and most efficient strategy to safeguard Europe's unique natural heritage, while establishing robust biosecurity standards that resonate across interconnected global environments beyond.

The symbolic dualism of snakes: balancing social perception and ecological integrity

As the Chinese Year of the Snake recently slithered to a close, it left behind a powerful reminder of our oldest contradiction. No other animal on Earth has managed to simultaneously evoke such visceral terror and such deep, reverent veneration. It remains our ultimate paradox: throughout history, snakes have been perceived as both healers and destroyers, a contradiction that reflects directly on modern conservation biology. In our current ecological crisis, this duality manifests in how we categorize them: we see native snakes as "good," fundamental predators essential for the balance of nature, while the "bad" ones are those invasive alien species that have a catastrophic impact on biodiversity and ecosystems.

In art, the dualism of snakes is frozen in Bernini’s Bust of Medusa,
where they symbolize both monstrous terror and the tragic beauty of transformation. 
© Photo: Riccardo Scalera 

Alien snakes are animals that humans, whether intentionally or not, have moved from their natural range to new territories. Here, in the absence of natural predators and thanks to an extraordinary ability to adapt to almost any prey, they transform into a silent threat capable of unbalancing entire ecosystems. The impact of these invasions is often devastating, generating what scientists call a 'cascade effect. In the Canary Islands, for instance, the introduction of the California kingsnake is driving endemic giant lizards (Gallotia) toward extinction; likewise, in Ibiza (Balearic Islands, Spain), the horseshoe whip snake (Hemorrhois hippocrepis) is pushing the endemic wall lizard (Podarcis pityusensis) to the brink. On the oceanic island of Guam (USA), the disappearance of birds due to the brown tree snake (Boiga irregularis) has even halted forest regeneration, as there are no longer animals to disperse seeds. Beyond environmental damage, we must not underestimate health risks: these reptiles can carry parasites and pathogens, such as Salmonella or exotic viruses, which are dangerous to both local wildlife and humans.

But how do these animals reach such distant lands? The entry routes, or pathways, are manifold and often surprising. To understand these pathways, we must first dispel persistent urban legends. For example, in Italy, a popular belief suggests that vipers are reintroduced by being released from helicopters in small boxes. This is a complete myth; conservation is never conducted through such haphazard or clandestine means. The actual mechanisms of introduction are far more practical and directly linked to human activities and behaviours. The pet trade is a primary channel: animals often escape or are abandoned by owners when they become too large or demanding. It is a cruel paradox: this misguided sense of compassion leads owners to release pets into the wild, unaware that they are essentially sentencing the individual to perish in an alien habitat or, conversely, sentencing native species to extinction. In either case, the act disrupts the ecological integrity we aim to protect. There are also unintentional pathways, such as the transport of goods and waste, including military equipment in the case of the brown tree snake, or even horticulture, where eggs and small snakes travel hidden within the root balls of olive or ornamental trees, overcoming otherwise insurmountable geographical barriers. Even history teaches us how humans have reshuffled nature: from the ancient Romans or Hannibal, who launched snakes as psychological weapons, to the monks who, around the Middle Ages, introduced vipers (Vipera aspis) to Monte Cristo (Tuscan archipelago, Italy) for therapeutic purposes.

Managing this issue is one of the most complex challenges in conservation biology. The strategy must be based on three pillars: prevention, early detection and rapid eradication, and management (eradication, control, or containment). Prevention remains our most effective weapon. Through the tools of horizon scanning and risk assessment, scientists evaluate the danger of species not yet present to inform policymakers. This allows the most high-risk species to be flagged and potentially included in blacklists, which allow for action to be taken. The European Union's Regulation on invasive alien species, for example, is based on a list of "species of Union concern," which allows for the blocking of their keeping and trade before the damage is done. The kingsnake, Lampropeltis getula, is the first and only snake listed so far.

The identification cards of Lampropeltis getula
made by the European Commission for customs

To support these efforts, the scientific community is more active than ever. By working at the science-policy interface, experts are collaborating with the European Commission to produce tools not only to inform policymakers but also wildlife managers. For example, in 2020, an international workshop was organized, gathering the world's leading experts led by IUCN to share best practices. This collaboration resulted in a comprehensive report on the management of invasive alien snakes, now officially available online through the European Commission, which serves as a global roadmap for tackling these invasions. Other tools were also developed to increase awareness, such as guidance for surveillance and relevant case studies, identification guides, cards, and posters specifically for kingsnakes. These show similar species in trade for customs officers, along with similar species occurring in the field for wildlife managers. The listing of the kingsnake also allowed for action to be taken, resulting in several propagules being removed in countries like Germany, Denmark, and Ireland, as documented by the NOTSYS platform managed by the Joint Research Centre.

The report of the European Commission
on the management of invasive alien snakes

However, if prevention fails, eradication becomes a race against time that is almost impossible to win. Snakes are masters of elusion: they live underground, in trees, or move under the cover of night, and their young are virtually invisible. We must be honest: snakes are nearly impossible to manage once introduced, as current techniques are not sufficiently effective. Thus, when total removal is no longer feasible, the only options left are numerical control to reduce predatory pressure or the creation of "sanctuaries", fenced and protected areas where snakes are excluded to save species on the brink of extinction.

This presents us with a profound ethical dilemma: the removal of an alien individual is not an act of hate, but a necessary choice to protect the right to survival of an entire native species. Ultimately, the responsibility is ours. The primary challenge is not merely to remove and manage invasive alien snakes, but to change human behavior. We must ensure that the importance of keeping snakes in their own ecosystem and not moving them beyond their natural range is recognized as key to respecting the boundaries that evolution has drawn over millions of years.

The fine art of biological invasions foresight

Much like a crystal ball, horizon scanning allows us to catch a fleeting glimpse into the future. This is the magic of forward-looking studies, the same which allow businessmen to decide where to invest and meteorologists when to pack an umbrella. For ecologists, this same foresight reveals which biological storms are gathering at the border. In invasion biology, waiting for the rain to fall means you are already soaked. Invasive alien species, alongside climate change and habitat destruction, are primary drivers of global biodiversity loss. Beyond disrupting ecosystems, they impact human health, the economy, and act as subtle vectors for wildlife pathogens. Because managing an invasion after establishment is a massively expensive and often losing battle, science is striving to shift from reactive management to proactive planning. This is precisely where horizon scanning steps in as the answer.

This approach is already successfully applied in sectors like plant and animal health to intercept agricultural pests and livestock diseases before they trigger outbreaks. Notably, this cross-sectoral synergy was a central theme at the 3rd International Scientific Workshop on Horizon Scanning for Plant Health, organised by the European Food Safety Authority (EFSA), where an international panel of experts addressed these shared challenges. The workshop's official summary features a presentation of my own contribution to the field, which serves as the foundational basis for this article. In invasion ecology, this foresight specifically targets the human activities driving species movement. By analyzing trade routes and climate shifts, it flags "door-knocking" species: high-risk disruptors sitting just outside our borders, ready to invade.

In the European Union for example, to prioritize threats within Regulation (EU) No 1143/2014, the European Commission launched two major region-wide horizon-scanning exercises in 2015 and 2026. Both exercises utilized the Delphi method, a consensus framework where experts across five thematic groups (covering plants, vertebrates, terrestrial invertebrates, marine, and freshwater ecosystems) first drafted preliminary risk scores through literature reviews and then finalized them during a collaborative workshop. Throughout this process, species were systematically evaluated based on their likelihood of arrival, establishment, spread, and potential biodiversity impact.

The main hurdle in this predictive art is volume. The 2026 exercise faced an initial longlist of nearly 9,000 species, filtered down to some 4,000 by removing clear climate mismatches or species lacking an invasion history. Ultimately, 622 species were debated at the consensus workshop, classifying 57 as "very high risk" and 108 as "high risk." While automated tools like climate matching and occupancy analysis were implemented to streamline the screening, the results highlighted the strict limits of automation. Incomplete baseline data often led to unreliable outputs, and automated models frequently failed to capture complex ecological requirements. This proved a critical lesson: automated tools are useful for flagging risks, but they cannot replace the nuanced, qualitative judgment of expert networks. 

Crucially, horizon scanning is a prioritization filter, not a mitigation strategy, just the initial step before a full risk assessment and formal EU listing. The looming invasion of the red imported fire ant (Solenopsis invicta) in Europe exposes the challenge in this pipeline: flagged as a top priority "door-knocker" in 2015 and risk-assessed in 2017, it was officially listed only in 2022. But it was too late. The ant had already established itself in Sicily by 2019, remaining undetected until 2023. This case proves that even the most advanced foresight tools fail without rapid information flow and immediate policy enforcement.

Fire ant (Solenopsis invicta)
Drawing made by Massimiliano Lipperi © European Commission

The fire ant case demonstrates that without a seamless, rapid handoff from foresight to policy enforcement, the best-scanned horizon remains just a picture of an impending, unmitigated crisis. For a forward-looking study to truly protect biodiversity, the scientific alarm must be met with an immediate, synchronized, and aggressive legislative response. Eventually, the critical challenge is now to integrate, harmonize, and find deep synergies between the methods applied in the field of biological invasions with those utilized in animal and plant health. Alongside this cross-sectoral alignment, we must place a strong emphasis on increasing the efficiency of automated studies. By refining these digital frameworks to minimize baseline data gaps, we can optimize resources, reduce the reliance on purely manual filtering, and perform much quicker screenings. Ultimately, bridging the science-policy gap, embracing automation responsibly, and fostering cross-disciplinary collaboration remain the most critical steps in transforming these prioritized lists from mere warnings on a page into tangible, swift conservation outcomes.

Beyond decoration: restoring the role of plants in global health

Though plants are omnipresent in our daily lives, we frequently fail to perceive them as anything more than inert green scenery. We are accustomed to valuing them merely as decorative elements or as simple providers of food and oxygen, yet we often overlook the profound impact they have on ecosystem resilience and our overall well-being. We have become so used to treating the botanical world as a silent setting that we forget plants are actually lead actors in our health and survival; while experts remain preoccupied with animals and pathogens, they risk ignoring the very entities that possess the power to either ignite or prevent the next global health emergency.

The One Health approach is an integrated framework designed to recognize the fundamental interdependence of human, animal, and environmental health. Its primary objective is to move beyond siloed management toward a collaborative system that fosters long-term prevention and ecosystem resilience rather than just reactive crisis management. However, current implementations often suffer from "plant-blindness," where plants are treated as a passive backdrop rather than as dynamic and active determinants of health. As described in the policy brief published within the B-Cubed and OneSTOP projects, this gap creates a structural bias toward animal and pathogen focused policies, leading to suboptimal responses and missed ecological drivers. Within the One Health framework, this "plant-blindness" causes us to overlook organisms that serve both as the essential foundation of our well-being and as the hidden drivers of emerging health crises.

A significant part of this problem stems from a governance and implementation gap where practitioners frequently misuse the terms "environment" and "ecosystem" as synonyms. In practice, the "environment" is often reduced to abiotic factors like climate and pollution, which obscures the specific role of plants as health actors. By strictly defining the environment as the physical context and the ecosystem as an interactive biological network in which plants are central, we can better integrate plant health into the One Health framework.

Plants serve as the essential foundation of health, underpinning everything from global food security and primary healthcare to the stability of microbiomes that influence human and animal immune systems. A critical but frequently ignored aspect of this relationship is the role of invasive alien plants, which act as direct drivers of disease and systemic health stressors. Ecologically impoverished systems are not only less tolerant to climate change but are also more susceptible to biological invasions, as the lack of plant competition allows invasive alien species to dominate and further degrade valuable land and disrupt delicate ecosystems. While diversity provides resilience, the spread of invasive alien plants like Prosopis juliflora undermines food security and heightens human vulnerability to allergies and vector-borne diseases, including malaria transmission. Other species may trigger direct pathologies, such as ragweed-induced (Ambrosia artemisiifolia) allergies or skin damage from giant hogweed (Heracleum mantegazzianum), and facilitate the proliferation of disease vectors like the water hyacinth (Pontederia crassipes) does for mosquitoes.

Water hyacinth surrounded by mosquitoes
(AI-generated image)

To address these systemic gaps, it is essential to explicitly include alien plant-driven health risks within One Health monitoring and governance. Prioritizing native plant diversity and monitoring biological invasions is essential to building the "biotic resistance" required for systemic disease prevention. By investing in taxonomic expertise and integrating plant community data into vector monitoring, the One Health approach can become truly operational and capable of sustaining healthy environments for all. 

Of people and snakes: slithering between ancient myths and community science

There is a truly unique event that takes place every year in the heart of Italy, where the boundaries between the human and the wild simply dissolve. It is a story of snakes. Of people and snakes. The ancestral fascination - that unique mix of wonder and fear - finds a profound synthesis in Cocullo, a small village nestled in the heart of the Abruzzo Apennines. Here, the Feast of San Domenico Abate takes place. It is a unique sacred-profane ritual where the statue of the Saint is draped in live serpents and carried through the streets by serpari (snake-catchers). The rite symbolizes the reconciliation between man and nature, transforming ancestral fears into a powerful celebration of spiritual protection and environmental stewardship.

San Domenico draped in live four-lined snakes 
during the procession of the serpari 
© Photo: Riccardo Scalera 

This unique cultural landscape has evolved into a visionary, long-term "community science" event on snake protection, the greatest and genuine ever seen in Italy and beyond. In the weeks leading up to the May 1st celebration, the serpari traverse the surrounding territory to collect the snakes, providing a rare and precious opportunity to investigate the biology of these species in their natural habitat. By bridging the ancient skill of the search with the modern rigor of data collection, their precious knowledge and respect for nature and wildlife have developed into a fascinating crossroads where modern herpetological science meets tradition, effectively blending cultural heritage with the systematic gathering of biological data. In addition to that, the event also become a very popular tourist attraction for enthusiasts and curious people of all ages coming from all over the country and beyond.

This sacred-profane ritual hence allowed for the collection of a vast amount of data on snakes, effectively transforming the local serpari into true "custodians of biodiversity." Working under official permits, these practitioners treat the animals with immense care and respect, fostering a deep sense of environmental responsibility that permeates the entire community. This shared commitment is what has enabled over 15 years of rigorous scientific monitoring, ensuring that the ancient tradition serves a modern ecological purpose. Data are collected by renowned herpetologists with the vital contributions of leading veterinarians from the University of Bari and other experts who work in close step with the local serpari. A fundamental aspect of this work is that all captured specimens are marked with a PIT tag (microchip). This allows for individual identification and serves as a crucial measure to abide by the law. Since these species are protected under the EU Habitats Directive, the marking system ensures compliance with the specific legal derogation granted for this rite, providing a transparent and regulated framework for the study of the four-lined snake (Elaphe quatuorlineata), the Aesculapian snake (Zamenis longissimus), the barred grass snake (Natrix helvetica), the smooth snake (Coronella austriaca), the southern smooth snake (Coronella girondica), and the green whip snake (Hierophis viridiflavus).

A rare smooth snakes captured by the serpari
© Photo: Riccardo Scalera 

Data collected across the years confirms the sustainability of this practice. Many individuals are recaptured time and again, showing regular growth and no evidence of harm from the ritual, proving that these reptiles are thriving within their ecosystem despite their annual role in the procession. Crucially, the project integrates a One Health perspective through in-depth veterinary investigations that monitor the reptiles' health as a vital bio-indicator of the broader environment. By recognizing that the well-being of the community, the wildlife, and the local habitat are inextricably linked, the event has become a fundamental platform for ecological research and public health awareness.

A green whip snake being examined for mites
© Photo: Riccardo Scalera 

This evocative atmosphere and the delicate balance between science and society is masterfully captured in the book Slither by Stephen Hall, where the story of this celebration is described with rare sensitivity and depth. Having had the privilege of meeting the author and sharing the experience of the festival with him, I was impressed by his extraordinary personality and his rich background as a journalist specifically focusing on science and society - and his long-time tenure as a correspondent in Italy. For those interested in the many unknown facts and stories of snakes and humans, this book is an essential guide. Stephen Hall explores a wide array of compelling themes, ranging from the surprising parental care found in rattlesnakes to the biological marvels of pythons that physically remodel their internal organs to digest each meal. He further delves into the rapid evolution of venom as an environmental adaptation and even traces the roots of holistic medicine back to the proto-hospitals of Pindar’s Greece.

These stories serve to reconcile myth with biology, much like the rite of Cocullo itself. Ultimately, the annual Feast of San Domenico Abate stands as a powerful symbol of community resilience, successfully bridging ancient faith with modern ecological stewardship while solidifying its status as a vital piece of Italian cultural heritage.

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.