invasive alien species

Pensoft at NeoBiota 2026: Talking about Europe’s Invasive Species Response

Pensoft Publishers took part in the 14th International Conference on Biological Invasions (NeoBiota 2026) in Brussels, Belgium, between 7-11 September 2026.

Pensoft Publishers took part in the 14th International Conference on Biological Invasions (NeoBiota 2026) in Brussels, Belgium, between 7-11 September 2026. The well-established biennial series brought together researchers, practitioners, policymakers and stakeholders from around the world to share cutting-edge scientific research on biological invasions.

Over five days, the conference covered the full arc of the field, from how alien species arrive and spread to what they do to ecosystems and to people. The conference sessions also tackled how risks are assessed and prioritised, and what management, policy and public engagement can realistically achieve.

Pensoft’s Presence

During the days of the conference, we showcased our journals’ portfolio and project materials from OneSTOP and other projects, which were of interest to the participants.

Pensoft’s stand at the 14th International Conference on Biological Invasions.

More specifically, Pensoft was represented with a booth showcasing the relevant journals such as:

NeoBiota – publishes all disciplines interested in biological invasions, specifically on the ecology, evolution and biogeography of non-indigenous aquatic and terrestrial animals, plants, fungi and micro-organisms
Nature Conservation – publishes all disciplines interested in basic and applied conservation ecology and nature conservation in general at various spatial, temporal and evolutionary scales
Biodiversity Data Journal – publishes biodiversity science containing taxonomic, floristic/faunistic, morphological, genomic, phylogenetic, ecological or environmental data on any taxon of any geological age from any part of the world
Metabarcoding and Metagenomics – publishes on metabarcoding and metagenomics from both basic and applied aspects
One Ecosystem – provides a forum for studies in the field of ecology and sustainability
PhytoKeys – publishes in systematic Botany containing taxonomic/floristic data on any taxon of any geological age from any part of the world
MycoKeys – publishes on the monophyletic kingdom Fungi containing taxonomic or ecological data on any taxon of any geological age from any part of the world
ZooKeys – launched to support free exchange of ideas, data and information in all branches of Zoology
Research Ideas and Outcomes – publishes all outputs of the research cycle, including: project proposals, data, methods, workflows, software, project reports and research articles

Pensoft at the 14th International Conference on Biological Invasions.

During the days of the conference, we met many project partners and journal editors. Indeed, Pensoft’s presence at the conference was significant, with a Pensoft NeoBiota editorial meeting held and the Pensoft Award for the Best Talk given by Ana Novoa to Rajat Rastagi at the closing ceremony of the conference.

The Highlights

Pensoft Editorial Meeting

On Tuesday evening, NeoBiota convened its editorial board to review the journal’s progress. The meeting highlighted significant developments, including increases in article submissions and continued improvement in the journal’s impact and reputation within the field.

NeoBiota Editorial Meeting, 2026.

Visiting Meise Botanic Garden

On Wednesday, meanwhile, we visited Meise Botanic Garden, the home of OneSTOP’s coordinators and the Plant Ecology and Evolution journal. The trip allowed us to meet some editors from the journal and talk to them about their plans and publications. In addition, the project OneSTOP was showcased, and the walk in the garden allowed participants to test OneSTOP’s web app for the identification of invasive species.

Meise Botanic Garden, 2026.

Notable Presentations

While the conference included numerous notable presentations, Joana Vicente’s keynote Prioritisation in the Age of Invasion Science: From Risk Ranking to Adaptive Governance, is especially worth mentioning. Joana represented BIOPOLIS-CIBIO, one of OneSTOP’s partners, and showcased OneSTOP’s work in prioritisation. The key takeaway was as follows:

“Prioritisation should not be a one-off ranking of species but an ongoing, adaptive process built into how invasions are governed”.

Joana Vicente presenting at NeoBiota 2026.

Another important session was one on Friday morning, where Quentin Groom (coordinator of OneSTOP and author, reviewer and subject Editor in Biodiversity Data Journal, NeoBiota, One Ecosystem) presented the importance of developing an early-alert system for invasive alien species in the session – From prototype to infrastructure: building a cross-realm European alert system for invasive alien species.

Quentin Groom presenting at NeoBiota 2026.

During the session, he showcased how such a system would help the management of IAS and highlighted the work that has already been done for its development by OneSTOP and its sister project GuardIAS.

The Takeaway

NeoBiota 2026 has closed, but the work of limiting the spread and impact of invasive alien species does not pause between conferences. We met many project partners and editors from journals, and talked about the next steps in the science of biological invasions.

Follow us on Bluesky, Facebook, X, and LinkedIn for future conference updates.

A new crab is settling in the Mediterranean: early evidence of establishment of a Lessepsian species in the Ionian Sea

New research reveals the rapid expansion of the portunid crab, Gonioinfradens giardi, highlighting ongoing biological changes in the Mediterranean Sea.

Guest blog post by Francesco Tiralongo

The Mediterranean Sea is undergoing rapid ecological transformations driven by climate change and human-mediated species introductions. Among the most striking processes is the increasing arrival and establishment of non-indigenous species entering through the Suez Canal, a phenomenon known as Lessepsian migration.

A new study published in Acta Ichthyologica et Piscatoria documents the rapid expansion of the Indo-Pacific swimming crab Gonioinfradens giardi in the Ionian Sea, off the coast of Italy. Following the first confirmed Italian record – a single specimen collected at Portopalo di Capo Passero in November 2025 – researchers documented 11 additional individuals between November 2025 and January 2026, providing early evidence that the species has moved beyond sporadic occurrence and may already be establishing stable populations in the region.

@pensoft.publishers
🦀A new study highlights the rapid expansion and early establishment of the non-indigenous Indo-Pacific swimming crab, Gonioinfradens giardi, along the Ionian coast of Sicily in the Mediterranean Sea The research was published in the open-access journal Acta Ichthyologica et Piscatoria. 👉Full article here: Tiralongo F, Leotta P, Accolla H, Tibullo D, Felici A (2026) Rapid expansion of a Lessepsian migrant crab, Gonioinfradens giardi (Crustacea, Brachyura, Portunidae), in the Ionian Sea: New records and early evidence of establishment. Acta Ichthyologica et Piscatoria 56: 145-149. https://doi.org/10.3897/aiep.56.185183 #invasivespecies #conservation #italy
♬ Aesthetic – BoominBeats

Our findings suggest that Gonioinfradens giardi is transitioning from occasional records to a more consistent presence in the central Mediterranean. This raises important questions about its potential ecological role and interactions with native species.
explains Francesco Tiralongo, lead author of the study

To reconstruct the current distribution of the species, the newly collected data integrates recent records with field observations obtained through a collaboration with local fishers utilizing standard artisanal fishing gears.

The haul of a dozen individuals within a two-month period indicates that environmental conditions are becoming more favorable for its persistence. Furthermore, these captures mark the westernmost presence of the species in the Mediterranean Sea to date.

Distribution map of *Gonioinfradens* *giardi*; new records along the Ionian coast of Sicily are shown in yellow (circles), while the red circle indicates the first published record. Credit to Tiralongo et al., 2026

The rapid emergence of this species highlights how dynamic and responsive Mediterranean ecosystems are to ongoing environmental changes. Documenting these early phases of establishment is crucial for understanding future ecological scenarios and supporting informed management decisions.
adds Alberto Felici, co-author of the study

The establishment of non-indigenous crustaceans may have cascading effects on local ecosystems, including competition with native species and potential implications for fisheries. While the long-term impacts of G. giardi remain uncertain, its rapid spread reflects broader changes already underway in Mediterranean marine biodiversity.

*Gonioinfradens giardi*, credit to Francesco Tiralongo.

This case adds to a growing list of species reshaping Mediterranean ecosystems. Continuous monitoring, including contributions from fishers and citizen scientists, will be essential to track these dynamics and support adaptive management strategies.
Tiralongo adds

A YouTube video by the study’s lead author, Francesco Tiralongo, in which he introduces Gonioinfradens giardi – a species relatively unknown in the Mediterranean – explains its origin, describes how it entered the ecosystem, and outlines its current distribution in Italian waters as well as its potential impacts on ecosystems and fisheries.

The study contributes to the expanding body of evidence that the Mediterranean Sea is becoming a hotspot for biological invasions, emphasizing the need for coordinated research and monitoring efforts at regional and basin-wide scales.

Original source:

Tiralongo F, Leotta P, Accolla H, Tibullo D, Felici A (2026) Rapid expansion of a Lessepsian migrant crab, Gonioinfradens giardi (Crustacea, Brachyura, Portunidae), in the Ionian Sea: New records and early evidence of establishment. Acta Ichthyologica et Piscatoria 56: 145-149. https://doi.org/10.3897/aiep.56.185183

Call Me Invasive: New Evidence Confirms the Status of the Giant Asian Mantis in Europe

These mantises are increasingly threatening local biodiversity through aggressive predation and reproductive competition.

In the realm of entomology, few creatures command as much fascination as the mantis. Throughout history, these striking insects have been deeply woven into local myths and legends, sometimes respected as mystical soothsayers that can guide lost travelers home, and other times feared as little devils.

Today they remain captivating animals, serving as excellent bioindicators of biodiversity, and helping us identify rich and diverse ecosystems when present as native species.

However, a new study published in the open-access Journal of Orthoptera Research reports that two mantis species identified in Europe – Hierodula tenuidentata and Hierodula patellifera – have been formally recognised as Invasive Alien Species (IAS). This shift in status highlights a growing threat to the biodiversity that native mantises typically help us protect. Led by Roberto Battiston of the Museum of Archaeology and Natural Sciences “G. Zannato”, a team of researchers investigated the impacts of these native to Asia species on European ecosystems which, until now, were largely unknown.

According to Battiston, these mantises have been present in Europe for about a decade, but their numbers have recently exploded in the Mediterranean and continental regions.

“They are pushing increasingly further north, thanks to climate change,” Battiston explains, noting that viable populations are now frequently spotted by the public in local parks and gardens. Because they are large and fascinating, they often inspire more curiosity than concern, with members of the public frequently wondering if these striking insects are a positive sign for their local environment.

“This study was born to give people those answers and to develop strategies to contain them.”

Hierodula patellifera eating a wasp and honeybee. (Photo credit: Roberto Battiston).
Hierodula eating Mantis religiosa. (Photo credit: Massimiliano Bonatti).

Hierodula tenuidentata and Hierodula patellifera are large and adaptable tree-dwelling predators, characterised by their high reproductive potential. They are capable of hatching an average of around 200 nymphs per egg case, which is almost double that of the native European mantis (Mantis religiosa). Coupled with their low rate of cannibalism among young nymphs, they are able to grow very rapidly.

Size comparison of patellifera (on the left) and tenuidentata (on the right). (Photo credit: Roberto Battiston).
Roberto Battiston (left) and William Di Pietro (right) conducting field research. (Photo Credit: Roberto Battiston).

These species are considered particularly dangerous to local biodiversity because they fatally lure native males into mating attempts that end in the males being eaten, potentially depressing native populations. They additionally consume a wide range of other native species, including essential pollinators like honeybees, and small protected vertebrates such as lizards and tree frogs. These negative interactions demonstrate the need for urgent assessments, particularly in Mediterranean islands with endemic species of invertebrates and vertebrates.

Negative interactions of Hierodula preying on vertebrates – Wall lizard. (Photo credit: Flavio Basilico).
Negative interactions of Hierodula preying on vertebrates – Wall lizard. (Photo credit: Primo Chittaro and Caterina Biscaro).
Negative interactions of Hierodula preying on invertebrates. (Photo credit: Antonella Bianchi, Sebastiano Mattia Silenzi, Davide Maistrello, Simona Tenani and Matteo Algeri Bricoli).

Interestingly, domestic cats have emerged as the primary vertebrate predator of the invasive Asian mantises, accounting for 45% of recorded positive predation events. Battiston notes that while cats serve as an effective means of containment for these invaders, they are unable to distinguish between alien and native species. Consequently, roaming cats also prey on native species like the European mantis, which already suffer competition from their exotic cousins in peri-urban environments and are in decline.

Positive interactions of vertebrates preying on Hierodula – Domestic cat. (Photo credit: Patrizia Ruggeri).
Athene noctua – The Little Owl. (Photo credit: Marina Zambelli).
Cyanistes caeruleus – Eurasian blue tit. (Photo credit: Alessandra Previtali).
Dendrocopos major – Great Spotted Woodpecker. (Photo credit: Alessandra Previtali).

Human-modified environments, particularly in urban and suburban areas, significantly facilitate the expansion of Hierodula mantises. These insects utilise artificial structures, such as insect hotels, as concentrated hunting grounds, and leverage urban heat islands to survive longer into colder months. Thus, by exploiting human infrastructure and localised warming, these mantises are successfully extending their range and survival beyond natural limits.

To mitigate the spread of Hierodula, Battiston mentions the following initiative:

“My colleagues William di Pietro and Antonio Fasano (GRIO) have managed to set up a huge citizen science project and collect over 2,300 reports from enthusiasts and citizens. Citizen science is a fundamental tool not only for monitoring but also for raising awareness and informing people in an active and participatory way about these issues.”

Hierodula patellifera. (Video credit: Roberto Battiston).

Beyond reporting sightings, the public can also take direct action by intervening during the winter months when trees and shrubs are leafless. During this time, the oothecae – brownish, spongy egg cases about 2-3 cm in size – are well-exposed and easily recognisable on branches. While these cases are easy to remove and their destruction is painless, Battiston cautions that the public should always consult a specialist before removal to ensure that they are not accidentally targeting native mantises.

Hierodula patellifera eating a wasp and a bee at the same time. (Video credit: Roberto Battiston).

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The expansion of the Asian mantis is a powerful reminder of how human activity shifts natural boundaries and makes active community-led conservation more important than ever. As these adaptable invaders continue to reshape European ecosystems, our collective vigilance and participation in citizen science are effective tools for protecting Europe’s native biodiversity.

Original source:

Battiston R, Di Pietro W, Boscato F, Fasano A (2026) Call me invasive: Testing the first impacts of the alien mantises Hierodula patellifera and Hierodula tenuidentata on European biodiversity. Journal of Orthoptera Research 35(1): 179-190. https://doi.org/10.3897/jor.35.165233

For more interesting articles on orthoptera, visit the Journal of Orthoptera Research website and follow us on Bluesky and Facebook.

Hornet invaders: British public urged to report yellow-legged bee killers

Originating from Asia, invasive yellow-legged hornets have spread across western Europe, threatening bee populations.

Researchers have emphasised the vital role of public reporting in controlling the invasive yellow-legged hornet (also known as the Asian hornet) in Great Britain.

Indigenous to Southeast Asia, the hornet (scientific name: Vespa velutina nigrithorax) was first detected in France in 2004 and has since rapidly spread across western Europe, including Great Britain.

Tracking an invasion – a single Asian hornet sparked the ongoing spread across Europe

This species poses a serious danger to native pollinators, especially honeybees (Apis mellifera), which lack natural defenses against the hornet’s predation. The hornet’s arrival threatens both biodiversity and the beekeeping industry, with intense predation leading to depleted colony reserves and deaths.

A new research paper published in the open-access journal NeoBiota presents a simulation model that predicts the hornet’s dispersal and gauges how long official nest-detection efforts could remain effective before being overwhelmed. The model considers natural dispersal, genetic factors such as the production of diploid (and therefore infertile) males and the realistic distribution of public observers in the landscape.

Without public reporting, the study found that hornet populations in Britain could become unmanageable within 3–7 years of undetected spread, overwhelming resources for nest detection and destruction. However, when public and beekeeper reports are incorporated, control efforts can remain effective for at least 10 years, with this window extending based on reporting rates and observer density.

Three maps of Great Britain showing a decreasing density of hornet sightings correlating with increasing public reports. — Mean density of undetected nests (per km²), estimated at year six for scenarios involving two incursions per year. A) Average density in scenarios where control is absent B) Under the lowest national reporting probability C) Under the highest national reporting probability. Each scenario was estimated across all 100 simulations.

Proximity to populated areas greatly increases the likelihood of successful nest discovery and destruction as they are much better protected due to frequent sightings and reports. Conversely, nests in remote or sparsely populated zones pose a greater risk of escaping detection and fueling further invasion.

Public awareness campaigns, online reporting tools, and targeted outreach to beekeepers have proved highly effective. For instance, in 2023, nearly 21,000 public reports led to 72 nests being destroyed. Now researchers call for continued improvement of such engagement strategies, especially in vulnerable low-density regions.

Do think you’ve seen a yellow-legged hornet in Great Britain? Report it here.

Original source

Warren DA, Budgey R, Semmence N, Jones EP, Jones B (2025) Public reporting is essential for controlling the invasive yellow-legged hornet: a novel model simulating the spread of Vespa velutina nigrithorax and timescales for control in Great Britain. NeoBiota 101: 25-44. https://doi.org/10.3897/neobiota.101.148570

A toxic pufferfish (that could bite off your fingers) has been found in Croatian waters

The silver-cheeked toadfish has spread aggressively in the Mediterranean since entering through the Suez Canal.

On May 13, 2024 researchers discovered a highly invasive silver-cheeked toadfish (Lagocephalus sceleratus) in the Bay of Medulin, just off the coast of Croatia. The 52 cm, 1.3 kg male represents the northernmost record of the species in the Mediterranean, raising serious concerns about potential impacts on marine biodiversity, fisheries, and coastal tourism.

Pufferfish specimen on a metal plate. — Specimen of *Lagocephalus* *sceleratus* (♂) from Medulin Bay, Croatia.

Originating from the Indo-Pacific, Lagocephalus sceleratus is a ‘Lessepsian migrant’ (meaning it migrated through the artificially created Suez Canal) and has spread aggressively through the Mediterranean since its first sighting in 2003. This latest discovery is the fourth confirmed record of the species in the Adriatic and the first from its northernmost waters.

Map of Medulin Bay, Croatia. — The area in the northern Adriatic Sea where *Lagocephalus* *sceleratus* was caught, Medulin Bay, southern Istria, Croatia.

Recent evidence from the southern and eastern Mediterranean shows that bites from the powerful beak-like jaws of the species can result in severe injuries such as partial amputations of fingers. Its flesh and organs also contain a potent neurotoxin, tetrodotoxin, which can be lethal if consumed.

In Mediterranean coastal regions, Lagocephalus sceleratus has become an increasingly significant portion of small-scale fishing catches, often causing damage to fishing gear with its bite. Stomach analysis of the captured individual revealed a diet consisting of bivalves, gastropods, and sea urchins, suggesting potential disruptions to the Adriatic’s ecological balance.

Map showing the Adriatic Sea with five circles marking sightings of the species since 2012. — Adriatic records of *Lagocephalus* *sceleratus*.

“The presence of Lagocephalus sceleratus in the northern Adriatic is a clear warning sign of the species’ expanding range and potential ecological and economic consequences. Proactive monitoring and management strategies are important to mitigating its impact on local marine biodiversity, fisheries, and public safety.”
Dr Neven Iveša, co-author of the study.

Experts recommend increased monitoring, regulatory measures, and public awareness campaigns to address threats posed by the species. Targeted removal efforts, public education on handling and reporting sightings, and further research can also play a part in mitigating threats.

Researchers from the Faculty of Natural Sciences at Juraj Dobrila University of Pula and the Institute of Oceanography and Fisheries in Split published the discovery in the open-access journal Acta Ichthyologica et Piscatoria.

Original source

Iveša N, Buršić M, Dulčić J (2025) Northernmost Mediterranean record of the silver-cheeked toadfish, Lagocephalus sceleratus (Actinopterygii, Tetraodontiformes, Tetraodontidae). Acta Ichthyologica et Piscatoria 55: 77-81. https://doi.org/10.3897/aiep.55.146945

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Airport dogs can prevent invasive pests from entering new territories

Biosecurity inspectors and detector dogs are an effective combination in combatting the spread of invasive species.

Researchers at the University of Melbourne’s Centre of Excellence for Biosecurity Risk Analysis (CEBRA) have highlighted biosecurity risks posed by air passengers and emphasised the value of border interventions such as detector dogs in mitigating these threats.

Published in the open-access journal NeoBiota, the study focused on domestic air travel into Tasmania, Australia, an island state with an especially low pest presence due to its geographic isolation.

Airport sign reading 'biosecurity Tasmania'

Researchers utilised an extensive database of more than 66,000 biosecurity risk interceptions from over 6 million passengers entering Tasmania from mainland Australia. With this, they applied advanced statistical modelling tools to assess how effective different interventions are at catching risky material at the border.

Their analysis found that air passengers pose a significant biosecurity risk, with pests potentially introduced via items like fruits, vegetables, and animal products carried in luggage.

To combat this risk, border interventions using biosecurity inspectors and detector dogs were found to be effective, both by encouraging voluntary declarations by passengers and detecting risk items that passengers failed to declare.

While biosecurity inspectors play a significant role, detector dogs are especially effective, detecting a higher rate of risky items and targeting undeclared materials that might otherwise go unnoticed. The presence of detector dogs substantially increased interception rates, including for items linked to the spread of the invasive fruit fly.

Airport sign reading 'Help protect out beautiful island - biosecurity acheckpoint'

Lead author Dr Nicholas Moran said: “Dogs being great at sniffing things out might seem obvious, but measuring precisely how effective different interventions are, what they capture, and how, is incredibly valuable information for biosecurity operations.

“Fruit flies are a serious risk to Tasmania, and many parts of the world. So, this work is about knowing what biosecurity interventions to deploy, and where is best to deploy them to reduce the risk of outbreaks.”

The study is a part of the “Risk Analysis of Tasmanian Border Inspection Approaches and Procedures” project, conducted by CEBRA with Biosecurity Tasmania. The two-phase project investigated the invasive risk of five pest species that are common across Australia’s mainland but are not currently found in Tasmania.

Original study

Moran NP, Hanea AM, Robinson AP (2025) Border biosecurity interceptions for air passengers – assessing intervention methods and analytic tools. NeoBiota 97: 161-178. https://doi.org/10.3897/neobiota.97.141784

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Flamboyant and lethal: unveiling the lionfish invasion of the Mediterranean Sea

So-called ‘devil firefish’ are taking over new waters with little resistance from native species.

Research from Wageningen University a n d Research, the Netherlands, reveals invasive lionfish are rapidly expanding their territory in the Mediterranean sea, causing severe ecological damage.

Published in the open-access journal NeoBiota, the study shows the lionfish species Pterois miles – known as the devil firefish – has established presence in the eastern Mediterranean, with observations now extending to colder waters previously thought to be unsuitable for the species.

A map of the Mediterranean Sea, with dots showing the first sighting of invasive lionfish. It shows a gradual eastwrd progression of lionfish sightings over time. — Map of years of first sighting of *Pterois miles* by dive centres. Credit: Bottacini et al.

Originating from the Indo-Pacific region, the lionfish species Pterois miles and Pterois volitans are regarded as the most successful and lethal invasive fishes in marine ecosystems, with the capacity to drastically affect local fish communities and biodiversity in invaded areas.

The invasion of Pterois miles in the Mediterranean Sea began around ten years ago. Genetic studies reveal the invasive fish originated from the Red Sea and likely entered through the Suez Canal.

The beautiful but deadly devil firefish. Credit: Kora27 via Wikimedia Commons.

Lionfish are generalist predators and impact ecosystems by preying extensively on local fishes, including endemics of high conservation value. As they are unaccustomed to lionfish, native prey species usually do not flee from this new predator.

“After years studying these predators, I find it amazing how they can easily adjust to so many different environments and be successful in areas so different from where they evolve.”

“It is always impressive to see how such a flamboyant and–to us–conspicuous predator can approach its prey without being noticed”
The study’s lead author, Davide Bottacini.

The fin spines of Pterois miles are highly venomous. A sting can cause extreme pain, sickness, convulsions, minor paralysis, and breathing difficulties in humans. Immediate emergency medical attention is recommended for anyone stung by the species.

By reviewing existing scientific data, researchers identified gaps in current understanding of the lionfish’s interactions with Mediterranean ecosystems.

They suggest that, while they consider the eradication of invasive lionfish impossible, tackling questions such as the community-level impact of them in the Mediterranean, and the evolutionary and learned responses in prey, will add to the body of knowledge on the best documented invasion in marine ecosystems.

Three maps of dive centre respondents and lionfish sightings on the Meditteranean Sea coat showing a gradual eastwrd progression of sightings. — Maps of dive centre respondents and lionfish sightings. Credit: Bottacini et al.

Such information provides insights vital for biodiversity conservation, with practical implications for policy makers aiming to devise efficient mitigation plans.

Citizen science initiatives for tracking and reporting lionfish sightings are encouraged to provide valuable data that supports ongoing research efforts. Such community involvement is essential for enhancing understanding of the invasion dynamics and devising effective control measures.

Original source

Bottacini D, Pollux BJA, Nijland R, Jansen PA, Naguib M, Kotrschal A (2024) Lionfish (Pterois miles) in the Mediterranean Sea: a review of the available knowledge with an update on the invasion front. NeoBiota 92: 233–257. https://doi.org/10.3897/neobiota.92.110442

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First database of the impacts of invasive plants in Europe

Freely accessible, the database provides useful contextual information and identifies key gaps in European invasive-plant research.

A team of experts has created the first database of field studies on the impacts of invasive plants on native species, communities and ecosystems in Europe.

The dataset comprises 266 peer-reviewed publications reporting 4,259 field studies on 104 invasive species across 29 European countries. It is the first harmonised database of its kind at continental scale, and is freely accessible to the scientific community for future studies. Notably, one third of the studies focused on just five species that invade several central European countries.

Japanese knotweed (*Reynoutria japonica*) in a garden in Brastad, Lysekil Municipality, Sweden.

Published in NeoBiota, the project was mainly funded through the European Regional Development Fund (SUMHAL, LIFEWATCH, POPE). It was executed by researchers from the Spanish institutes, E s tación Biológica de Doñana, Universidad de Sevilla, Instituto Pirenaico de Ecología and Universidad de Alcalá, as well as the University of Fribourg, Switzerland.

The comprehensive database indicates that invasive plants impact other plants, animals and microbes, all trophic levels (herbivores, parasites, plants, pollinators, predators, omnivores, decomposers and symbionts) and numerous ecosystem processes.

Map of locations (red dots) of field studies on the ecological impacts of invasive plant species in Europe. Credit: Vilà et al.

More than half of the studies were conducted in temperate and boreal forests and woodlands and temperate grasslands. Major knowledge gaps are found in Baltic and Balkan countries, in desert and semi-arid shrublands, subtropical forests and high mountains.

Prof. Montserrat Vilà, coordinator of this task, highlights that the database provides information on whether the invasive species increase, decrease or have a neutral effect on the ecological variable of study. This allows investigation into the circumstances in which the invader has contrasting effects.

Himalayan balsam (*Impatiens glandulifera*). Credit: Guptaele via Wikimedia Commons, CC BY-SA 4.0.

The database will be updated as new field studies on the ecological impacts of invasive species are published. “We hope for more studies on species that are still locally rare and with restricted distribution,” Prof. Montserrat Vilà says, “this database is of interest for academic, management and policy-related purposes.”

The PLANTIMPACTSEUROPE database can be accessed at: https://figshare.com/s/0a890d22bf5632fe5cb5

Research article:

Vilà M, Trillo A, Castro-Díez P, Gallardo B, Bacher S (2024) Field studies of the ecological impacts of invasive plants in Europe. NeoBiota 90: 139-159. https://doi.org/10.3897/neobiota.90.112368

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Did European insects invade the world because settlers carried plants?

Researchers suggest European insect invaders may be so abundant due to colonial introductions of non-native plants.

Insects are among the most prolific and successful invaders of new habitats, but not all regions are equal in the numbers of insects that have spread beyond their borders.

Flows of non-native insects between N. America, Europe, and Australasia. Numbers are the total count of species established from donor to recipient.

European insects, in particular, stand out as highly successful invaders into other world regions. Why? Biologists have long understood that species are spread through international trade: insects are frequent stowaways in trade goods, and the value of international trade between world regions can be a good predictor of how many non-native species are exchanged.

However, recent research led by Dr. Rylee Isitt of the University of New Brunswick, and published in the journal NeoBiota, shows that after accounting for patterns of international trade, the number of insects that have spread from Europe into North America, Australia, and New Zealand far exceeds expectations.

Since patterns in international trade can’t explain these insect invasions, the researchers looked for other potential explanations. It’s possible that European insects are simply more numerous or better invaders than their North American or Australasian counterparts. However, Dr. Isitt and his collaborators didn’t find evidence for that – at most, there are only slightly more European species with the capacity to invade compared to North American and Australasian species.

Another possibility is North American and Australasian habitats are easier to invade than European ones. But prior research has shown that Europe has been heavily invaded by Asian insects, suggesting that it is no more resistant to invasion than North America or Australasia.

Instead, Dr. Isitt and collaborators have proposed that the abundance of European insect invaders may be a result of deliberate introductions of non-native plants into Europe’s colonies. Plants introduced into European colonies could have promoted the spread of European insects into North America and Australia by two different means.

First, insects may have been introduced along with the plants. Second, introduced plants may have provided suitable food and habitat for subsequent arrivals of non-native insects, who might have otherwise found the native flora to be unpalatable or unsuitable as a habitat.

Cumulative discoveries (observed and modelled) and establishments (modelled) of non-native insects exchanged between Europe (EU), North America (NA), and Australasia (AU) versus cumulative import value (inflation-corrected to 2020 British pounds sterling, billions), 1827–2014. Alternating background shading indicates decadal increments, with shading omitted prior to the 1940s for clarity.

Although the researchers haven’t completely resolved the mystery of the overabundance of European insects, they have ruled out several possibilities, leaving the connection to introduced plants as the prime suspect. The next steps? Determining to what extent European insects spread through introduced plants compared to insects from other world regions.

Because invasive species are reshaping our world, we need to understand how they move and establish. Evidence is mounting that trade in plants and plant products is responsible for a large proportion of insect invasions. If the researchers’ hypothesis is correct, the spread of European insects may be a remarkable example of the unintended consequences of deliberate plant introductions.

Research article:

Isitt R, Liebhold AM, Turner RM, Battisti A, Bertelsmeier C, Blake R, Brockerhoff EG, Heard SB, Krokene P, Økland B, Nahrung HF, Rassati D, Roques A, Yamanaka T, Pureswaran DS (2024) Asymmetrical insect invasions between three world regions. NeoBiota 90: 35-51. https://doi.org/10.3897/neobiota.90.110942

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Soil carried on sea freight loaded with dangerous pests and diseases

Soil collected from the external surfaces of sea freight was found to support live microorganisms, worms, seeds and insects, including various regulated biosecurity organisms.

Often introduced unintentionally by human activities, invasive alien species can outcompete and overwhelm native flora and fauna, driving species to the brink of extinction and disrupting the balance of ecosystems. Understanding why exactly they establish in new locations and how they got there in the first place is crucial if we are to mitigate their destructive effects. Unfortunately, there isn’t enough research on this, and the answers might not always be straightforward.

A research team from AgResearch and Better Border Biosecurity (B3) investigated the biological risk posed by soil on the external surfaces of sea freight such as shipping containers or used machinery at sea ports in New Zealand. With their work, the researchers hope to facilitate the assessment of relative biosecurity risks between different introduction pathways and contribute to the development of more efficient measures against them.

The team found soil on most types of sea freight, irrespective of origin, with all soil likely to vector microbes, including plant pathogens. The amount of soil recovered from a single sea container was 5.3 kg, while the overall mean weight collected from sea freight was 417g, with most of the soil found on the underside of sea freight.

“While the presence of soil is perhaps not surprising, the presence of live bacteria, fungi, worms, seeds and insects associated with the soil was of greater concern. Various regulated biosecurity organisms were recovered from the samples, including plant-parasitic worms, seeds, insects and spiders that were not recorded as being present in New Zealand,” says Mark McNeill of AgResearch, who led the study.

Seeds of *Euphorbia prostrata*, a new record to New Zealand, were found on sea freight. Photo by Stefan.lefnaer under a CC BY-SA 4.0

“Not only does the spread of exotic species through these networks represent significant environmental, economic and social costs to natural and agricultural environments if invasive alien species were to establish, a loss of biodiversity is also an expected consequence of invasive alien species establishment. For islands, the implications can be significant, as they have high levels of endemism and invasive alien species establishment can lead to extinction of species as well as biodiversity declines,” the researchers write in their paper, which was published in the open-access journal NeoBiota.

Compared to a previous study on contaminated footwear carried in luggage by international airline passengers, the number and diversity in soil on sea freight was smaller than soil transported in more protected environments (e.g., footwear in luggage). This showed that biosecurity risk can vary with pathway. However, prioritising one soil pathway over another according to the risks they present, and differentially allocating resources is problematic, because the relative risk is dynamic, dictated by factors such as new pests or diseases entering the respective pathways.

Unwelcome guests: International tourism and travel can be a pathway for introducing invasive species

Even so, the researchers suggest that contaminated sea freight is an important introduction pathway for exotic species. The establishment of such species can be prevented by cleaning containers prior to departure, inspection at the border, and further cleaning where required.

Research article:

McNeill MR, Phillips CB, Richards NK, Aalders LT, van Koten C, James TK, Young SD, Bell NL, Laugraud A (2023) Defining the biosecurity risk posed by soil found on sea freight. NeoBiota 88: 103-133. https://doi.org/10.3897/neobiota.88.98440

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