invasive species

Australian winged wētā population in Auckland increasing, posing a threat to native invertebrates

In a peer-reviewed study published in the Journal of Orthoptera Research, the insect has been traced back to its origin in Queensland.

A fearsome-looking insect commonly referred to as “winged wētā” may look like a flying wētā, but it is not a wētā at all. It belongs to the family of the raspy crickets, which is not native to New Zealand. Like all of its family members, it has the ability to secrete silk from its mouth parts, which it uses to build shelters in foliage.

A close-up photo of a brown cricket resting on a green fern leaf. — Adult male winged wētā *(Pterapotrechus salomonoides)* in its natural habitat. Photo by Danilo Hegg

The “winged wētā” was first detected in Auckland in 1990. Within thirty years, it had expanded its range north to Cable Bay, Northland; east to Coromandel Peninsula, and south to Raglan, Waikato. While sightings in New Zealand became more and more numerous, the insect remained unidentified. New Zealand entomologist Danilo Hegg recently travelled to Queensland, Australia, to trace the “winged wētā” back to its population of origin and put a name to the species. In a peer-reviewed study now published in the Journal of Orthoptera Research, Hegg showed that the insect originates from the montane rainforests south of Brisbane, at the border of Queensland and New South Wales.

A map of Australia and New Zealand highlighting specific locations in Queensland and New South Wales, including Brisbane, Tamborine Mountain, and Auckland. — Collection localities in New Zealand and Australia.

“The insect is heavily built, has relatively short wings, and is a poor flyer,” says Hegg. “While Australian butterflies do occasionally reach our shores carried by westerly winds, the 2,300km journey across the Tasman Sea is almost certainly too much for the winged wētā. It is highly unlikely that it would have reached New Zealand by natural means”. Australian insects carried by the wind may land anywhere between Cape Reinga and Rakiura / Stewart Island. The fact that the “winged wētā” was first detected in Auckland, New Zealand’s largest import hub, only adds weight to the hypothesis of an accidental introduction by anthropogenic means.

Not only has the “winged wētā” been expanding its range in New Zealand; it has also been building up numbers. Its population density has at least quintupled in Auckland during the past twelve years. And like many other invasive species, it appears to be found in higher numbers in its new territory than in its country of origin. “In Queensland, I could spend a night out and find one or two individuals at most. In Auckland, I was able to capture seven specimens in a two-hour walk” says Hegg.

A photo of two crickets nestled together inside curled green leaves. — Nymphs of winged wētā *(Pterapotrechus salomonoides)* in rolled leaves held together by silk strands

The “winged wētā” is an omnivore and an agile hunter. Strictly nocturnal, it prowls in the foliage in trees and pounces on any invertebrate that is small enough for it to tackle. Observations conducted in captivity and in the wild have shown that the “winged wētā” preys on just about anything that moves at night. Including juvenile Auckland tree wētā, one of New Zealand’s largest insects.

A close-up photo of a brown cricket resting on a green leaf and holding insect wings in its mandibles. — A winged wētā *(Pterapotrechus salomonoides)* Nymph with winged termite (Schedorhinotermes sp.) prey.

Given its high population density and its predatory habits, there are concerns the invasive insect could have an impact on New Zealand’s native invertebrate wildlife. “There is still a lot we don’t know” says Hegg “we need to study its diet in the wild, and we need to understand whether the winged wētā is also taking hold in intact native forest habitats, or only in urbanised areas, where the majority of the sightings are. But it poses a threat that needs to be taken seriously”.

New Zealand’s invertebrates are already being decimanted by introduced rodents, mustelids, hedgehogs, cats and wasps. The Australian winged wētā is only going to add to their woes.

Research article:

Hegg D (2025) An Australian raspy cricket established in New Zealand, Pterapotrechus salomonoides (Orthoptera, Gryllacrididae), with notes on ecology and first description of the male. Journal of Orthoptera Research 34(1): 77-94. https://doi.org/10.3897/jor.34.134391

Pensoft joins new Horizon Europe project to help tackle terrestrial invasive alien species

Pensoft will play a vital role in public awareness, engagement and promoting effective strategies for monitoring and managing IAS.

*The Chinese muntjac* *(Muntiacus reevesi)* *is an invasive alien species for Europe with established populations across the western part of the continent*. *Photo by Mario Shimbov (Pensoft).*

As one of the partners in charge of maximising the project’s impact, Pensoft will work on OneSTOP’s visual branding, communication, dissemination and exploitation, and the development of a data management plan for the project.

Invasive alien species (IAS) pose one of the most significant threats to global biodiversity, contributing to species extinctions, ecosystem degradation, and economic losses exceeding $400 billion annually.

To tackle this, the EU enforces Regulation (EU) 1143/2014 and the Biodiversity Strategy for 2030, aiming to prevent IAS introduction, enhance early detection, and manage their spread. Member States coordinate efforts with scientific support and citizen engagement to minimise their impact and protect Europe’s biodiversity. Addressing this urgent challenge, the EU Horizon project OneSTOP has officially launched as part of a coordinated European effort to combat biological invasions in terrestrial environments.

Comprehensive Approach to Tackling Invasive Alien Species

OneSTOP is one of two ambitious projects funded under the Horizon Europe programme, the other being GuardIAS, which focuses on marine and freshwater habitats. The two collaborative initiatives held their joint official kick-off meeting in January at the Joint Research Centre in Ispra, Italy. Together, these projects aim to develop innovative solutions for detecting, preventing, and managing invasive alien species across all ecosystem realms.

Coordinated by Dr Quentin Groom from Meise Botanic Garden, Belgium, and Prof Helen Roy from the UK Centre for Ecology and Hydrology, OneSTOP will integrate advanced scientific research, cutting-edge detection technologies, and policy-driven strategies to enhance biosecurity across Europe.

*The ОneSTOP project consortium at the project’s kick-off meeting held on 20-24 January 2025 in Ispra, Italy.*

The project is structured around four key objectives:

Improve species detection and response time by incorporating computer vision, environmental DNA (eDNA) analysis and citizen science initiatives.
Facilitate swift action against invasive species threats by openly sharing data in international standards for biodiversity data with stakeholders who need it.
Support policy-makers in making informed decisions about where and how to allocate resources for invasive species management by developing data-driven systems.
Ensure stakeholder collaboration and knowledge exchange by implementing Living Labs at the regional level and an international policy forum, thereby encouraging socio-political action.

OneSTOP aligns with the European Alien Species Information Network (EASIN) mission to protect EU biodiversity by improving IAS management through advanced biosecurity technologies and enhanced data integration. By fostering collaboration with the Joint Research Centre (JRC) and supporting Member States with innovative tools, the project strengthens the EU’s capacity to detect, respond to, and mitigate IAS threats in line with existing regulations.

Pensoft’s role in OneSTOP

As the leader of Work Package 1, Pensoft is responsible for shaping OneSTOP’s visual identity and developing a comprehensive strategy for communication, dissemination, and impact. This includes crafting a data and knowledge management plan to ensure the project’s findings are effectively shared and utilised. By fostering collaboration with key biosecurity networks, these efforts will strengthen OneSTOP’s long-term influence.

A key part of this work is to raise awareness about invasive alien species (IAS) and their pathways, ensuring that policymakers, researchers, and the public understand their impact and the importance of prevention. Pensoft will contribute to translating complex scientific findings into accessible content—including infographics, policy briefs, and interactive visualisations—to engage policymakers, researchers, and the public. These efforts will ensure that IAS knowledge is effectively shared, fostering collaboration and informed decision-making across sectors. Knowledge transfer materials will be shared through various channels, including OneSTOP’s five Living Labs across Europe, where stakeholders will be actively engaged in outreach and citizen science initiatives.

Pensoft will play a vital role in strengthening public awareness, fostering engagement, and promoting effective strategies for monitoring and managing IAS.

International Consortium

The project brings together twenty international partners from fifteen countries operating in various sectors, ultimately contributing with diverse expertise:

Meise Botanic Garden – Belgium
Aarhus University – Denmark
UK Centre for Ecology & Hydrology – United Kingdom
Biopolis – Portugal
Coventry University – United Kingdom
The Cyprus Institute – Cyprus
Research Institute for Nature and Forest – Belgium
Institute of Botany of the Czech Academy of Sciences – Czech Republic
Lincoln University – New Zealand
Platform Kinetics – United Kingdom
Pensoft Publishers – Bulgaria
Stellenbosch University – South Africa
University of Exeter – United Kingdom
University of Vienna – Austria
Greenformation – Hungary
Helmholtz Centre for Environmental Research – Germany
Ovidius University of Constanta – Romania
Natural Resources Institute Finland – Finland
The Binary Forest – Belgium
Experimental Station of Arid Areas of the Spanish National Research Council – Spain

The OneSTOP project website is coming soon!

For more information visit the OneSTOP project website, and make sure to follow the project’s progress via our social media channels on BlueSky and LinkedIn.

The human dimensions of biological invasions – involving stakeholders in addressing invasive species

Can the knowledge and experience of recreational anglers in Iceland help us understand how far the invasive flounder has spread in the country?

Guest blog post by Theresa Henke

For centuries, all kinds of species have been transported by humans around the globe, allowing them to cross the boundaries of their native range and settle in new ecosystems. Over the past decades the numbers of these introduced species and the impacts they cause have been continuously increasing. Biological invasions nowadays represent one of the biggest threats to biodiversity worldwide.

Humans are and have always been an essential part of biological invasions and in order to fully understand the issue and how to tackle it, we need to understand and include the human dimensions in our research.

My research on European flounder in Iceland began in 2017 when I was writing my Master’s thesis. The flounder is a flatfish species that had been officially documented in the country since 1999 but not much was known on its impacts. In my thesis I looked at the flounder through ecological lenses, trying to identify how the presence of the flounder affects other species. Living in a small community in the Westfjords of Iceland during this time, I got to meet many local people who shared their personal stories, experiences and knowledge with me in every-day conversations. I truly enjoyed these conversations and learning about the species I study from different perspectives beyond the academic settings. These exchanges sparked my interest in exploring the human dimensions of biological invasions and, looking back, have really shaped my academic path going forward.

In our recently published NeoBiota study “Have you seen this fish? – Important contribution of stakeholder observations in documenting the distribution and spread of an alien fish species in Iceland” we wanted to explore how the knowledge and experience of recreational anglers in Iceland can help us understand how far the flounder has spread in Iceland. The flounder in Iceland had only received little scientific interest before and the available information was limited and scattered between different institutions and scientists. Recreational anglers, on the other hand, who chase after native salmon, trout, and char in the Icelandic rivers and lakes, often encounter the flounder.

In 2019, we asked anglers in Iceland to take part in an online survey, where we asked them different questions about the flounder, including where in Iceland they have seen or caught it. We then compared locations named by anglers to the locations that were available from different databases of the Marine and Freshwater Research Institute of Iceland. The locations we received included data collected during scientific surveys and research projects done by the institute as well as observations that were reported to the institute by the public (mostly recreational anglers and commercial fishermen).

Our goal was to evaluate whether observations made by stakeholders, in this case the recreational angling community in Iceland, could be a good source of additional information for monitoring of an alien fish species. Collecting information on the distribution and spread of an alien species is a very important step in addressing biological invasions but is often underdeveloped because not enough resources (i.e. money, time, scientists…) are made available.

Theresa Henke holding a 43-cm flounder in Eyjafjörður.

We have shown that neither source offers a perfect solution to the monitoring of the flounder in Iceland. But we show that each of the sources has their own advantages and disadvantages and by combining them, we are able to get a much clearer picture of where in Iceland the flounder currently occurs and how fast it spread in the early years. Information that was shared by stakeholders, whether it was in our study or to the databases of the Marine and Freshwater Research Institute, played a big role in better understanding the flounder in Iceland.

The interactions with the recreational angling community in Iceland during my PhD have taught me a lot about the flounder in Iceland but even more about my own approach to science. I think as scientists, we should more often take a step outside of our academic bubble and take a look at the issue we are studying from the perspectives of the public and other stakeholders. In the case of biological invasions, we can learn a lot from those who are directly confronted by an invasive species, regardless of whether they have a scientific degree or not.

Research article:

Henke T, Bárðarson H, Thorlacius M, Ólafsdóttir GA (2025) Have you seen this fish? Important contribution of stakeholder observations in documenting the distribution and spread of an alien fish species in Iceland. NeoBiota 97: 67-90. https://doi.org/10.3897/neobiota.97.132365

Assessing the impact of invasive plants on ecosystems: a new framework

By combining several new advancements, the framework will aid in the management of plant invasions.

Invasive plant species pose a major threat to biodiversity and ecosystem health worldwide. However, predicting the exact impact of these invasions is challenging due to the complexity of interactions between invading species, native communities, and impacted ecosystems.

To combat this issue, researchers from the University of Freiburg and Justus Liebig University Giessen have developed a framework to better assess the impact of invasive plant species on ecosystems.

Outlined in a study published in the open-access journal NeoBiota, the framework combines new technologies and techniques to learn and predict how invasive plants alter ecosystems over time and in different environments.

Animated model visualisation of spatial-temporal dynamics of invader impacts. Click here to download a detailed explanation of the model.

The new framework integrates several modern advancements:

Environmental mapping: Progress in remote sensing and ecological monitoring allow researchers to capture detailed information about the environmental conditions of invaded areas. Drones, satellites, and advanced sensory networks can be used to create detailed ecosystem maps, which show how invasive species interact with their environment.

Functional tracers: These are specific indicators that reflect changes in ecosystem functions caused by invasive species. For example, researchers can track the impact of nitrogen-fixing invasive plants on ecosystems using nitrogen isotopes.

Spatio-temporal modelling: By combining environmental data with new modelling techniques, such as AI, researchers can create detailed models showing the spread and impact of invasive species on ecosystems over time. Such models can predict how changes in environmental conditions, such as climate change, might influence an invasive species’ success.

Infographic showing the mechanisms that determine the impact of invasive plants on ecosystems. — Mechanisms determining plant invasion impact.

Beyond scientific analysis, novel technologies also facilitate communication of ecological impacts, as the authors demonstrate in an animated 3D-video visualisation.

“The framework we’ve introduced offers researchers deeper insights into how invasive plant species interact with their environments, enabling more targeted management to lessen their ecological impact. We advocate for stronger collaboration between ecologists and technical experts to refine and expand these methods.

“Going forward, further research and integration of the wide range of recent methods and tools are needed to enhance the framework’s effectiveness.”
The research team behind the new framework: Christiane Werner, Christine Hellmann and André Große-Stoltenberg.

Original source

Werner C, Hellmann C, Große-Stoltenberg A (2024) An integrative framework to assess the spatio-temporal impact of plant invasion on ecosystem functioning. NeoBiota 94: 225-242. https://doi.org/10.3897/neobiota.94.126714

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The silent invasion: how termites threaten homes worldwide

As climate patterns shift, global cities may soon find themselves under siege by these tiny yet destructive pests.

As climate change continues its relentless march, the world faces not only rising temperatures and extreme weather, but also an insidious threat to our homes: invasive termites. And the bill could be steep – invasive termites currently cost over 40 billion USD annually.

In a new study published in the open-access journal Neobiota, PhD student Edouard Duquesne and Professor Denis Fournier from the Evolutionary Biology & Ecology lab (Université libre de Bruxelles) unveil the unsettling reality of invasive termites’ potential expansion into new territories.

Their research reveals that as temperatures rise and climate patterns shift, cities worldwide, from tropical hotspots like Miami, Sao Paulo, Lagos, Jakarta or Darwin to temperate metropolises like Paris, Brussels, London, New York or Tokyo, could soon find themselves under siege by these tiny yet destructive pests.

A man with a headtorch inspects the damages caused by Coptotermes gestroi termites on a house wall. — Adolfo Cuadrado, a termite infestation specialist at Anticimex, meticulously inspects the damages caused by *Coptotermes gestroi* on a house wall. © David Mora: https://www.pasiontermitas.com.

But how do termites, typically associated with tropical climates, find their way into cities far beyond their natural habitat? The answer lies in the interconnectedness of our modern world. Urbanisation, with its dense populations and bustling trade networks, provides the perfect breeding ground for termite invasions.

Moreover, the global movement of goods, including wooden furniture transported by private vessels, offers unsuspecting pathways for these silent invaders to hitch a ride into our homes.

“A solitary termite colony, nestled within a small piece of wood, could clandestinely voyage from the West Indies to your Cannes apartment. It might lurk within furniture aboard a yacht moored at the Cannes Film Festival marina.”

“Mating is coming. Termite queens and kings, attracted by lights, may initiate reproduction, laying the groundwork for new colonies to conquer dry land.”
Researchers Edouard Duquesne and Denis Fournier.

Duquesne and Fournier’s research emphasises the need for a paradigm shift in how we approach invasive species modelling. By integrating connectivity variables like trade, transport, and population density, their study highlights the importance of understanding the intricate interactions that facilitate termite spread.

Workers and soldiers of the invasive termite Reticulitermes. — Workers and soldiers of the invasive termite *Reticulitermes*. © David Mora: https://www.pasiontermitas.com.

In light of these findings, the researchers urge swift action from policymakers and citizens alike. Major cities, regardless of their climate zone, must implement strict termite control measures to protect homes and infrastructure.

“Citizens can play a crucial role by leveraging technology, such as AI-assisted apps like iNaturalist, to detect and report potential termite sightings, turning ordinary residents into vigilant guardians of their environment,” say the researchers.

“As we confront the challenges of a rapidly changing climate, awareness and proactive measures are our best defence against the creeping menace of invasive termites,” they conclude.

Original source

Duquesne E, Fournier D (2024) Connectivity and climate change drive the global distribution of highly invasive termites. NeoBiota 92: 281-314. https://doi.org/10.3897/neobiota.92.115411

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Melting glaciers provide new ground for invasive species

A case study on the island of South Georgia.

Invasive species spread through human activities are one of the main causes of the ongoing biodiversity crisis.

Even on South Georgia, a remote island located in the very south of the Atlantic Ocean, exotic species are present. Many of which were inadvertently introduced by whalers and sealers in the 19^th and early 20^th century.

The invasive carabid ground beetle, Merizodus soledadinus, is present on sites that have been recently exposed by melting glaciers.

In a new study published in the open-access journal Neobiota and funded by Darwin Plus, researchers explored how living organisms colonise new ground provided by melting glaciers.

Like other cold regions of the world, South Georgia is losing its glaciers because of climate change, leaving behind large areas of newly uncovered bare ground.

Invasive annual meadow grass colonising ground only a few years after the glacier disappeared.

Researchers surveyed the foreland biodiversity of six glaciers, creating an inventory of the flora and fauna that colonise forelands at different stages of glacial retreat.

A survey site near a former whaling station (Grytviken).

They found that, just a few years after bare ground is exposed by a glacier melting, pioneer plants arrive, progressively covering more ground with time, followed by an increasing number of species.

Native and exotic plants, as well as invertebrates, take advantage of this opportunity. Surprisingly, two temperate plant species from the Northern Hemisphere, annual meadow grass and mouse-ear chickweed, colonise sites faster than any other species.

The team suggests their results indicate invasive species will likely spread on South Georgia as fast as glaciers are retreating. Whether this has or will have negative consequences on local species needs to be investigated to help protect this unique ecosystem.

Original Source

Tichit P, Brickle P, Newton RJ, Convey P, Dawson W (2024) Introduced species infiltrate recent stages of succession after glacial retreat on sub-Antarctic South Georgia. NeoBiota 92: 85-110. https://doi.org/10.3897/neobiota.92.117226

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Listen to the trees: a detective work on the origin of invasive species

An attempt to explore the history of the spread of four non-indigenous invasive tree species in one of the most important Hungarian forest-steppe forests of high conservation value.

Guest blog post by Arnold Erdélyi, Judit Hartdégen, Ákos Malatinszky, and Csaba Vadász

Today, almost everyone is familiar with the term “biological invasion”. Countless studies have been carried out to describe the various processes, and explore the cause and effect, and several methods have been developed in order to control certain invasive species. However, one of the biggest puzzles is always the question of how it all happened. It is not always easy to answer, and, in general, the smaller the area, the more difficult or even impossible it is to answer. In the course of our work, we attempted to explore the history of the spread of four, non-indigenous invasive tree species in one of the most important Hungarian forest-steppe forests of high conservation value, the Peszér Forest (approximately 1000 ha). Last week, we published our study in the journal One Ecosystem.

An open formation of the Eurosiberian steppic woods with Quercus spp., a priority natural habitat type of Community interest under the European Union’s Habitats Directive

The Far Eastern tree of heaven (Ailanthus altissima), as well as the North American black cherry (Prunus serotina), the box elder (Acer negundo) and the common hackberry (Celtis occidentalis) are among the worst invasive plant species in Hungary. They are also responsible for serious conservation and economic problems in the Peszér Forest.

Invasion of tree of heaven (top left) and common hackberry (top right) in poplar stands, carpet of seedlings of black cherry (bottom left), and monodominant stand of box elder, regrown from stump after cutting (bottom right)

Historical reconstructions of the spread of invasive species are most often based on only one, or sometimes a few aspects. We used six approaches simultaneously:

we reviewed the published and grey literature,
extracted tree species data from the National Forest Database since 1958,
conducted a field survey with full spatial coverage (16,000 survey units (25×25 m quadrats)) – instead of sampling,
recorded all the largest (and presumably the oldest) individuals for annual ring counts,
performed hotspot analyses on the field data
collected local knowledge.

Cutting down the oldest common hackberry trees in order to count the annual rings from trunk discs

Our results show that each approach provided some new information, and without any of them the story revealed would have been much shorter and more uncertain. We have also highlighted that at the local level, the use of one or two aspects can be not only inadequate but also misleading.

From the literature it was possible to determine the exact place and date of the first occurrence of the tree of heaven and the black cherry. However, in the case of black cherry, for example, it was only possible to piece together the circumstances of the first plantings by combining three different sources. The first occurrences of box elder were found in forestry data. Finally, in the case of the common hackberry, searching for old individuals and determining their age gave the best results.

Common hackberry in the Peszér forest according to the recent forestry data (2016) and the field survey (2017-2019). The difference is clear: in the official forestry database, the tree species is underrepresented several times over

A well-explored story of a biological invasion can go a long way in making more and more people understand that controlling these non-indigenous species can only be beneficial. On the other hand, it can also help to strengthen conservation efforts, for example by increasing the volunteer workforce, which can be a major factor in the reduction of certain species. We hope that our work and the approaches we have taken will serve as a good model for exploring other invasion stories around the world.

Winter snapshot from the Peszér Forest, a diverse forest edge habitat along an inner road.

Research article:

Erdélyi A, Hartdégen J, Malatinszky Á, Vadász C (2023) Historical reconstruction of the invasions of four non-native tree species at local scale: a detective work on Ailanthus altissima, Celtis occidentalis, Prunus serotina and Acer negundo. One Ecosystem 8: e108683. https://doi.org/10.3897/oneeco.8.e108683

Hundreds of weeds found illegally advertised online in Australia

A research team led by Jacob Maher discovered thousands of online advertisements for weeds that are prohibited in Australia due to their harmful impact on the country’s environment and agriculture.

Hundreds of weeds have been found advertised on a public online marketplace in Australia. Cacti and pond plants were among the most frequently advertised illegal weed species. These weeds are prohibited in Australia due to their harmful impact on the country’s environment and agriculture. Despite this, a research team led by Jacob Maher discovered thousands of online advertisements for these weeds. Their study is published in the open access journal NeoBiota.

Water hyacinth, a notorious invader that was found traded online.

Trade of ornamental plants, the kind grown in homes and gardens, is the major way weeds are introduced to new places. Some ornamental plants can make their way into the environment and become invasive, negatively impacting native species and agriculture. Increasingly, plants are traded on the internet, allowing a wide variety of plants to be introduced to more distant places. A lack of surveillance and regulation of this trade has resulted in the wide trade of invasive species.

In response, scientists from the University of Adelaide have utilised specialised software called ‘web scrapers’ to monitor trade on public classifieds websites. These web scrapers automate the collection of online advertisements. This allowed the researchers to detect thousands of advertisements for weeds over a 12-month period.

Opuntia, a notorious invader that was found traded online.

Despite Australia’s laws banning the trade of harmful weeds, advertisements were observed across the country. Some of the weeds advertised were associated with uses by traders, including food and medicine. The most popular uses were associated with pond and aquarium plants such as filtering water and providing fish habitat.

The researchers recommend that governments adopt web scraping technology to assist in regulating online trade of plants. They also highlight increasing public awareness and seeking cooperation from online marketplaces as solutions to this growing problem.

“Currently, these online marketplaces allow people to advertise and purchase invasive species, whether they are aware of it or not,” says Maher. “Regulation is needed, but we also need to cultivate awareness of amongst plant growers of this issues and we need help from marketplaces to regulate trade on their end.”

The technology developed in this study is now being utilised by biosecurity agencies in Australia to monitor and regulate the illegal trade of plants and animals online.

Original source:

Maher J, Stringham OC, Moncayo S, Wood L, Lassaline CR, Virtue J, Cassey P (2023) Weed wide web: characterising illegal online trade of invasive plants in Australia. NeoBiota 87: 45-72. https://doi.org/10.3897/neobiota.87.104472

Invasive species as biomonitors of microplastics in freshwater ecosystems?

Microplastics forming the disproportionate amount of plastic garbage, and catfish have become numerically dominant in some ecosystems thanks to their tolerance to pollution and anoxic environments.

Armored catfish (Pterygoplicthys spp.) and microplastics, as invasive species and emerging contaminants, respectively, represent two socio-environmental problems in the globalized world, since both have negative effects on faunistic communities and freshwater habitats, as well as on rural community fisheries and public health.

Non-native invasive species of armored catfish have become numerically dominant in some ecosystems, with efforts to eradicate them a seemingly endless task. Due to this, a possible scenario of biological homogenization in Mesoamerica can be expected, mainly given by the wide dispersion of the Pterygoplichthys species, added to the introduction of other non-native catfish species.

Photo: Miguel Ángel Salcedo. Drawing: Diana Ríos-Hernández.

The omnipresence of plastics in terrestrial and aquatic environments is caused by their excessive use and inadequate management of waste. The discarded plastics are fragmented, degraded, and dissolved by solar radiation, wind, and water, among other agents, to be incorporated into the food web in aquatic environments.

Microplastics found in the digestive tract of armed catfish (Pterygoplichthys spp.)

Both persist in the aquatic environment, microplastics forming the disproportionate amount of plastic garbage, and catfish thanks to their tolerance to pollution and anoxic environments, and their ability to survive for several hours breeding atmospheric oxygen. What is the relationship between the two? Microplastics, depending on their origin and composition, are sedimented in the wetlands, where they can be ingested by detritus feeders, such as armored catfish, mainly in areas where there is runoff or discharge of liquid waste.

In this context, we ask ourselves, can armored catfish be used as biomonitors of microplastics deposited in wetlands? Taking the above into consideration, the doctoral student Gabriela Angulo-Olmos under the guidance of the researchers Nicolás Álvarez-Pliego, Alberto J. Sánchez, Rosa Florido, Miguel Ángel Salcedo, Allan K. Cruz-Ramírez and Arturo Garrido Mora from the Laboratorio de Humedales, from the División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, decided to answer the aforementioned question based on the numerical dominance of armored catfish recorded in the aquatic ecosystems of the Metropolitan Area of Villahermosa (MAV) in the coastal plain of the Gulf of Mexico.

A) Study area; Metropolitan Area of Villahermosa. Map modified from INEGI (2021). B) La Pólvora lake (Satélite Airbus 2023).

The stomach contents of the specimens from a lake located in the MAV were reviewed and the results showed that all the specimens had consumed microfibers. This result corroborated that these organisms can ingest sedimented microplastics due to their benthophagous habits.

Microplastics. Image by Oregon State University under a CC BY-SA 2.0 license.

The use of armored catfish as a resource in the food industry has had positive results, but is still insufficient. Therefore, we propose that another option to control their populations is to subtract and use this organism to verify which are the most frequent and abundant emerging contaminants deposited in the bottoms of urban wetlands.

Research article:

Angulo-Olmos G, Alvarez-Pliego N, Sánchez AJ, Florido R, Salcedo MÁ, Garrido-Mora A, Cruz-Rámirez AK (2023) Microfibers in the gut of invasive armored catfish (Pterygoplichthys spp.) (Actinopterygii: Siluriformes: Loricariidae) in an urban lake in the floodplain of the Grijalva River basin, Mexico. Acta Ichthyologica et Piscatoria 53: 81–88. https://doi.org/10.3897/aiep.53.102643

Fighting the spread of the spotted lanternfly with a new data science tool

“The lydemapr package will aid researchers, managers and the public in their understanding, modelling and managing of the spread of this invasive pest,” says Dr. De Bona, the lead author of the study.

“Stomp, squash, smash” has been the accompanying soundtrack to the expansion of an odd-looking bug through the Eastern US. The spotted lanternfly, a large planthopper native to Asia, has been popularized in media outlets as the most recent enemy one ought to kill on sight.

Spotted lanternflies. Photo by Matthew Helmus

This charismatic insect was first discovered in the US in Berks county, Pennsylvania, in 2014, likely the result of an accidental introduction alongside shipments of landscaping materials. Since then, the invasive pest has spread throughout the country, fueled by its ability to hitch rides undetected on cargo and passenger vehicles, and aided by the widespread presence of one of its favorite food sources, the tree of heaven, another invasive in North America. As of 2023, it has been found in 14 US states.

Unfortunately, this species is not picky when it comes to the plants it consumes, favoring both crops and ornamentals, and showing a particular preference for cultivated grape. This dietary choice has impacted several wine-making areas throughout Pennsylvania and New York state, and is threatening important wine hubs on the Western coast of the US.

When it comes to controlling the spread of this pest, two of the main challenges for researchers and field managers alike are to 1) know where this species is today so that eradication campaigns can be targeted and 2) predict where it will be tomorrow, to invest in prevention practices. Both efforts rely on accurate and extensive knowledge of its past and present distribution.

Many state and federal agencies, as well as individual research institutions, have been involved in conducting surveys to detect this bug in the field. In addition, a campaign to raise public awareness has fostered the development of self-reporting tools citizens can use to track sightings of this insect. Unfortunately, given the different practices adopted by these parties, the data on the presence of spotted lanternfly are scattered and hard to access, which makes it harder to assess and manage its spread.

The need to put together a current, comprehensive, consistent and openly available dataset pushed researchers at Temple University to take action. A research group led by Dr. Matthew Helmus has been closely monitoring the spread of this invasive pest since its inception, contacting institutions and collecting data. In a recent work published in the journal NeoBiota, Dr. Helmus and Dr. Sebastiano De Bona, together with collaborators across several agencies, put together an anonymized and comprehensive dataset that collected all records of spotted lanternfly in the US to date. These records come from a plethora of sources, from control actions, citizen-science projects, and research efforts. The resulting dataset contains highly detailed data (at 1 km² resolution) with yearly information on the presence or absence of spotted lanternflies, the establishment status of this pest, and estimated population density, across over 650,000 observations.

“The lydemapr package will aid researchers, managers and the public in their understanding, modelling and managing of the spread of this invasive pest,” says Dr. De Bona, the lead author of the study.

The scientists hope that this package will make forecasting the spread of the spotted lanternfly easier and foster more effective collaboration between agencies and researchers.

Research article:

De Bona S, Barringer L, Kurtz P, Losiewicz J, Parra GR, Helmus MR. 2023. lydemapr: an R package to track the spread of the invasive Spotted Lanternfly (Lycorma delicatula, White 1845)(Hemiptera, Fulgoridae) in the United States. NeoBiota 85: 151–168, DOI: 10.3897/neobiota.86.101471

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