Assessments of alien species impacts are reliable to prioritize resources

Experts are consistent when assessing the economic, health and ecological impacts of alien species, find the scientists.

Original post by EBD-CSIC

An international collaboration led by the Doñana Biological Station (EBD-CSIC) has shown that experts are consistent when assessing the economic, health and ecological impacts of alien species. These assessments are therefore reliable to guide the prioritization of resources invested against biological invasions.

You can find the scientific article published in the open-access, peer-reviewed scholarly journal NeoBiota.

These results have a great impact on the management by national and international institutions, which have limited resources to fight against the growing and worrying increase of alien species invasions and the damage they caused to society and environment. 

Biological invasions annually cause huge food losses, disease transmissions, species extinctions and ecosystem perturbations. For these reasons, it is one of the biggest problems that humankind currently faces, and its relevance will alarmingly increase due to the extreme situations that climate change will expose society to.

The seriousness of this problem lies in the limited human resources available to fight against it, that force to prioritize its management. Here is where tools such as impact assessments play a key role. Assessments report the impact of invasive species in different areas, including economy, health and environment, and allow us to rank the most harmful species.

For instance, in aquatic ecosystems like the Ebro Delta in Spain, there are dozens of invasive alien co-occurring species that cause millions of economic losses and irreparable ecological damage.

Such is the case of the Zebra mussel, which affects irrigation; the apple snail that devours rice fields; and the blue crab causing the local extinction and declines of many native species.

“That’s why it is crucial to ensure that the results are not dependent on the assessors and to understand what factors affect discrepancies among experts,”

explains Rubén Bernardo-Madrid, lead author and researcher at Doñana Biological Station – CSIC.

One of the relevant aspects of this study is the quantification of the consistency of responses across assessors for a large number of invasive species of vertebrates, invertebrates and plants. In addition, the researchers have studied multiple protocols focused on different aspects, providing a global view of this problem.

“The study has shown that the great majority of assessments are consistent and therefore valid to aid in decision-making. These results are encouraging as they suggest that these protocols may be useful when facing the worrying forecasts of increasing biological invasions and their damages,” 

explains Rubén.

On the other hand, the researchers have observed that discrepancies across assessments might be due to multiple factors, such as the type of impact asked or the linguistic formulation used in the protocols.

The results suggest that there is room for improvement in assessments, but it will require more funding for research, and more multidisciplinary collaborations between ecologists and linguists to develop less ambiguous protocols.

As always, the most effective measure against biological invasions turns out to be prevention.

However, given the incapacity to control every voluntary and involuntary introduction, other tools such as impact assessments are essential to reduce as far as possible the damage caused by these species on human welfare and environment. Its continuous improvement and evaluation, such as the one made in this study, are decisive.

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Research article:

Bernardo-Madrid R, González-Moreno P, Gallardo B, Bacher S, Vilà M (2022) Consistency in impact assessments of invasive species is generally high and depends on protocols and impact types. In: Giannetto D, Piria M, Tarkan AS, Zięba G (Eds) Recent advancements in the risk screening of freshwater and terrestrial non-native species. NeoBiota 76: 163-190. https://doi.org/10.3897/neobiota.76.83028

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Genetically-enhanced biocontrols can help fight large invasive mammals

Genetic biocontrols could rapidly eradicate animals like rats, mice and rabbits. Others – like cats and foxes, would however take a lot longer.

But gene drives are not a one-size-fits-all solution

Invasive alien mammals can have catastrophic impacts on native flora and fauna, causing species extinctions and driving profound environmental change. Classical control methods such as poison baiting, trapping, or hunting are currently not feasible on a large scale, which is why researchers are looking for alternatives.

CRISPR-based genome engineering is often seen as a “silver bullet” for pest control. Despite the increasing interest in the development of this technology for invasive mammals like mice, rats, rabbits, feral cats, and foxes, studies have so far only focused on mice.

Scientists have been pondering whether genome editing technologies could help eradicate larger mammals, and if so, how long it would take.

Rabbit. Photo by Mark Philpott licensed under CC BY-NC 2.0.

In order to address these questions, a team of researchers from the University of Adelaide developed a mathematical model able to simulate the impact of gene drives on mammal populations at a landscape scale. Published in the open-access NeoBiota journal, their study is the first to estimate the time it would take to eradicate long-lived alien mammals.

Using CRISPR-Cas9 technology, the simulated gene drive relies on “molecular scissors” inserted into the Y-chromosome that target and slice up the X-chromosome at the right time during meiosis, so that only Y-chromosome carrying sperms are functional and can successfully fertilize the egg. In this way, the drive carrying males should only produce sons that also carry the molecular scissors on their Y-chromosome. Over multiple generations, females will become rarer and produce fewer offspring; as a result, the population size will fall.

Red fox. Photo by Rylee Isitt licensed under CC BY-SA 2.0.

This “X-shredder” drive has been successfully developed and demonstrated to suppress cage populations of malaria-carrying mosquitos, but has not yet been developed in mammals. The model shows that the X-shredder drive could potentially achieve landscape-scale eradication of mice, rats, rabbits, feral cats, and red foxes, but the probability of success and the time it would take to eradicate them vary greatly.

The researchers investigated the ability of the X-shredder drive to eradicate a population of 200,000 individuals of each species. “CRISPR-based gene drives offer novel solutions for controlling invasive alien species, which could ultimately extend eradication efforts to continental scales,” they concluded.

The method could be effective in small-sized pests, such as rodents and rabbits. The expected time to eradication is 18 years for mice, 19 years for rats, and 48 years for rabbits, with 90% population suppression achieved in around half those times.

However, the results suggest that gene drives are not a one-size-fits-all solution: they might not be so useful in larger species like cats and foxes.

“The probability of eradicating feral cats with gene drives is identical to flipping a coin, 50/50; and provided that the coin lands on the right side, it would take about 140 years to get rid of them,” says Dr. Aysegul Birand, part of the research team. “The probability of eradication is higher for foxes, but the wait is even longer.”

Original source: 

Birand A, Cassey P, Ross JV, Thomas PQ, Prowse TAA (2022) Scalability of genetic biocontrols for eradicating invasive alien mammals. NeoBiota 74: 93-103. https://doi.org/10.3897/neobiota.74.82394

Can amateurs combat the threat of alien species? Tracking introduced species in the world of citizen science

How citizen scientists documented the spread of an alien mantis across Australia

Guest blog post by Matthew Connors

From the infamous cane toad to the notorious spotted lanternfly, we all know the drastic effects that introduced species can have on both ecosystems and agriculture.

In today’s interconnected world, these alien species are being moved around the globe more frequently than ever before.  Hitchhikers and stowaways on ships, planes, and other vehicles can cause irreversible and catastrophic damage to fragile native ecosystems and to us humans, and tens of billions of dollars are spent every year trying to control these invaders.

Spotted lanternfly. Photo by peterlcoffey licensed under CC BY-NC-SA 2.0.

But one of the greatest problems for researchers and government bodies trying to combat these threats is that it can be incredibly difficult to monitor the invaders even when we know they’re here.

So how on earth is anyone supposed to detect when a new species has invaded?  Many of these organisms are small, inconspicuous, and difficult to identify, and by the time they’ve been spotted it’s often already too late to act.

What if there was a way to quickly and easily find invasive organisms all over the world?  Enter the world of Citizen Science, where anybody and everybody can produce important scientific data without even leaving their backyard.  Just by taking a photograph of an organism and uploading it to a citizen science platform like iNaturalist or QuestaGame, amateurs and enthusiasts can provide scientists with invaluable records from across the globe.

A screenshot from the iNaturalist homepage, captured on July 7, 2022.

Back in 2015, when amateur naturalist Adam Edmonds spotted an unusual praying mantis in his garden, he took a photo and posted it to the Australian citizen science platform BowerBird.  When even the local experts didn’t recognise it, a specimen was sent off to mantis specialist Graham Milledge.  He confirmed that it was a newly introduced species – the South African Mantis (Miomantis caffra).

Miomantis caffra, an adult female from Victoria, Australia. Photo by Adam Edmonds

Since then, this alien mantis has spread across Australia from Sydney to Perth.  And every step of the way, citizen scientists have been there to document its spread.

Last month, all of these citizen science records were compiled by entomologist Matthew Connors of James Cook University (Queensland, Australia) into the first comprehensive report of the mantis’s presence in Australia.  Understanding where the species has spread and what impacts it has had on native species is crucial to managing and controlling it.

The introduced South African Mantis (Miomantis caffra) preys on a native Harlequin Bug (Dindymus versicolor) in Geelong, Australia.  Photo by Kelly Clitheroe

The research found that the South African Mantis has spread through suburban habitats in three Australian states (Victoria, New South Wales, and Western Australia) and one offshore territory (Norfolk Island).  It probably arrived in these regions as egg cases attached to plants and equipment, and it can now be found in high numbers, especially during late summer and early autumn.  Despite this, it appears to be highly localised and has only been recorded in suburbia, and furthermore there has not been any noticeable impact on native species.

Miomantis caffra, egg case (ootheca) from Victoria, Australia. Photo by Ken Walker

None of this research would have been possible without citizen scientists – the dedicated community of enthusiasts and amateurs who share their finds with researchers online.  Photographs from citizen science platforms and social media sites have been instrumental in showing just how far the South African Mantis has spread.  In fact, more than 90% of the records of the species come from citizen scientists, and without them we would barely know anything.

These days, more and more researchers are realising just how useful citizen science can be.  As well as tracking introduced species, citizen scientists have rediscovered rare creatures, documented never-before-seen behaviours, and even discovered completely new species.

Miomantis caffra, an adult female from Victoria, Australia. Photo by Matthew Connors

This latest research, published in the Journal of Orthoptera Research, is among a handful of recent studies that have gone a step further though – instead of just being a source of data, the citizen scientists were invited to take part in the entire research process, from data collection all the way through to publishing.  After all, they did all of the fieldwork!

Research like this is proof that anyone can be a citizen scientist in today’s day and age – so what are you waiting for?

Research article: Connors MG, Chen H, Li H, Edmonds A, Smith KA, Gell C, Clitheroe K, Miller IM, Walker KL, Nunn JS, Nguyen L, Quinane LN, Andreoli CM, Galea JA, Quan B, Sandiford K, Wallis B, Anderson ML, Canziani EV, Craven J, Hakim RRC, Lowther R, Maneylaws C, Menz BA, Newman J, Perkins HD, Smith AR, Webber VH, Wishart D (2022) Citizen scientists track a charismatic carnivore: Mapping the spread and impact of the South African Mantis (Miomantidae, Miomantis caffra) in Australia. Journal of Orthoptera Research 31(1): 69-82. https://doi.org/10.3897/jor.31.79332

Now accepting contributions on the impact of alien insects in the Alpine ecosystem

Alpine Entomology invites researchers to submit their work assessing the possible impacts of invasive insects on mountain areas.

Invasive insects can be vectors of diseases, cause damage to agriculture and forestry, and threaten native biodiversity. Recognising this dramatic impact, the open-access journal Alpine Entomology, published by Pensoft on behalf of the Swiss Entomological Society, opened a dedicated topical collection that is already accepting submissions.

Impacts of alien insects in the Alpine ecosystem invites scientists working on invasive species and plant-insect interactions in Alpine regions to openly publish their research articles, review articles, and short communications on, among others, trends or changes in biogeography of emblematic species, shifts in current distributions, or niche replacement.

The new article collection will be edited by Oliver Martin of ETH Zürich, subject editor and editorial board member at Alpine Entomology, Stève Breitenmoser, and Dominique Mazzi.

“Recent years have seen a worldwide increase in invasions by alien species, especially plants and insects, mostly due to trade and climate change,” they explain, noting that although numerous studies exist on the topic, few of them focus on the Alpine areas.

“With this collection we hope to generate exciting discussions and exchange within the scientific community interested in this very particular and sensitive ecosystem,” the editors say, inviting authors to submit their manuscripts assessing the possible impacts of invasive insects on mountain areas.

The collection will remain open for submissions for the next two years. In the meantime, the accepted manuscripts will be published on a rolling basis, as soon as they are ready for publication.

Alpine Entomology is currently accepting submissions to one other topical collection, Trends in arthropods of alpine aquatic ecosystems.

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Invasive alien species? Isn’t there an app for that?

Scientists review 41 invasive species reporting apps and provide recommendations for future development.

Invasive alien species (IAS) are a leading contributor to biodiversity loss, and they cause annual economic damage in the order of hundreds of billions of US dollars in each of many countries around the world. Smartphone apps are one relatively new tool that could help monitor, predict, and ideally prevent their spread. But are they living up to their full potential?

A team of researchers from the University of Montana, the Flathead Lake Biological Station and the University of Georgia River Basin Center tried to answer that in a recent research paper in the open access, peer-reviewed journal NeoBiota. Going through nearly 500 peer-reviewed articles, they identified the key features of the perfect IAS reporting app and then rated all known English-language IAS reporting apps available to North America users against this ideal.

Smartphone apps have the potential to be powerful reporting tools. Citizen scientists the world around have made major contributions to the reporting of biodiversity using apps like iNaturalist and eBird. But apps for reporting invasive species never reached that level of popularity; Howard and his team investigated why.

Smartphone apps like the soon-to-be-released new EDDmapS platform are promising tools for monitoring, predicting, and reducing the spread of invasive species. However, the same explosion of reports has not been realized as that which has been experienced by biodiversity-wide platforms. Howard et al. investigate why there has not been the same boom in use observed for these invasive species-specific apps. Image by Leif Howard and Charles van Rees

User uptake and retention are just as important as collecting data. Howard and colleagues found that apps tend to do a good job with one of these, and rarely with both. In their paper, they emphasize that making apps user-friendly and fun to use, involving games and useful functions like species identification and social media plug-ins is a major missing piece among current apps.

“The greatest advancement in IAS early detection would likely result from app gamification,” they write.

Another feature they would like to see more of is artificial intelligence or machine learning for photo identification, which they believe would greatly enhance species identification and might increase public participation.

The authors also make suggestions for future innovations that could make IAS reporting apps even more effective. Their biggest suggestion is coordination. 

“Currently, most invasive species apps are developed by many separate organizations, leading to duplicated effort and inconsistent implementation”, they say. “The valuable data collected by these apps is also sent to different databases, making it harder for scientists to combine them for useful research.”

A more efficient way to implement these technologies might be providing open-source code and app templates, with which local organizations can make regional apps that contribute data to centralized databases. 

Overall, this research shows how with broader participation, more complete and informative reporting forms, and more consistent and structured data management, IAS reporting apps could make much larger contributions to invasive species management worldwide. This, in turn, could save local, regional, and national economies hundreds of millions or billions of dollars annually, while protecting valuable ecological and agricultural systems for future generations.

Research article:

Howard L, van Rees C, Dahquist Z, Luikart G, Hand B (2022) A review of invasive species reporting apps for citizen science and opportunities for innovation. NeoBiota 71: 165-188. https://doi.org/10.3897/neobiota.71.79597

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Study ranks potentially harmful invasive species in Ghana

Scientists ranked the 110 arthropod and 64 pathogenic species posing the greatest potential threat to the country if established.

A CABI-led study has conducted a comprehensive survey of nearly 200 potentially harmful alien plant species that could have a detrimental impact upon agriculture, forestry and biodiversity in Ghana once they enter the country.

Invasive Alien Species (IAS) continue to shape the global landscape through their effects on biological diversity and agricultural productivity. The effects are particularly pronounced in Sub-Saharan Africa, which has seen the arrival of many IAS in recent years. This has been attributed to porous borders, weak cross border biosecurity, and inadequate capacity to limit or stop invasions.

A farmer shows cassava root affected by cassava brown streak virus alongside a healthy root in a country where the disease is present – one of the 64 pathogens assessed by the scientists. Credit: CABI

The research, the findings of which are published in the journal NeoBiota, ranks 110 arthropod and 64 pathogenic species that pose the greatest threat but are not yet officially present in the country. However, they could arrive as ‘stowaways’ in cargo from other countries around the world, the scientists believe.

Dr Marc Kenis, Head Risk Analysis and Invasion Ecology at CABI, led on the horizon scanning exercise supported by colleagues from a range of institutions including Ghana’s Plant Protection and Regulatory Services Directorate (PPRSD).

Among the top arthropods prioritised by Dr Kenis and his team were the pink hibiscus mealybug (Maconellicoccus hirsutus Green) and melon thrips (Thrips palmi Karny) while the top pathogens highlighted include cassava brown streak virus and Maize lethal necrosis disease.

Cassava in Ghana, for example, is a main staple crop and contributes about 22% and 30% to the Agricultural Gross Domestic Product (AGDP) and daily calories intake respectively. The crop, however, can be at risk from cassava brown streak virus which can reduce yields by up to 70%.

Maize lethal necrosis disease, on the other hand for instance, can be a major disruptor of maize crops in Ghana where maize accounts for more than 50% of the country’s total cereal production. The disease can cause losses of between 50-90% depending on the variety of maize and the growing conditions of the year.

The scientists also found other species recorded in Africa that included 19 arthropod and 46 pathogenic species which were already recorded in the neighbouring countries of Burkina Faso, Côte d’Ivoire, and Togo.

Dr Kenis, who is based at CABI’s centre in Switzerland, said, “The ultimate objective of this research was to enable prioritization of actions including pest risk analysis, prevention, surveillance and contingency plans. Prioritisation was carried out using an adapted version of horizon scanning and consensus methods developed for ranking IAS worldwide.

“We have demonstrated that through horizon scanning, a country can identify potential invasive plant pests, both invertebrates and pathogens, and use the information to determine the risk associated with each.

“This will enable the country to invest the limited resources in priority actions such as preventing arrival and establishment of IAS, Pest Risk Analysis (PRA), surveillance and developing contingency plans.

“This study can serve as a model for future projects on plant pests’ prioritisation in Africa and elsewhere. It would be applicable for assessing the risk of invasive plant pests in any country or region, e.g. trade blocks, with minor modifications of the method, particularly in the mini-PRA protocol used to score species.”

The full lists of arthropod and pathogenic species surveyed can be found within the full paper which can be read online.

Mr Prudence Attipoe, Deputy Director Head Plant Quarantine Division, PPRSD, said, “The horizon scanning exercise for Ghana would give the PPRSD an insight into invasive pests which could possibly enter the Nation. The tool is timely and appropriate for conducting PRA for planning, training and future preparedness. The success of this exercise would pre-empt the introduction of these invasive pests into the country in order to protect Ghana’s agriculture, forestry and also cause staff of PPRSD to be more vigilant at the borders for these pests.”

Research paper:

Kenis M, Agboyi LK, Adu-Acheampong R, Ansong M, Arthur S, Attipoe PT, Baba A-SM, Beseh P, Clottey VA, Combey R, Dzomeku I, Eddy-Doh MA, Fening KO, Frimpong-Anin K, Hevi W, Lekete-Lawson E, Nboyine JA, Ohene-Mensah G, Oppong-Mensah B, Nuamah HSA, van der Puije G, Mulema J (2022) Horizon scanning for prioritising invasive alien species with potential to threaten agriculture and biodiversity in Ghana. NeoBiota 71: 129 148. https://doi.org/10.3897/neobiota.71.72577

How to get people interested in invasive species?

While blacklists are an effective tool for preventing and managing new biological invasions, they don’t always raise public awareness of invasive alien species, a new study published in the open-access journal NeoBiota found. Important policy-making initiatives do not necessarily raise public awareness about biological invasions, and efforts should be more focused on supporting policy-making with well-planned communication campaigns, the research concludes.

Catchy news and viral videos work best to attract public attention to invasive alien species

Blacklists are one of the most common policy measures to limit biological invasions. They identify small groups of highly impactful invasive alien species: species introduced outside their native range that threaten biodiversity. By doing so, they inform key decision-makers, who then impose limitations or bans on their trade and introduction, or set requirements about specific actions to manage already established populations.

While they have been found to be effective at preventing and managing new biological invasions, we don’t know if blacklists actually raise public awareness of invasive alien species. In principle, they could do so, as they might attain a certain echo in the media and provide the general public with notorious examples of invasive alien species.

Coypu. Photo by Aurelio Perrone

In 2016, the European Union published the List of Invasive Alien Species of Union concern, which contains species that are banned from import, trade, and release in Europe. It had a certain echo in the media, and having come at a time where Internet searches are so pervasive that they can be used to measure public attention,  the Union List made a good case study for exploring blacklist impact on public awareness.

A research study, coordinated by Jacopo Cerri from the University of Primorska, Slovenia, and Sandro Bertolino from the University of Turin, Italy, explored if the publication of the Union List increased visits of the  Italian Wikipedia pages about invasive alien mammals, many of which were included in the list. Wikipedia is the largest online encyclopedia and a major source of information for motivated Internet users who go beyond search engines such as Google. As a comparison, the researchers used visits to Wikipedia pages about native mammals in Italy, and adopted a causal impact analysis to quantify differences.

The study found no effect of the publication of the Union lists over visits to Italian Wikipedia pages of invasive alien mammals, compared to pages about native mammals. After 2016, there were single peaks of visits to pages of some of the species, probably caused by viral videos and news about large-scale control initiatives or mass escapes from captivity. In one instance, peaks in visits aligned with news about the coypu – at the time, several national media outlets ran stories addressing the concerns of public administrations regarding the rodent’s impact on the stability of river banks. Similarly, a peak observed between late 2018 and February 2019 was likely caused by news about the release of 4,000 minks from a fur factory in Northern Italy, which attracted considerable attention in the national and regional media.

These attention peaks, however, did not last in time and don’t reflect a systematic change in public awareness about invasive alien species.

“Overall, our findings indicate that blacklists, despite having the potential to raise public awareness towards biological invasions, might fail to do so in practice,” the researchers conclude.

“Agencies who want to achieve this goal should rather develop tailored communication campaigns, or leverage on sensational news published in the media.”
 

Research article:

Cerri J, Carnevali L, Monaco A, Genovesi P, Bertolino S (2022) Blacklists do not necessarily make people curious about invasive alien species. A case study with Bayesian structural time series and Wikipedia searches about invasive mammals in Italy. NeoBiota 71: 113-128. https://doi.org/10.3897/neobiota.71.69422

NeoBiota invites risk analysis studies in a new Special Issue on advancements in the screening of freshwater and terrestrial non-native species

The “Recent advancements in the risk screening of freshwater and terrestrial non-native species” Special Issue in the open-access, peer-reviewed scholarly journal NeoBiota is now open for submissions. The deadline for submission is 30 April 2022, with the issue scheduled for publication in August 2022.

The “Recent advancements in the risk screening of freshwater and terrestrial non-native species” Special Issue in the open-access, peer-reviewed scholarly journal NeoBiota is now open for submissions.

The issue is managed by the international team of guest editors of Dr Daniela Giannetto (Mugla Sitki Kocman University, Turkey), Prof. Marina Piria (University of Zagreb, Croatia), Prof. Ali Serhan Tarkan (Mugla Sitki Kocman University, Turkey) and Dr Grzegorz Zięba (University of Lodz, Poland).

Update: The deadline for submission has been extended to 30 April 2022, with the issue expected to be published in August 2022. 

The new special issue is expected to collate prominent contributors from the field of invasive ecology, thereby addressing existing gaps in the knowledge about both freshwater and terrestrial non-native species and their management.

The editors note that despite the current efforts and measures to monitor and tackle the spread of non-native species, and especially those posing imminent threat to local biodiversity and ecosystems, further expansion of such populations has increasingly been recorded in recent years. Of special concern are developing countries, where legislation for controlling non-native species is still lacking.

A major problem is that – as of today – we are still missing on risk screening studies needed to provide evidence for the invasiveness potential of many non-native species across several taxonomic groups, which would then be used to support specific conservation efforts. Unfortunately, this is particularly true for species inhabiting the world’s biodiversity hotspots, point out the editors.

Risk-based identification of non-native species is an essential process to inform policy and actions for conservation and management of biodiversity. Previously published papers on risk screening of aquatic non-native species, and especially those using the most widely-employed ‘-ISK’ decision-support toolkits, have attracted mounting interest from the wider scientific community.

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Visit NeoBiota’s journal website at: https://neobiota.pensoft.net/ 

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What is the Asian hornet invasion going to cost Europe?

Since its accidental introduction in 2003 in France, the yellow-legged Asian hornet Vespa velutina nigrithorax is rapidly spreading through Europe. In a new paper, published in the open-access journal Neobiota, French scientists try to estimate the costs of the invasion regarding the potential damage to apiculture and pollination services.

Since its accidental introduction in 2003 in France, the yellow-legged Asian hornet (Vespa velutina nigrithorax) is rapidly spreading through Europe. Both experts and citizen scientists keep on identifying the new invader spreading all over the Old Continent in the last decades. 

In a recent study, French scientists led by Prof. Franck Courchamp at the Université Paris-Saclay and the CNRS, tried to evaluate the first estimated control costs for this invasion. Supported by the INVACOST project, their findings are published in the open-access journal Neobiota.

Since its invasion to France in 2004 when it was accidentally introduced from China, the Asian hornet has been spreading rapidly, colonising most of France at an approximate rate of 60-80 km per year, and also invading other European countries: Spain in 2010, Portugal and Belgium in 2011, Italy in 2012, Germany in 2014 and the UK in 2016. In the recent paper, published in the open-access journal Evolutionary Systematics, Dr. Martin Hussemann from CeNaK, University of Hamburg has recorded the northernmost capture of the Asian hornet in Hamburg in September 2019.

These data show that the Asian hornet is spreading all around Europe faster and faster with every year, even in climatically less favourable regions. The rapid invasion of the species is not necessarily caused by human-mediated dispersal, the species can rapidly spread on its own, but nevertheless, it is not uncommon.

Within its native and invasive range, V. velutina nigrithorax actively preys on honeybees, thus, causing harm to apiculture. Due to its active praying on wild insects, the Asian hornet also has a negative impact on ecosystems in general and contributes to the global decline of pollination services and honey production. Furthermore, by nesting in urban areas, the Asian hornet, which is well known for its aggressive behaviour, is a potential threat to human activities.

Currently, the control of the invasion is mainly undertaken by nest destruction and bait trapping, but none of these methods is sufficient enough to achieve complete eradication.

To proceed with the further control of the invasion, there is the need to evaluate economic costs. Those costs are divided into 3 main categories: (1) prevention of the invasion, (2) fighting the invasion and (3) damage caused by the invasion.

The cost of fighting the invasion of the Asian hornet is the cost of nest destruction. To identify those costs, the research team has studied information about the companies providing the services in the nest destruction, extrapolated the cost of nest destruction spatially and modelled the potential distribution of the invasive.


Estimated yearly cost of nest destruction if climatically suitable areas are fully invaded. Grey bars represent countries invasion hasn’t reached yet.
Credit: Prof. Franck Courchamp
License: CC-BY 4.0

As the calculations show, at the moment, the estimated yearly costs for eradication would be €11.9M for France, €9.0M for Italy and €8.6M for the United Kingdom.

“In 2006, only two years after the hornet was first observed in France, three departments were already invaded and the cost of nest destruction was estimated at €408k. Since then, the estimated yearly costs have been increasing by ~€450k each year, as the hornet keeps spreading and invades new departments. Overall, we estimated €23M as the cost of nest destruction between 2006 and 2015. If this temporal trend can be extrapolated for the next few years (i.e. if the hornet keeps spreading at a similar rate), we expect the yearly cost of nest destruction to reach an estimated value of €11.9M (given all suitable areas are invaded) in just 12 years,”

shares Prof. Franck Courchamp.

In Japan and South Korea, where the species has already been observed, the total yearly cost of nest destruction is estimated at €19.5M and €11.9M respectively.

So far, nests eradication is the most effective way to fight the invasion, though, it is not sufficient enough. As a result, so far, only 30-40% of the detected nests are destroyed each year in France. Moreover, rather than the result of a controlled strategy, those destroyed nests are only the ones that have been determined of particular potential harm to human or beekeeping activities. The researchers point out that this is not enough.


Estimated yearly cost of nest destruction in France since the start of the invasion given the yearly invasive range.
Credit: Prof. Franck Courchamp
License: CC-BY 4.0

In conclusion, the scientists call for more active measures and research, related to the invasion of V. velutina nigrithorax. Provided that other countries, including the USA, Australia, Turkey and Argentina appear to be climatically suitable for the species, they are also in danger (e.g., €26.9M for the USA).

The current study presents only the first estimates of the economic costs resulting from the Asian hornet, but definitely more actions need to be taken in order to handle harmful invasive species – one of the greatest threats to biodiversity and ecosystem functioning.

Consensus climate suitability of the yellow-legged hornet predicted from species distribution modelling.
Credit: Prof. Franck Courchamp
License: CC-BY 4.0

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Original source:

Barbet-Massin M, Salles J-M, Courchamp F (2020) The economic cost of control of the invasive yellow-legged Asian hornet. NeoBiota 55: 11-25. https://doi.org/10.3897/neobiota.55.38550

New improvements to how impacts of non-native species are assessed recommended

A farmer sets a pheromone trap to fight tomato leaf miner. Photo by CABI.

The Centre for Agriculture and Bioscience International (CABI) has led an international team of non-native species (NNS) specialists who have compiled a list of recommendations to improve the way in which the impact of a range of invasive pests – such as the tomato leaf miner Tuta absoluta – are assessed, potentially helping towards ensuring greater global food security.

Lead authors Dr Pablo González-Moreno and Dr Marc Kenis, Senior Researchers at CABI are two of 89 NNS experts from around the world who have collaborated on the paper, published in NeoBiota, that calls for ‘more robust and user-friendly’ impact assessment protocols to predict the impacts of new or likely invaders as well as to assess the actual impact of established species.

The manuscript is the outcome of an enormous collective effort using 11 different protocols to assess the potential impact of 57 NNS to Europe yielding a total of 2614 separate assessments. This unique dataset has allowed the authors to identify which are the main factors increasing the robustness of protocols and provide recommendations on how the robustness and applicability of protocols could be enhanced for assessing NNS impacts.

As reported in the study, entitled ‘Consistency of impact assessment protocols for Non-Native Species’, Dr González-Moreno and fellow scientists – from 80 institutions including the UK-based Centre for Ecology & Hydrology (CEH), University of Milan, University of Bern and Queens University Belfast – argue that ‘assessment of the realised or potential impacts of NNS is particularly important for the prioritization of management actions.’

Millions of the world’s most vulnerable people face problems with invasive weeds, insects and plant diseases, which are out of control and have a major impact on global prosperity, communities and the environment. Developing countries are disproportionately affected.

The global cost of the world’s 1.2 million invasive species is estimated at $1.4 trillion per year – close to 5 percent of global gross domestic product. In East Africa, five major invasive species alone cause $1 billion in economic losses to smallholder farmers each year.

The scientists believe that, currently, the large variety of metrics adopted to measure the impacts of invasive species undermines direct comparison of impacts across species, groups of taxa, localities or regions. They go on to argue that in general we have ‘little understanding of the patterns in consistency of impact scores across assessors and protocols, and more importantly, which factors contribute to high levels of consistency.’

Dr González-Moreno said,

“There is an increasing demand for robust and user-friendly impact assessment protocols to be used by professionals with different levels of expertise and knowledge.
Robust NNS impact protocols should ideally result in accurate and consistent impact scores for a species even if applied by different assessors, as long as they have the adequate expertise in the assessed species and context.
Several key factors should be taken into account when selecting or designing an NNS risk assessment protocol, such as the aim, the scope, the consistency and the accuracy of the outcomes, and the resources available to perform the assessment – for example time or information available.”

In compiling a list of recommendations for improved NNS impact protocols, Dr González-Moreno and the team of researchers used 11 different protocols to assess the potential impact of 57 species not native to Europe and belonging to a very large array of taxonomic groups (plants, animals, pathogens) from terrestrial to freshwater and marine environments.

They agree that using a ‘5-level scoring, maximum aggregation method and the moderation of expertise requirements’ offers a good compromise to reducing inconsistencies in research findings without losing discriminatory power or usability.

Dr González-Moreno added, “In general, we also advise protocol developers to perform sensibility tests of consistency before final release or adoption. This is crucial as if a protocol yields inconsistent outcomes when used by different assessors, then it is likely that decisions taken based on the results could be variable and disproportionate to the actual impacts.”

Original source:

González-Moreno P, Lazzaro L, Vilà M, Preda C, Adriaens T, Bacher S, Brundu G, Copp GH, Essl F, García-Berthou E, Katsanevakis S, Moen TL, Lucy FE, Nentwig W, Roy HE, Srėbalienė G, Talgø V, Vanderhoeven S, Andjelković A, Arbačiauskas K, Auger-Rozenberg M-A, Bae M-J, Bariche M, Boets P, Boieiro M, Borges PA, Canning-Clode J, Cardigos F, Chartosia N, Cottier-Cook EJ, Crocetta F, D’hondt B, Foggi B, Follak S, Gallardo B, Gammelmo Ø, Giakoumi S, Giuliani C, Guillaume F, Jelaska LS, Jeschke JM, Jover M, Juárez-Escario A, Kalogirou S, Kočić A, Kytinou E, Laverty C, Lozano V, Maceda-Veiga A, Marchante E, Marchante H, Martinou AF, Meyer S, Michin D, Montero-Castaño A, Morais MC, Morales-Rodriguez C, Muhthassim N, Nagy ZA, Ogris N, Onen H, Pergl J, Puntila R, Rabitsch W, Ramburn TT, Rego C, Reichenbach F, Romeralo C, Saul W-C, Schrader G, Sheehan R, Simonović P, Skolka M, Soares AO, Sundheim L, Tarkan AS, Tomov R, Tricarico E, Tsiamis K, Uludağ A, van Valkenburg J, Verreycken H, Vettraino AM, Vilar L, Wiig Ø, Witzell J, Zanetta A, Kenis M (2019) Consistency of impact assessment protocols for non-native species. NeoBiota 44: 1-25. https://doi.org/10.3897/neobiota.44.31650

Additional information:

The paper is based upon work from the COST Action TD1209: ALIEN Challenge. COST (European Cooperation in Science and Technology) is a pan-European intergovernmental framework. The mission of COST is to enable scientific and technological developments leading to new concepts and products and thereby contribute to strengthening Europe’s research and innovation capacities.

Dr Pablo González-Moreno was supported by the CABI Development Fund (with contributions from ACIAR (Australia) and DFID (UK) and by Darwin plus, DPLUS074 ‘Improving biosecurity in the SAUKOTs through Pest Risk Assessments’.

 

Text originally published by CABI.