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.
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.”
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
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
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.
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
This happens more than you might think, with pet releases deemed responsible for 53% of invasive vertebrate species and one third of all aquatic invasive species. It has been shown that the more readily available a species is in the pet trade, the greater the risk of it being released, or escaping, into the wild.
Somewhat fascinatingly, this also puts the trade at the mercy of pop culture influences. 1970s animated series “Rascal the Raccoon” is commonly blamed for Japan’s invasive racoon population, and demand for Trachemys scripta pets is said to have boomed in the 1990s due to “Teenage Mutant Ninja Turtles.” Side note: the influence of movies highlighting the challenges of pet ownership, such as “Gremlins” or “Little Shop of Horrors”, warrants further study.
Hitchhikers
While invasion ecology has typically focused on these released species and the impacts that they cause, many species are sold with commensal organisms attached. These incidentally carried fauna are commonly known as “hitchhikers”.
Recent studies have found the protozoan Vorticella sp. and a species of bdelloid rotifer associated with two species of atyid shrimps, digenean larvae with the carnivorous snail Anentome helena, and an epibiont, Diceratocephala boschmai, on New Guinean ornamental Cherax crayfish.
Temnocephalid eggs located on thorax carapace (white arrow) of adult Cherax monticola. From Ložek F, Patoka J, Bláha M. 2021. Another hitchhiker exposed: Diceratocephala boschmai (Platyhelminthes: Temnocephalida) found associated with ornamental crayfish Cherax spp. Knowl. Manag. Aquat. Ecosyst., 422, 25.
A high-profile example emerged in 2021 when zebra mussels (Dreissena polymorpha) were detected in 21 US states on aquarium moss balls that had been imported from Ukraine, and subsequent searches revealed the species in 600 locations in Canada. Similar findings have since emerged from Europe. Having colonised both European and North American waters, the ease with which this Ponto-Caspian bivalve is being spread by the pet trade on both sides of the Atlantic is a major concern. Zebra mussels have been listed as one of the IUCN’s “100 of the Worst Invasive Species”, and their myriad ecological and economic impacts range from habitat alteration, to competition with native unionids, to disruption of food-web structure, to blocking industrial water intake pipes. They are also able to attach to boat hulls and other organisms, facilitating further spread.
The discovery
Zebra mussels, Dreissena polymorpha, found amongst ordered European pond snail, Viviparus viviparus
I remember the moment clearly. I had ordered seventy-five Viviparus viviparus – a common European pond snail species – for behavioural studies at GEOMAR Helmholtz Centre for Ocean Research Kiel where I was based for lab work in the group of Elizabeta Briski. After some stress over posting delays and an increasingly fraught relationship developing with the GEOMAR receptionist, the snails arrived. Over the next day, watching them go about their lives in our climate chamber in their new tanks became a favourite way to spend working breaks. With obvious dimorphism you could clearly tell males from females, which added to the developing snail soap operas. However, just before packing up to leave the lab, I noticed a huge lump on one snail. What on earth is that? Soon I noticed a second. I called Elizabeta with my suspicions, which she confirmed the next day. Photos were taken, measurements made, and our go-to ecological geneticist Reid Brennan was begged to work his DNA sequencing magic. Before long, it was all confirmed: we had zebra mussels.
Potential implications
The biggest takeaway message here is that even native species in the pet trade can facilitate the spread of non-native hitchhikers. In a parallel universe, those snails did not go to an invasion ecology lab but rather to someone keen to stock their garden pond. Escape from ponds is a major pathway for freshwater species introductions, and even if the impact of a native species escaping might be limited, its potential for the zoochorous dispersal of a non-native should not be ignored.
Zebra mussels, Dreissena polymorpha, found amongst ordered European pond snail, Viviparus viviparus.
Of course, questions surround the conditions under which the pond snails were held before selling. Were they stocked in zebra mussel infested outdoor ponds? Which other species are held in a similar way? How prevalent are these practices within the trade? One way of combating this risk of non-native species spread is via legislation. Calls have been made for white lists of low-risk species that can be sold in the trade in place of risky species, but in our study, the issue stems from the selling of a native species within its native range, which would surely be deemed low-risk.
We propose that should a white-list system be adopted, the potential for a “low-risk” species to transport invasive species must be accounted for. We also call for stricter biosecurity practices to be enforced, including regular checking and disinfecting of outdoor stock ponds where appropriate. Tools such as environmental DNA surveillance could be used to effectively detect the presence of targeted invasive species, as part of biosecurity “audits”. However, for the time being, a desperate, final line of defence is to raise awareness amongst consumers and for them to be wary of unwanted hitchhikers.
References:
Dickey JWE, Brennan RS, Chung SS, Jeschke JM, Steffen GT, Briski E (2023) More than we bargained for: Zebra mussels transported amongst European native freshwater snails. NeoBiota 10: 1–10. https://doi.org/10.3897/neobiota.83.97647
DeRoy EM, Scott R, Hussey NE, MacIsaac HJ (2020) Density dependence mediates the ecological impact of an invasive fish. Diversity and Distributions 26: 867–880. https://doi.org/10.1111/ddi.13063
Gippet JMW, Bertelsmeier C (2021) Invasiveness is linked to greater commercial success in the global pet trade. Proceedings of the National Academy of Science USA 118. https://doi.org/10.1073/pnas.2016337118
Lozek F, Patoka J, Bláha M (2021) Another hitchhiker exposed: Diceratocephala boschmai (Platyhelminthes: Temnocephalida) found associated with ornamental crayfish Cherax spp. Knowledge and Management of Aquatic Ecosystems 2020-Janua. https://doi.org/10.1051/kmae/2021023
Militz TA, Foale S (2017) The “Nemo Effect”: Perception and reality of Finding Nemo’s impact on marine aquarium fisheries. Fish and Fisheries 18: 596–606. https://doi.org/10.1111/faf.12202
Padilla DK, Williams SL (2004) Beyond ballast water: Aquarium and ornamental trades as sources of invasive species in aquatic ecosystems. Frontiers in Ecology and the Environment 2: 131–138. https://doi.org/10.1890/1540-9295(2004)002[0131:BBWAAO]2.0.CO;2
Patoka J, Patoková B (2021) Hitchhiking Exotic Clam: Dreissena polymorpha (Pallas, 1771) Transported via the Ornamental Plant Trade. Diversity 13: 1–5.
Patoka J, Magalhães ALB, Kouba A, Faulkes Z, Jerikho R, Vitule JRS (2018) Invasive aquatic pets: Failed policies increase risks of harmful invasions. Biodiversity and Conservation 27: 3037–3046. https://doi.org/10.1007/s10531-018-1581-3
Richardson MJ, Whoriskey FG, Roy LH (1995) Turbidity generation and biological impacts of an exotic fish Carassius auratus, introduced into shallow seasonally anoxic ponds. Journal of Fish Biology: 576–585.
Saul WC, Roy HE, Booy O, Carnevali L, Chen HJ, Genovesi P, Harrower CA, Hulme PE, Pagad S, Pergl J, Jeschke JM (2017) Assessing patterns in introduction pathways of alien species by linking major invasion data bases. Journal of Applied Ecology 54: 657–669. https://doi.org/10.1111/1365-2664.12819
Simberloff D (2006) Risk assessments, blacklists, and white lists for introduced species: Are predictions good enough to be useful? Agricultural and Resource Economics Review 35: 1–10. https://doi.org/10.1017/S1068280500010005
Stanicka A, Maciaszek R, Cichy A, Templin J, Świderek W, Żbikowska E, Labecka AM (2022) Unwanted ‘hitchhikers’ of ornamental snails: A case report of digeneans transported via the international pet trade. The European Zoological Journal 89: 601–607. https://doi.org/10.1080/24750263.2022.2065039
Zeng Y, Shakir KK, Yeo DCJ (2019) Competition between a native freshwater crab and an invasive crayfish in tropical Southeast Asia. Biological Invasions 21: 2653–2663. https://doi.org/10.1007/s10530-019-02009-6
A citizen science project in Italy had high school students monitor the activities of ambrosia beetles, catching them with traps made from recycled plastic bottles.
While invasive alien species (IAS) represent a growing threat to global biodiversity and ecosystems, public awareness of them hasn’t seen a significant increase. Many researchers believe informing people about IAS is an essential long-term investment to counter biological invasions; in particular, “learning by doing” is an extremely effective method for involving new audiences, such as students.
Map of the study area (the Veneto Region) indicating the high school locations.
About 500 Italian students aged 11-18 took part in a citizen science project that led to new geographical records of two alien species of ambrosia beetles considered to be quarantine pests by the European Union. Dr. Fernanda Colombari and Prof. Andrea Battisti of the University of Padova have described the results in a paper in the open-access journal NeoBiota.
The project involved schools located in urban areas in north-eastern Italy and aimed to connect environmental education and experiential outdoor learning through lectures, videos, reports, and large-scale surveillance of ambrosia beetles. The students used plastic bottles and hand sanitizer to trap ambrosia beetles in their school grounds. They then assessed their abundance, looking at the different species. Before and after the educational activities, their knowledge and awareness of IAS were tested using simple anonymous questionnaires.
Schematic representation of a plastic bottle trap filled with hand sanitizer as attractant
“Our study aimed to both educate students and collect scientific data at sites such as schools where surveillance for potentially invasive ambrosia beetles is not usually conducted, or where it is sometimes misunderstood,” Dr. Colombari and Prof. Battisti write in their paper.
Identifying the specimens collected by the students, the authors found that IAS amounted to 35% of total catches. Remarkably, two out of the four alien species caught, Cnestus mutilatus and Anisandrus maiche, were recorded for the first time in Europe thanks to this study.
Furthermore, questionnaire results showed that the students acquired greater knowledge and increased their awareness and interest in IAS by more than 50%. After the experiment, most of them were interested in learning more about the negative effects of the introduction of IAS and practices to limit their spread.
This study shows that citizen science can successfully involve school students, giving them an opportunity to contribute in an effective early detection of IAS, as most first records occur in cities or suburban areas. The results also point to the primary role of education, which is as a major driver of change in tackling sustainability challenges. Moreover, as students bring home the message and share it with their relatives, the process supports intergenerational learning and enlarges public collaboration.
A plastic bottle trap filled with hand sanitizer as attractant. Photo by Dr Fernanda Colombari
“People are often unaware of the role they have in the entire invasive process,” the researchers write in their study. Citizen science projects like this one are more than a reliable tool for collecting scientific data; they also help engage the public and spread awareness of biological invasions, eventually contributing to the creation of more efficient management strategies.
The monitoring programme in this study was conducted in the context of the European project HOMED (Holistic management of emerging forest pests and diseases), which has developed a full panel of scientific knowledge and practical solutions for the management of emerging native and non-native pests and pathogens threatening European forests. The main results of HOMED’s research are publically available in a special issue in the open-access scholarly journal NeoBiota.
Original source:
Colombari F, Battisti A (2023) Citizen science at school increases awareness of biological invasions and contributes to the detection of exotic ambrosia beetles. In: Jactel H, Orazio C, Robinet C, Douma JC, Santini A, Battisti A, Branco M, Seehausen L, Kenis M (Eds) Conceptual and technical innovations to better manage invasions of alien pests and pathogens in forests. NeoBiota 84: 211-229. https://doi.org/10.3897/neobiota.84.95177
Early detection of pest infestation is an important first step in the adoption of control measures that can be tailored to specific local conditions. Remote sensing technology can be a helpful tool, allowing the quick scanning of large areas, but it’s not universally applicable as sometimes items can be hard to detect. Unmanned aerial vehicles (UAVs), or drones, on the other hand, can help by getting closer to individual trees and detecting smaller atypical signals.
The pine processionary moth is an insect infesting trees in gardens and parks, threatening public health because of the hairs released by its larvae, which can cause a stinging or itching sensation. The pest is rapidly growing in numbers and conquering new territories, which makes it a species of concern.
In a new study, researchers tested different deep learning methods to detect the nests made by pine processionary moth larvae on pine and cedar trees. Drones flying over the trees took images, which were then analysed with the help of artificial intelligence (AI) to identify and localise the nests.
Drone images from Portugal.
The use of AI on drone images proved effective to detect pine processing moth nests on trees of different species and sizes, even under variable densities. The method can be successfully used in both forest and urban settings to help detect moth nests. That way, tree health managers can be informed about where the nests are and take appropriate measures to contain the damage and the public health risks.
“The study proved the advantage of using UAVs to document the presence of at least one nest per tree,” the researchers write in their study, which was published in a special issue of the journal NeoBiota dedicated to forest pests in Europe. “It therefore represents a substantial step forward in the integration of the UAV survey with ground observations in the monitoring of the colonies of an important forest defoliating insect in the Mediterranean area.”
image from the ground in daylightimage from the ground in infrared lightimage from drone
Furthermore, they suggest that the method can be extended to other pests.
“This technique can pave new avenues in the surveillance and management of emerging and non-native pests of trees, where early detection and early action should go together to achieve a satisfactory level of protection,” the study authors write in conclusion.
Research article:
Garcia A, Samalens J-C, Grillet A, Soares P, Branco M, van Halder I, Jactel H, Battisti A (2023) Testing early detection of pine processionary moth Thaumetopoea pityocampa nests using UAV-based methods. In: Jactel H, Orazio C, Robinet C, Douma JC, Santini A, Battisti A, Branco M, Seehausen L, Kenis M (Eds) Conceptual and technical innovations to better manage invasions of alien pests and pathogens in forests. NeoBiota 84: 267-279. https://doi.org/10.3897/neobiota.84.95692
A study published in the open access journal NeoBiota reveals that citizens and stakeholders are becoming more and more aware of the Asian yellow-legged hornet
Wasps and hornets have a remarkable capacity of surviving transportation and establishing invasive populations in new areas. In some cases, this can generate massive environmental and socio-economic impacts. Such is the case of the Asian yellow-legged hornet (Vespa velutina), which has been spreading throughout Europe and worldwide, threatening to seriously impact beekeeping.
However, research shows that such invasions do not go unnoticed. A team of researchers working on the Asian yellow-legged hornet in Italy (Dr Jacopo Cerri from the University of Primorska, Slovenia, and Dr Simone Lioy, Prof. Marco Porporato and Prof. Sandro Bertolino, from Turin University, Italy) discovered that citizen awareness about invasive hornets is increasing.
Asian yellow-legged hornet (Vespa velutina) attacking a colony of honey bees (Apis mellifera) in Italy. Photo by Prof. Marco Porporato
Moreover, they found that the relevant stakeholders – such as beekeepers – are aware of the hornet’s impacts. They consider the Asian yellow-legged hornet as one of the major causes of honey bee decline in Italy, comparing its effects to those of pesticides, and believing it causes more damage than diseases or other native insects.
To evaluate public awareness of this invasive hornet,the researchers adopted an innovative methodology, which they describe in a paper in the open-access journalNeoBiota. In addition to surveying beekeepers, the authors also analysed Internet searches, focusing on Google queries and visits to relevant Wikipedia pages.
Honey bee. Photo by Andy Murray, CC BY-SA 2.0, via Wikimedia Commons
The team found that beekeepers stayed up to date with information on the Asian yellow-legged hornet thanks to a wide range of different channels, such as the Internet, specialized magazines, and activities with other members of their community. Interestingly, they found that conventional media and mailing lists seemed to be of little contribution to knowledge on this species.
With high reproductive potential and no specialized predators, the Asian yellow-legged hornet predates intensively upon the western honey bee, which could decrease pollination, undermine honey production and inflict consequences for the overwinter survival of colonies. It also limits the foraging activity of honey bees by determining a “foraging paralysis”, a state in which honey bees do not leave the colony, fearing its predation. On top of that, as the species builds its nests mainly in or near urban areas, it poses a risk of stings to people, which in some cases could lead to fatalities.
An increased consciousness in citizens and stakeholders will hopefully lead to a higher number of ‘aware eyes’ able to spot invasive hornets in different environments, the researchers explain. Timely reporting of their presence would allow the speedy activation of more appropriate management measures, containing any possible damages before it’s too late.
Research article:
Cerri J, Lioy S, Porporato M, Bertolino S (2022) Combining surveys and on-line searching volumes to analyze public awareness about invasive alien species: a case study with the invasive Asian yellow-legged hornet (Vespa velutina) in Italy. NeoBiota 73: 177-192.https://doi.org/10.3897/neobiota.73.80359
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 NeoBiotais now open for submissions.
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.
In a new study, published in the peer-reviewed open-access scholarly journal Neobiota, scientists estimated the desire of Australians to own non-native and/or illegal alien pets and the major trends in this practice. In addition, the team suggests ways to improve biosecurity awareness in the country.
Juvenile green iguanas for sale at Repticon Trading Convention 2018 in Palm Springs, Florida Photo by Adam Toomes
Unsustainable trade of species is a major pathway for the introduction of invasive alien species at distant localities and at higher frequencies. It is also a major driver of over-exploitation of wild native populations. In a new study, published in the peer-reviewed open-access scholarly journal Neobiota, scientists estimated the desire of Australians to own non-native and/or illegal alien pets and the major trends in this practice. In addition, the team suggests ways to improve biosecurity awareness in the country.
Over the last two decades, Australia has been experiencing an increased amount of non-native incursions from species prominent in the international pet trade, such as rose-ringed parakeets, corn snakes and red-eared sliders. On many occasions, these animals are smuggled into the country only to escape or be released in the wild.
In general, the Australian regulations on international pet trade are highly stringent, in order to minimise biosecurity and conservation risks. Some highly-desirable species represent an ongoing conservation threat and biosecurity risk via the pet-release invasion pathway. However, lack of consistent surveillance of alien pets held, legally or otherwise, in Australia remains the main challenge. While there are species which are not allowed to be imported, they are legal for domestic trade within the country. Pet keepers have the capacity to legally or illegally acquire desired pets if they are not accessible through importation, and the number of such traders is unquantified.
Since keeping most of the alien pets in Australia is either illegal or not properly regulated, it is really difficult to quantify and assess the public demand for alien wildlife.
A juvenile ball python for sale at Repticon Trading Convention 2018 in Palm Springs, Florida Photo by Adam Toomes
“We obtained records of anonymous public enquiries to the Australian Commonwealth Department of Agriculture, Water and the Environment relating to the legality of importation of various alien taxa. We aimed to investigate whether species desired in Australia were biased towards being threatened by extinction, as indicated by broader research on pet demand or towards being invasive species elsewhere, which would indicate trade-related biosecurity risks”,
According to the research team’s analysis, pets desired by Australians are significantly biased towards threatened species, invasive species and species prominent in the U.S. pet trade.
“This novel finding is of great concern for biosecurity agencies because it suggests that a filtering process is occurring where illegally smuggled animals may already be “pre-selected” to have the characteristics that are correlated with invasive species,”
warns Mr. Adam Toomes.
However, the bias towards species already traded within the U.S. suggests that there is potential to use this as a means of predicting future Australian desire, as well as the acquisition of pets driven by desire. Future research from the Invasion Science & Wildlife Ecology Group at The University of Adelaide will investigate whether Australian seizures of illegal pets can be predicted using U.S. trade data.
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Original source:
Toomes A, Stringham OC, Mitchell L, Ross JV, Cassey P (2020) Australia’s wish list of exotic pets: biosecurity and conservation implications of desired alien and illegal pet species. NeoBiota 60: 43-59. https://doi.org/10.3897/neobiota.60.51431
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 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’.
