International tourism can facilitate the dispersal of exotic species. A new analysis of data from tourism accommodations and exotic organism detections in New Zealand, published in NeoBiota, shows that levels of detection significantly correlated to international and domestic tourist movement, even with population levels taken into account. There was no detectable difference between the risk from international and domestic tourists, indicating that tourism as an activity correlates with the introduction and spread of exotic species.
Tourists, albeit unwittingly, may help such unwanted organisms spread further and conquer new lands – they can carry them over in their luggage or on their clothes and shoes. In 2011, a study from New Zealand found that, for every gram of soil on the footwear of aircraft passengers arriving from abroad, there were 2.5 plant seeds, 41 roundworms, 0.004 insects and mites, and many microorganisms, such as fungi that could cause plant diseases. Moreover, these organisms were alive, and some of them were known to be biosecurity threats. Importantly, tourism can introduce risk in two directions, namely from the arrival of international travellers and also the return of residents from international travel.
An important question, then, is to what degree they play a role in the spread of exotic organisms. A study, carried out by Dr Andrew Robinson of the Centre of Excellence for Biosecurity Risk Analysis at the University of Melbourne and Mark McNeill of AgResearch New Zealand, looks to answer that question.
To do so, the researchers compared data on the interceptions of exotic organisms in New Zealand against accommodation data for international and domestic tourists, factoring for the country’s population distribution. The study, recently published in the open-access journal NeoBiota, covered the period between 2011 and 2017, and the exotic organisms that were detected included insects, spiders, mites, snails, plants, and roundworms.
Robinson and McNeill found a significant relationship between levels of incursion detection and tourism accommodation records: the number of nights spent in hotels significantly correlated to the detection of exotic pests for that period. Importantly, the study found no significant difference between the effect of international and domestic tourism, proving that even travel within the country can facilitate the spread of exotic species. A significant positive correlation was also found between the detection of exotic organisms and population numbers across different regions.
“The core take-home message is that within-country tourism movements are significantly correlated to the detection of exotic pests,” the researchers explained. That is, tourists and returning residents bring bugs in, and both are implicated at spreading them once they are in the country. They suggest that biosecurity authorities should continue allocating resources to the management of invasive species and pests that get carried around by tourists and their activities.
However, they also point to the biosecurity risk posed by other possible pathways for of exotic organisms, such as sea freight. A comparison between the different ways of introduction and dispersal would provide a better understanding of relative risk, they conclude.
Research article:
Robinson AP, McNeill MR (2022) Biosecurity and post-arrival pathways in New Zealand: relating alien organism detections to tourism indicators. NeoBiota 71: 51-69. https://doi.org/10.3897/neobiota.71.64618
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.
The success of Classical Biological Control in the Western Paleartic ecozone is rarely dependent on the released biological control agent, but more often on other factors, such as the target pest, its host plant, or the circumstances of the releases
A CABI-led study has revealed that the success of Classical Biological Control (CBC) in Europe, North Africa and the Middle East is only rarely dependent on the released biological control agent, but more often on other factors, such as the target pest, its host plant, or the circumstances of the releases.
The research – published in the journal NeoBiota– suggests that the overall success of biological control introductions of insect predators and parasitoids against herbivorous insects in the Western Paleartic ecozone is comparable to the success of CBC worldwide. However, over 100 years of CBC in this region, has resulted in no overall rise in success in the fight against insect pests – including those of crops such as citrus, olive, potato, mulberry and various other fruits.
An illustration of a case of biological control of the Comstock mealybug Pseudococcus comstocki with the parasitoid wasp Allotropa burrelli. Image by Lukas Seehausen
Lead author Dr Lukas Seehausen, together with colleagues from CABI Switzerland, the University of Lisbon and the University of Bordeaux, argue that a focus on life-history traits of the biological control agent to increase the chances of successful CBC is not fully justified and should be complemented with the consideration of traits regarding the pest and its host plant, as well as other aspects of CBC, such as climate and management – including ways in which CBC agents are released.
For example, if a CBC agent is released repeatedly against the same pest in different years and countries, the chances of successful establishment and control of the target increase. This is an indication for the importance of release strategies for the success of CBC programmes.
Dr Seehausen said, “What makes our study different from others is that we studied factors that may impact the outcome of CBC not independently of each other but using a holistic analysis, which reveals their relative importance within the complexity of CBC programmes.
“The results from this study should be understood as a first step to give the incentive for a holistic, rather than an independent consideration of factors affecting the success of CBC.”
By filtering data from the BIOCAT catalogue, the scientists found that 780 introductions of insects for biological control were undertaken in the Greater Western Palearctic ecozone between 1890 and 2010. This constituted 416 agent-target combinations.
The results showed that eight countries were responsible for more than two thirds (70.5%) of all introductions: Israel (16.3%), Italy (14.0%), Former USSR (10.1%), France (7.3%), Greece (7.1%), Spain (6.0%), Egypt (5.3%), and Cyprus (4.4%). Within these countries, the percentage of complete target control was very variable.
Overall, the study showed that while the success of agent establishment was 32%, the successful impact of single agents on their target was 18% and the success of complete control was 11%.
However, the success rates of agent establishment and target control were higher in CBC projects targeting pests of woody plants than pests of other types of plants.
A reason for this, the scientists say, might be that being perennial, trees provide a more stable and predictable environment when compared to herbaceous plants such as annual plants or crops.
In carrying out the research, Dr Seehausen and the team added 15 new explanatory variables including consideration of the biological control agent feeding strategy, host range and life-stage killed by the biological control agent.
Dr Seehausen explains, “We found that only a few CBC agent-related factors significantly influenced the success of CBC – suggesting that the reoccurring focus on agent-related traits is not justified.
“Our attention should be redirected to include lower trophic levels and other aspects of CBC – such as abiotic factors including climate and management.”
The scientists conclude by stressing that analysis of the entire BIOCAT catalogue, or an updated version including more factors, should lead to further insights and help to develop decision support tools to increase the success of CBC at all levels.
Original source:
Seehausen ML, Afonso C, Jactel H, Kenis M (2021) Classical biological control against insect pests in Europe, North Africa, and the Middle East: What influences its success? NeoBiota 65: 169-191. https://doi.org/10.3897/neobiota.65.66276
Common ragweed is an annual plant native to parts of the United States and southern Canada. It’s an invasive species that has spread to Europe. An important agricultural weed, this plant is particularly well-adapted to living at roadsides, and there are several theories why.
Its rapid expansion in Europe can’t be explained by its natural dispersal rate, which is limited to distances of around 1 meter. Rather, there are other factors in play, human-mediated, that support its invasion success – along roads, for example, it spreads mainly thanks to agricultural machineries, soil movements, roadside maintenance and road traffic.
Common ragweed. Photo: Uwe Starfinger
Studying common ragweed’s distribution patterns is important, because its allergenic pollen affects human health, mainly in southeast Central Europe, Italy and France. Finding out where it thrives, and why, can help with the management and control of its populations.
This is why scientists Andreas Lemke, Sascha Buchholz, Ingo Kowarik and Moritz von der Lippe of the Technical University of Berlin and Uwe Starfinger of the Julius Kühn Institute set out to explore the drivers of roadside invasions by common ragweed. Mapping 300 km of roadsides in a known ragweed hotspot in Germany’s state of Brandenburg, they recorded plant densities at roadsides along different types of road corridors and subject to different intensities of traffic over a period of five years. They then explored the effect of traffic density and habitat type, and their interactions, on the dynamics of these populations. Their research is published in the open-access, peer-reviewed journal NeoBiota.
Surprisingly, high-traffic road cells displayed a consistently high population growth rate even in shaded and less disturbed road sections – meaning that shading alone would not be enough to control ragweed invasions in these sections. Population growth proceeded even on roadsides with less suitable habitat conditions – but only along high-traffic roads, and declined with reduced traffic intensity. This indicates that seed dispersal by vehicles and by road maintenance can compensate, at least partly, for less favorable habitat conditions. Disturbed low-traffic road cells showed constantly high population growth, highlighting the importance of disturbance events in road corridors as a driver for common ragweed invasions.
These findings have practical implications for habitat and population management of ragweed invasions along road networks. Reducing the established roadside populations and their seed bank in critical parts of the road network, introducing an adjusted mowing regime and establishing a dense vegetation layer can locally weaken, suppress or eradicate roadside ragweed populations.
Original source:Lemke A, Buchholz S, Kowarik I, Starfinger U, von der Lippe M (2021) Interaction of traffic intensity and habitat features shape invasion dynamics of an invasive alien species (Ambrosia artemisiifolia) in a regional road network. NeoBiota 64: 55-175. https://doi.org/10.3897/neobiota.64.58775
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
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
The Belgian coastal dunes, a protected habitat of high conservation value, are getting severely impacted by one of its worst enemies amongst invasive species: the Oregon grape. To help mitigate the detrimental effect of this North American shrub invader, Belgian scientists carried out an experiment to assess the effectiveness of different management methods.
The Belgian coastal dunes, a protected habitat of high conservation value, are getting severely impacted by one of its worst enemies amongst invasive species: the Oregon grape. To help mitigate the detrimental effect of this North American shrub invader, Belgian scientists carried out an experiment to assess the effectiveness of different management methods.
The Atlantic coastal dunes form a dynamic and diverse ecosystem, home to a large number of native species, many of which are regionally threatened. Embryonic dunes, shifting white dunes, moss dunes, dune grasslands, and dune slacks are considered high conservation value sites, according to the interpretation manual of European habitats. However, the dunes are highly affected by external influences, and one of the most important threats to their biodiversity are invasive non-native plant species. These plants often colonised the dunes as garden escapes or spread from garden waste dumps or public plantings. Oregon grape is one of the worst invaders amongst them.
Oregon grape growing on sand dune (Belgium). Photo by Tim Adriaens.
In their study, published in the open-access journal NeoBiota, the scientists, led by Tim Adriaens and Sam Provoost of the Research Institute for Nature and Forest (INBO), focus on the management of the current populations of Oregon grape (Berberis aquifolium) in the Belgian coastal dunes, where the species has already managed to invade half of the 46 nature reserves and is starting to replace native vegetation. Such a negative effect on the biodiversity of the area requires practical management advice. Due to the high level of infestation of the dunes, the researchers recommend prompt eradication as the most appropriate management strategy. So far, however, it has been unclear which method would show the best effectiveness.
“Invasive shrub species exert an additional pressure on Belgian dune ecosystems, which are already highly fragmented by urbanisation. Oregon grape is one of the worst and should be tackled urgently before it gets out of control,” says Tim Adriaens.
Having compared four previously suggested treatments: manual uprooting, foliar herbicide application, stem cutting followed by herbicide and salt application, the scientists reported herbicide leaf treatment to be the most effective method. Manual removal by digging and treating stems with glyphosate showed medium effectiveness. Treating stems with a saturated salt solution appeared rather cosmetic. However, it’s not that easy to choose which method would be the best to work with, since with herbicide use there are non-target effects on the environment, economy, and society to be considered.
Dune restoration by mechanical removal of dense Oregon grape infestation (left) and leaf treatment of Oregon grape clone with a hand sprayer (right). Photo by Tim Adriaens.
“Individual clones are best treated with herbicide, large surface areas provide opportunities for landscape-scale ecological restoration, combining invasive shrub removal with sand dune creation,” further explains Tim Adriaens.
In Belgium, Oregon grape was first recorded in the wild in 1906 and naturalised in the period 1920-1950. It has been spreading rapidly since the 1990s. This expansion might be linked to cultivated hybrids and global warming, with the latter leading to a lengthened growing season, suggest the scientists. The species likes calcareous soils. Along the Belgian coast, Oregon grape has mainly invaded grey dunes, scrub and woodland.
Thanks to its numerous blue berries, which are easily dispersed over long distances by songbirds, the plant can appear everywhere within the dunes sites, also in places hardly accessible to managers. With the help of a highly branched root system, the plants attach themselves firmly in the sand, which makes manual pulling of mature plants hardly possible and labor-intensive.
“Dune managers and scientists across Europe should unite to draft alert lists and prioritise established alien species for management,” Tim says in conclusion.
In conclusion, the scientists highlight the importance of an EU-wide collaboration between scientific communities. Invasive species are not bothered by administrative borders and exchanging experiences on impact and management options is crucial to maintain dune ecosystems in good conservation status.
Coastal dunes in Belgium provide unique habitat to many Red listed species. Photo by Tim Adriaens.
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Original source
Adriaens T, Verschelde P, Cartuyvels E, D’hondt B, Vercruysse E, van Gompel W, Dewulf E, Provoost S (2019) A preliminary field trial to compare control techniques for invasive Berberis aquifolium in Belgian coastal dunes. NeoBiota 53: 41-60. https://doi.org/10.3897/neobiota.53.38183
The monk parakeet (Myiopsitta monachus), also known as the Quaker parrot, is another South American species, known from the temperate to subtropical regions of Argentina and neighboring countries. Photo by ParrotNet.
Non-native parrots can cause substantial agricultural damage and threaten native biodiversity, although impacts vary strongly depending on where these parrots have been introduced. Brought to Europe as pets, escaped or released parrots have established numerous wild populations across Europe. Tens of thousands of ring-necked and monk parakeets make up the bulk of Europe’s parrots, but several more species are gaining a foothold too.
A pan-European team of researchers, conservationists, wildlife managers and policy-makers worked together under the umbrella of ParrotNet, an EU COST Action, and have reviewed the available evidence on parrot damage, concluding that measures to prevent parrots from invading new areas are paramount for limiting future harm. Their findings are published in the open-access journal NeoBiota.
The ring-necked parakeet (Psittacula krameri), also known as the rose-ringed parakeet, originates in Africa and South Asia. Photo by ParrotNet.
Introduced parrots can damage the environment, but severe impacts remain rare and localised. So far, most reports of damage are linked to the widespread and locally abundant ring-necked and monk parakeets. Studies show that in their native ranges, both species can and regularly do inflict large crop losses, but in Europe, expectations of comparable widespread and severe damage to agriculture have so far failed to materialise.
In Europe, competition with native species presents a more serious problem, especially for ring-necked parakeets as they can compete with native species for food and breeding sites. Meanwhile, in the Americas, monk parakeets are notorious for the damage their stick nests cause to power infrastructures by catching fire, yet very little evidence for such problems exist in Europe.
Reported impacts for other parakeet species in Europe are virtually nonexistent, probably because these species have been introduced more recently and currently exist as relatively small and localised populations.
“It was already well known that introduced parakeets can cause damage. There is the oft-cited example of a vineyard in Surrey (UK) where ring-necked parakeets caused a loss of thousands of bottles of wine. In Seville (Spain), the same parakeet species is threatening an endangered native bat population by evicting them from their roosting tree cavities. Our review of all reported impacts however shows that such severe damage is not the norm. In most cases, parakeets introduced to Europe only do limited damage and, for example, about half of the studies focusing on competition between introduced parakeets and native species explicitly report no evidence of impact.”
The study also highlights that differences in the type of damage, and the way they are reported and summarised influences the outcomes of invasive species impact assessments.
The generalised threat level that invasive species pose is often based on their worst known impacts, whilst the capabilities of a species to do damage often requires specific circumstances. While this is relevant information for identifying those invaders that can potentially have major impacts, it is not necessarily representative of the impacts the species is likely to have when introduced to a new area. Similarly, including damage reports from the native range or from other invaded ranges typically results in higher threat level estimates compared to what actually has been observed in Europe.
What can be done to mitigate parakeet impacts?
The Alexandrine parakeet (Psittacula eupatria), also known as the Alexandrine parrot, occupies a natural range that extends from Afghanistan to Vietnam, including all of India, Sri Lanka and the Andaman Islands. Photo by ParrotNet.
Based on the results of the study, the ParrotNet members also published a ‘policy brief’, summarising and discussing the implications of their findings for policy makers and wildlife managers. Their recommendations include stricter regulation aimed at preventing parakeet introductions, rapid response when emerging populations are detected and better dissemination of information to the public about the impact parakeets can have. For example, using bird feeders that parakeets cannot access may help reduce the abundance of these birds in cities.
“What should be done to minimise damage by invasive parakeets is ultimately up to policy-makers. But as scientists, we stress that our work again highlights that the best way to combat invasive species is to prevent their introduction and spread. Parakeet populations have already been successfully removed, for example, from islands such as the Seychelles, demonstrating that it is possible to stop them when prompt and decisive action is taken by governments. For the already established and large parakeet populations that can be found across parts of Europe, there is no ‘silver bullet’ solution to the problems they may locally pose. More applied research is needed to find cost-effective and acceptable methods to reduce parakeet impacts in those areas where they do cause damage”.
The nanday parakeet (Aratinga nenday), also known as the black-hooded parakeet, is a species native to South America. Photo by ParrotNet.
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Original source:
White RL, Strubbe D, Dallimer M, Davies ZG, Davis AJS, Edelaar P, Groombridge J, Jackson HA, Menchetti M, Mori E, Nikolov BP, Pârâu LG, Pečnikar ZF, Pett TJ, Reino L, Tollington S, Turbé A, Shwartz A (2019) Assessing the ecological and societal impacts of alien parrots in Europe using a transparent and inclusive evidence-mapping scheme. NeoBiota 48: 45-69. https://doi.org/10.3897/neobiota.48.34222
Durban Harbour, used for both commercial and recreational purposes, is an important hub of human activity. The harbour was found to be an important point of first introduction as well as a site for naturalisation for the three species highlighted in this study. (Photos by Şerban Procheş /left/ and Carl Munsamy /right/)
While exploring the way alien species invade cities around the world, South African PhD student Ashlyn L. Padayachee (University of KwaZulu-Natal, UKZN) and her supervisors, Serban Proches (UKZN) and John Wilson (SANBI and Stellenbosch University) remember suddenly being stricken.
What they realised was that while cities were gradually starting to prepare for climate change, their responses to invasions were rather reactive. Even though management focused on widespread invasive species, which were currently having the most negative impacts on native biodiversity, the researchers noted that if those decision makers had only targeted the next highly damaging invaders ahead of their arrival, the associated costs would have greatly decreased.
Consequently, the team developed a methodology, based on three key aspects: priority species, points of first introduction and sites of naturalisation, in order to identify the most probable and concerning invasive species for Durban (eThekwini in KwaZulu Natal), a coastal city in South Africa. Furthermore, their work, published in the open-access journal Neobiota provides decision makers from around the world with a new tool, that is easy to use and adjustable to the specificity of different cities.
Firstly, the researchers identified cities with a similar climate to Durban and used existing alien species watch lists, environmental criteria and introduction pathways to identify species, which are not present in South Africa, but are considered of unacceptable risk of invasion. The team continued by figuring out which of those selected species are likely to have pathways facilitating their introduction to the city and developed a climatic suitability model for each. Finally, the scientists linked the climate and pathway information, so that they could identify sites within Durban to be considered as a focus for the contingency planning for particular species.
As a result, the authors identified three alien species as priorities for Durban: Alligator weed (Alternanthera philoxeroides), American bullfrog (Lithobates catesbeianus) and the red imported fire ant (Solenopsis invicta).
River systems are ideal habitats for Alligator weed. River systems adjacent to points of first introduction were identified as important sites of first naturalisation of this species. (Photo by Şerban Procheş)
In terms of points of introductions, the data highlighted the Durban Harbour, especially for the red imported fire ant. Plant nurseries and garden centres, as well as pet and aquarium shops were also identified as important sites for the three studied species. Additionally, suitable habitats located near the points of introduction, such as river systems and built infrastructure, were found in need of monitoring.
The red imported fire ant is usually found in close proximity to human dwellings, which provide ideal habitats for this species. Built infrastructure, especially those adjacent to the Durban Harbour, was identified as an important site of its naturalisation. (Photo by Şerban Procheş)
In conclusion, the implementation of prioritisation schemes to consider the three aspects (species, pathways, and sites) allows managers to focus resources on those species which pose a greater risk of invasion and impact.
“This will only ever be one part of a broad range of biosecurity efforts, but it is one where, we believe, we can be prepared,” comment the authors.
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Original source:
Padayachee AL, Proches S, Wilson JRU (2019) Prioritising potential incursions for contingency planning: pathways, species, and sites in Durban (eThekwini), South Africa as an example. NeoBiota 47: 1-21. https://doi.org/10.3897/neobiota.47.31959
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’.
