Roadside invader: the higher the traffic, the easier the invasive common ragweed disperses

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

Citizen scientists help expose presence of invasive Asian bamboo longhorn beetle in Europe

A worryingly high number of Asian bamboo longhorn beetles turn out to have been emerging across Europe for about a century already, finds an international research team. Curiously, the records of the invasive, non-native to the Old Continent species are mostly sourced from citizen scientists and online platforms, which proves the power of involving the public in species monitoring. The study is published in the open-access, peer-reviewed scientific journal BioRisk.

A worryingly high number of Asian bamboo longhorn beetles (Chlorophorus annularis) turn out to have been emerging across Europe for about a century already, finds an international research team, headed by researchers from the Center of Natural History, University of Hamburg, Germany. Curiously, the recent records of the invasive, non-native to the Old Continent species are mostly sourced from citizen scientists and online platforms, which proves the power of involving the public in species monitoring. The study is published in the open-access, peer-reviewed scientific journal BioRisk.

In our globalised world, which has already become victim to climate change and biodiversity loss, non-native species present a further threat to our ecosystems. Thus, the rising accounts of newly recorded alien species are of serious concern to both scientists and (inter)national institutions. However, surveying non-native species remains limited to a small fraction of species: those known to be particularly invasive and harmful.

One of the multitude of non-native species that are currently lacking efficient and coordinated surveying efforts is the Asian bamboo longhorn beetle (Chlorophorus annularis). Naturally occurring in temperate and tropical Southeast Asia, the insect feeds on a variety of plants, but prefers bamboo. Thus, due to the international trade of bamboo and the insects ‘travelling’ with the wood, the species has continuously been expanding its distribution around the world. Its first appearance in Europe was recorded back in 1924, when it was identified in England.

Bamboo longhorn beetle captured in Braintree, United Kingdom
Photo by Stephen Rolls

Back to our days, during a fieldwork practice for students at the University of Hamburg, held within the city because of the COVID-19 travelling restrictions, the team stumbled across a longhorn beetle, later identified by scientists as the Asian bamboo borer. Furthermore, it became clear that there were even more recent records published across different citizen science platforms, such as iNaturalist, iRecord and Waarneming.nl. Having taken the contacts of the citizen scientists from there, the researchers approached them to ask for additional collection details and images, which were readily provided. As a result, the researchers formally confirmed the presence of the Asian bamboo borer in Belgium and the Netherlands. In total, they reported thirteen new introductions of the species in Europe, which translates to a 42% increase of the records of the species for the continent.

“In light of the warming climate and a growing abundance of ornamental bamboo plants in Europe, the beetle might get permanently established. Not only could it become a garden pest, but it could also incur significant costs to the bamboo-processing industry,”

comments Dr Matthias Seidel, lead author of the study.

Having realised the potential of citizen science for bridging the gaps in invasive species monitoring, the researchers now propose for specialised platforms to be established with the aim to familiarise non-professional scientists with non-native species of interest and provide them with more sophisticated reporting tools. The aim is to speed up the identification of important alien species by collating records of specific species of interest, which are flagged and regularly exported from other citizen science databases and platforms. 

Bamboo longhorn beetle captured in Lincoln, United Kingdom
Photo by Sheena Cotter

Original source: 

Seidel M, Lüttke M, Cocquempot C, Potts K, Heeney WJ, Husemann M (2021) Citizen scientists significantly improve our knowledge on the non-native longhorn beetle Chlorophorus annularis (Fabricius, 1787) (Coleoptera, Cerambycidae) in Europe. BioRisk 16: 1–13. https://doi.org/10.3897/biorisk.16.61099

Australia’s wish list of exotic pets

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”,

shares the lead author Mr. Adam Toomes from the University of Adelaide.

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

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A new species of black endemic iguanas in Caribbeans is proposed for urgent conservation

A newly discovered endemic species of melanistic black iguana (Iguana melanoderma), discovered in Saba and Montserrat islands, the Lesser Antilles (Eastern Caribbean) appears to be threatened by unsustainable harvesting (including pet trade) and both competition and hybridization from escaped or released invasive alien iguanas from South and Central America. Scientists call for urgent conservation measures in the article, recently published in the open-access journal Zookeys.

A newly discovered endemic species of melanistic black iguana (Iguana melanoderma), discovered in Saba and Montserrat islands, the Lesser Antilles (Eastern Caribbean), appears to be threatened by unsustainable harvesting (including pet trade) and both competition and hybridization from escaped or released invasive alien iguanas from South and Central America. International research group calls for urgent conservation measures in the article, recently published in the open-access journal Zookeys.

So far, there have been three species of iguana known from The Lesser Antilles: the Lesser Antillean iguana (Iguana delicatissima), a species endemic to the northernmost islands of the Lesser Antilles; and two introduced ones: the common iguana (Iguana iguana iguana) from South America and the green iguana (Iguana rhinolopha) from Central America.

The newly described species is characterised with private microsatellite alleles, unique mitochondrial ND4 haplotypes and a distinctive black spot between the eye and the ear cavity (tympanum). Juveniles and young adults have a dorsal carpet pattern, the colouration is darkening with aging (except for the anterior part of the snout). 

A basking iguana optimizing after different trials its warming by a curved position when the sun is low on the horizon on the Windward coast of Saba.
Сredit: M. Breuil
License: CC-BY 4.0

It has already occurred before in Guadeloupe that Common Green Iguana displaced the Lesser Antilles iguanas through competition and hybridization which is on the way also in the Lesser Antilles. Potentially invasive common iguanas from the Central and South American lineages are likely to invade other islands and need to be differentiated from the endemic melanistic iguanas of the area.

The IUCN Red List lists the green iguana to be of “Least Concern”, but failed to differentiate between populations, some of which are threatened by extinction. With the new taxonomic proposal, these endemic insular populations can be considered as a conservation unit with their own assessments.

“With the increase in trade and shipping in the Caribbean region and post-hurricane restoration activities, it is very likely that there will be new opportunities for invasive iguanas to colonize new islands inhabited by endemic lineages”,

shares the lead researcher prof. Frédéric Grandjean from the University of Poitiers (France).
Iguana melanoderma sunbathing at dawn on the Windward coast of Saba.
Сredit: M. Breuil
License: CC-BY 4.0

Scientists describe the common melanistic iguanas from the islands of Saba and Montserrat as a new taxon and aim to establish its relationships with other green iguanas. That can help conservationists to accurately differentiate this endemic lineage from invasive iguanas and investigate its ecology and biology population on these two very small islands that are subject to a range of environmental disturbances including hurricanes, earthquakes and volcanic eruptions.

“Priority actions for the conservation of the species Iguana melanoderma are biosecurity, minimization of hunting, and habitat conservation. The maritime and airport authorities of both islands must be vigilant about the movements of iguanas, or their sub-products, in either direction, even if the animals remain within the same nation’s territory. Capacity-building and awareness-raising should strengthen the islands’ biosecurity system and could enhance pride in this flagship species”,

concludes Prof. Grandjean.

The key stakeholders in conservation efforts for the area are the Dutch Caribbean Nature Alliance (DCNA), the Saba Conservation Foundation (SCF), the Montserrat National Trust (MNT) and the UK Overseas Territories Conservation Forum (UKOTCF), which, the research team hope, could take measures in order to protect the flagship insular iguana species, mainly against alien iguanas.

Geographical distribution of the three iguana groups identified by Lazell (1973) in the 1960s and new taxonomic proposition.
Credit: Breuil et al. (2020)
License: CC-BY 4.0

***

Original source:

Breuil M, Schikorski D, Vuillaume B, Krauss U, Morton MN, Corry E, Bech N, Jelić M, Grandjean F (2020) Painted black: Iguana melanoderma (Reptilia, Squamata, Iguanidae) a new melanistic endemic species from Saba and Montserrat islands (Lesser Antilles). ZooKeys 926: 95-131. https://doi.org/10.3897/zookeys.926.48679

Contact:

Frédéric Grandjean 
Email: frederic.grandjean@univ-poitiers.fr

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

***

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

Faster than a speeding bullet: Asian hornet invasion spreads to Northern Germany

Known to prey on many insects, including honey bees and other beneficiary species, the Asian hornet, which had recently invaded parts of Europe, presents a serious threat to apiculture and even to ecosystems. In their paper, published in the open-access journal Evolutionary Systematics, German scientists share concerns about this fast invader spreading to the north. In early September 2019, a single specimen was collected alive in Hamburg (Germany), representing the northernmost find of the species so far.

In early September 2019, an Asian hornet (Vespa velutina nigrithorax) was collected alive in Hamburg, Germany, representing the northernmost find of the species so far in Europe and indicating its further spread to the north. The paper by the research group from Hamburg, which also serves to update the occurrence of the dangerous invader, was published in the open-access journal Evolutionary Systematics

Known to prey on many insects, including honey bees and other beneficiary species, the Asian hornet, which had already invaded parts of Southern and Central Europe, is a potential threat to apiculture and even to ecosystems. 

The first specimen was captured in south-western France in 2005 and started to spread quickly. Over the next years, it invaded large parts of France and regions of Spain, Portugal, Belgium, Italy, the Netherlands, Great Britain and south-western parts of Germany. The estimated invasion speed for France has been estimated at around 78 km/year, but in reality, the species spread might be occurring much faster due to anthropogenic factors.

It’s not yet clear if the collected Asian hornet belonged to an already settled population or it’s rather the first record of a new invasion. Nevertheless, considering the fast invasion speed of the species and its relatively high climatic tolerance, it’s quite possible that it had reached Hamburg on natural routes and now reproduces there.

Even though other models suggest that the Hamburg area is not suitable for the species today, the new find might be a sign that the Asian hornet has begun spreading at a speed above that previously known and even in climatically less favourable regions.

“Therefore, the current find needs to be taken seriously, no matter if it is only a single specimen or a member of an established population”, shares the lead researcher Martin Husemann from Centrum für Naturkunde, University of Hamburg.

Invasive species are one of the great challenges in the modern world. Their occurrence can be considered as one of the key important ecological and evolutionary drivers.

***

Original source:
Husemann M, Sterr A, Maack S, Abraham R (2020) The northernmost record of the Asian hornet Vespa velutina nigrithorax (Hymenoptera, Vespidae). Evolutionary Systematics 4(1): 1-4.
https://doi.org/10.3897/evolsyst.4.47358



Experiment suggests the best ways to tackle invasive Oregon grape in Belgian coastal dunes

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 dunesshifting 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

Be prepared: Prioritising invasive species for strategic prevention in Durban, South Africa

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

Living room conservation: Gaming & virtual reality for insect and ecosystem conservation

Gaming and virtual reality could bridge the gap between urban societies and nature, thereby paving the way to insect conservation by the means of education and participation. This is what an interdisciplinary team at Florida International University strive to achieve by developing a virtual reality game (desktop version also available) dedicated to insect and plant species. Focused on imperiled butterflies, their innovative idea: Butterfly World 1.0, is described in the open-access journal Rethinking Ecology.

Participant playing the virtual reality version of Butterfly World 1.0.
Photo by Jaeson Clayborn.

Players explore and search for butterflies using knowledge gained through gameplay

Gaming and virtual reality (VR) could bridge the gap between urban societies and nature, thereby paving the way to insect conservation by the means of education, curiosity and life-like participation.

This is what Florida International University‘s team of computer scientist Alban Delamarre and biologist Dr Jaeson Clayborn strive to achieve by developing a VR game (desktop version also available) dedicated to insect and plant species. Focused on imperiled butterflies, their innovative idea: Butterfly World 1.0, is described in the open-access journal Rethinking Ecology.


When playing, information about each butterfly species is accessed on the player’s game tablet. Image by
Alban Delamarre and Dr Jaeson Clayborn.

Butterfly World 1.0 is an adventure game designed to engage its users in simulated exploration and education. Set in the subtropical dry forest of the Florida Keys (an archipelago situated off the southern coast of Florida, USA), Butterfly World draws the players into an immersive virtual environment where they learn about relationships between butterflies, plants, and invasive species. While exploring the set, they interact with and learn about the federally endangered Schaus’ swallowtail butterfly, the invasive graceful twig ant, native and exotic plants, and several other butterflies inhabiting the dry forest ecosystem. Other nature-related VR experiences, including conservation awareness and educational programs, rely on passive observations with minimal direct interactions between participants and the virtual environment.

According to the authors, virtual reality and serious gaming are “the new frontiers in environmental education” and “present a unique opportunity to interact with and learn about different species and ecosystems”.


In the real world, Spanish needles (Bidens alba) is considered a weed in South Florida. However, it is an excellent nectar source for butterflies.
Photo by Alban Delamarre.

The major advantage is that this type of interactive, computer-generated experience allows for people to observe phenomena otherwise impossible or difficult to witness, such as forest succession over long periods of time, rare butterflies in tropical dry forests, or the effects of invasive species against native wildlife.

“Imagine if, instead of opening a textbook, students could open their eyes to a virtual world. We live in a time where experiential learning and stories about different species matter, because how we feel about and connect with these species will determine their continued existence in the present and future. While technology cannot replace actual exposure to the environment, it can provide similar, near-realistic experiences when appropriately implemented,” say the scientists.

In conclusion, Delamarre and Clayborn note that the purpose of Butterfly World is to build knowledge, reawaken latent curiosity, and cultivate empathy for insect and ecosystem conservation.

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The game is accessible online at: http://ocelot.aul.fiu.edu/~adela177/ButterflyWorld/.

Original source:

Clayborn J, Delamarre A (2019) Living room conservation: a virtual way to engage participants in insect conservation. Rethinking Ecology 4: 31-43. https://doi.org/10.3897/rethinkingecology.4.32763

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.