November 29, 2016

The aliens’ way of life and the secret of (invasion) success

What do mynas, cane toads, guppies, Pacific lionfish, ants and signal crayfish have in common? As it emerges from the new book published by the Cambridge University Press, Biological Invasions and Animal Behaviour, they share the “perfect” behavioural traits that make them successful invaders. They are only a selection of the many species used as examples and case studies of this volume edited by Judith S. Weis and Daniel Sol, which gathers together several contributions from scientists across the world, covering a broad range of disciplines. The purpose is to provide a comprehensive  overview of the benefits of adding behavioural perspectives in biological invasions, for example for understanding why some species are more likely than others to succeed in a new environment, and also to foresee and analyse the relevant impacts.


The role of animal behaviour in facilitating the invasion process has probably been overlooked in the past, according to the editors. But in recent years scientists have been looking at the behaviour of alien species with growing interest.  As highlighted in the very inspiring volume edited by Weis and Sol, more emphasis is now put on the role of behavioural flexibility as a mechanism for succeeding across the various stages of invasion, i.e. from transport to impact. The study of animal behaviour, and how the cognitive process facilitates the invasion success, is key to understanding the factors which are supposedly influencing the likelihood that introduced species will establish and spread. For example, amateur aquarists know very well that it is almost impossible not to breed guppies. As pointed out by Andrea S. Griffin and colleagues, this is due to the very adaptable mating strategy of this tropical fish, also in novel environments. Guppies are very popular aquarium fish and are often released in the wild as unwanted pet release, or introduced intentionally for mosquito control, but opportunity alone would not be sufficient to explain their invasion success. Behavioural flexibility and remarkable plasticity in mating behaviour allow immediate adjustments in response to novel circumstances, thus it is not surprising to know that this species native to South America is now established in over 70 countries outside its native range.



Red swamp crayfish (Procambarus clarkii) © Photo: Riccardo Scalera

The recurring behavioural traits which favour the successful invasion of a number of alien species are discussed in detail throughout the 18 chapters of the book. Invasive alien crayfish are another example. As Elena Tricarico and Laura Aquiloni describe in their exhaustive review, many species belonging to this group are highly flexible and adaptable, able to display new and different behaviours in new habitats. They actively and widely disperse, and can avoid predation, even from new predators, thanks to their ability to respond adaptively to a wide range of predation risk cues. They are also characterised by flexible feeding habits (as they are usually omnivorous and voracious), aggressive behaviour, some hybridisation potential, and are highly prolific and able to identify mates also in challenging conditions (e.g. despite long distances and turbid waters).  Additionally, likewise many other groups of alien species, may even display personality traits that further enhance invasion abilities.


The book also emphasises the value to pay attention to how indigenous species are learning to live with the threat posed by invasive species. For example, a chapter by Ignasi Bartomeus and colleagues provides some useful insights on the role of behaviour flexibility and cognitive capabilities of pollinators in the process of adapting to novel environments dominated by alien plants.  Another fundamental contribution is the chapter by Martina Carrete and José L. Tella, who stress how the prevalence of some group of species over others in international trade (i.e. parakeets), suggests that the possession of particular traits may contribute to increase the likelihood of a species being traded. Here the point is the “attractiveness” (for people), although most species would not know much about etiquette and good manners (the perceived behaviour of most alien species would hardly fall into the category of socially acceptable and respectful).


However, this confirms the importance of human behaviour as a key driver of the movement of species outside their natural range, which explains the strong focus of the current nature conservation policies on the identification, prioritisation and management of alien species pathways. But, as already pointed out, this cannot explain why certain species or group of species are more successful than others in establishing self sustaining populations into new environments. Under a mere management perspective this evidence may have fundamental implications. As a matter of fact, while we may change our (human) attitude towards the problem, e.g. by introducing strong social norms to prevent further introductions, we need scientifically sound and reliable insights on alien species behaviour to define key management recommendations and direct future research on invasion biology. In this sense the book is a clear invitation to increase effort to focus future research activities on animal behaviour, and sheds new lights on the role of ethologists as key allies of conservation biologists.

November 14, 2016

Managing alien species pathways and vectors

Shipping and recreational boating, the movement of live bait and fire wood, cargo transport and wildlife trade, are only some of the pathways and vectors through which alien species are moved outside their natural range by humans. Transport, trade, travel and tourism provide vectors and pathways for live animals, plants, and other biological material to overcome those biogeographical barriers that would usually block their movement and spread. Given the multitude of such pathways and the variable impact they have, it is necessary to prioritize those pathways with the greatest impact on biodiversity and possibly manage them appropriately to enhance the prevention of biological invasions. 

Canada goose in "flight" © Photo: Riccardo Scalera

The importance of the threat of invasive alien species (IAS) pathways is reflected in a range of international, regional and national laws and agreements. For example, Target 9 of the Strategic Plan for Biodiversity 2011-2020 - adopted by the Convention on Biological Diversity (CBD) at the 10th COP - states: “By 2020, invasive alien species and pathways are identified and prioritized, priority species are controlled or eradicated, and measures are in place to manage pathways to prevent their introduction and establishment”. At the European level, the same goal is reported within target 5 of the Biodiversity Strategy to 2020 of the European Union (EU). As a result, all EU Member States, following the recent adoption of the EU Regulation on IAS, are required to develop action plans for the management of pathways: a significant improvement in the coordination, implementation, and consistency of pathway management across the region.

Also the Council of Europe provided significant support in this context. Since the development of the European Strategy on IAS in 2003, the Group of experts on Invasive Alien Species established by the Standing Committee to the Bern Convention in 1992,  has focussed its work on the identification and prioritisation of pathways, and started preparing targeted codes of conduct to address these. So far the Standing Committee has endorsed codes of conduct on IAS and activities such as horticulture, zoos and aquaria, botanic gardens, hunting, pets or recreational fishing (all codes are available here under documents/publications). Other codes are under development, including on plantation forestry and recreational boating. More recently, as reported by Recommendation N°179 (2015), the Bern Convention identified a number of activities to be carried out in coordination with the European Commission (EC), among which the possibility to draft a Guidance document on action plans for the management of IAS pathways.


The guidance document on IAS pathways action plans

The result is a document including three sections, namely an introduction (with an overview of the available information on identification, prioritisation and management of IAS pathways, along with preliminary results and future challenges on assessing priority pathways), a section describing the most relevant policy and legislation, and a core body including the actual guidelines on how to draft an action plan for dealing with IAS pathways. The following key sections of an ideal acton plan are described in the detail in the document of the Council of Europe:
  • Description of the target pathway
  • Policy and legal background
  • Aims and strategies
  • Identification of key stakeholders
  • Foreseen measures (Specific measures depending on the IAS  pathway targeted, Common measures for all management/action plans for IAS pathways)
  • Time schedule
  • Financial planning
Besides the elements of an ideal plan, the guidance document describes further elements to take into account for facilitating the management of the planning process, stressing the importance of a sound pre-planning phase.

Although the need of such guidance was inspired by the provisions of the EU regulation on IAS, the interest of this work is not to be considered limited to the EU Member States. This fits well with the Bern Convention role to further outside the EU the innovation of the EU Regulation on IAS, and represents another step in the process led by the Council of Europe in drafting key IAS related documents over the years, by stressing the added value of ensuring a harmonised approach in the region.

January 14, 2015

Protecting animal migration routes from biological invasions

Habitat destruction, climate change, unsustainable hunting and fishing practices, and barriers such as roads, power lines, dams, and wind farms, are some of the main factors affecting the conservation and sustainable use of migratory animals and their habitats. The Convention on the Conservation of Migratory Species of Wild Animals (CMS) is a framework treaty specialized in the conservation of migratory species, their habitats and migration routes, through a number of global and regional agreements focusing on specific topics and implemented throughout the migratory range of the target species (those that need or would significantly benefit from international co-operation). Invasive alien species (IAS) are another major threat to migratory species, and it is expected that following the adoption - at the 11th Meeting of the Conference of the Parties (held in Quito, on 4-9 November 2014) - of Resolution 11.28 on “Future CMS Activities related to Invasive Alien Species” they will be receiving greater attention from the CMS. The resolution is based on the results of a technical report commissioned by the UNEP/CMS titled “Review of the Impact of Invasive Alien Species on Species protected under the Convention on Migratory Species (CMS)” undertaken by the IUCN/SSC Invasive Species Specialist Group (ISSG), whose key findings are briefly presented below (a former version of the report is available here).

Free-flying colony of sacred ibis in a zoo in Northern Italy © Photo: Riccardo Scalera

According to the study over one third of species included within the CMS appendixes are under some level of threat from IAS, with seabird and marine turtle populations in their breeding/nesting grounds on island ecosystems being most under the threat of IAS. In total, 78 IAS have been recorded as having some measure of impact on CMS listed species, e.g. through predation, competition and genetic changes caused by hybridization, as well as through the transmission of diseases, impairment of breeding and by causing loss of habitat and resources crucial for migratory species. The top ten IAS include introduced mammal predators - such as cats, rats, dogs, pigs, and house mouse - and introduced herbivores - such as European rabbits, goats and domestic livestock. The spread of invasive alien plants, such as grasses and macrophytes, are another cause of habitat alteration and loss, as they may alter habitats of bird species through competition and displacement of native plants. An example is the intentional introduction of ornamental and “useful” plants such as the ironwood (planted for erosion control and as wind breaks along coastland), which is also known for its impacts on dune ecosystems, on native dune plants and nesting grounds of turtles. The spread of alien pathogens is also a serious threat to migratory species. For example migratory bird species especially waterfowl, shorebirds and gulls are both victims and vectors of the highly pathogenic avian influenza. Interspecific hybridisation is a concern among sturgeon populations.

The sacred ibis: a conservation paradox © Photo: Riccardo Scalera

The risk of migratory species to become invasive themselves if translocated and/or introduced outside their natural range, can help understand the complexities which characterize the interactions between IAS and threatened migratory species. For example, the sacred ibis, a native to Sub-Saharan Africa and the Middle East, is a kind of “conservation paradox” for although it is protected by the CMS, outside its native range is considered a threat to other species, including those protected by the CMS itself. In Europe, where breeding populations of this intra-African migrant are known in Spain (including the Canary Islands), France and Italy, the sacred ibis has been recorded as predating eggs and affecting seabird colonies of sandwich terns, common terns and black terns, all CMS appendix II species. There are other CMS listed species introduced outside their native range, which could represent a threat for the native biodiversity. Examples are the beluga whale and the grey seal, introduced outside their native range in the Black Sea (which are CMS Appendix II species, see previous post here), although no specific impacts have been recorded as yet.

An analysis undertaken to identify gaps and synergies of current policy initiatives in relation to IAS, showed that the inadequate action related to the management of IAS is not a result of gaps in international policy but rather it is caused by inadequate enforcement at national level. A more systematic cooperation between different global conventions and multilateral environmental agreements would definitely provide greater and more effective opportunities to address biodiversity issues, including those measures to prevent the introduction and spread of the most harmful species. In this context, key recommendations of CMS Resolution 11.28 include the improvement of understanding of interactions between IAS and threatened migratory species; the development of priorities for intervention; the improvement in international cooperation and the development of adaptable management strategies (including prevention, control, eradication, etc.) when discussing topics for which IAS might be relevant. Other fundamental provisions focus on the need to avoid policies and initiatives that limit the use of effective measures to eradicate or control IAS (or facilitate their introduction and further spread); the importance to take into account the risk of facilitating the introduction or spread of IAS while implementing any climate change mitigation or adaptation measures; the identification of potential strategic partners and relevant stakeholders for developing information campaigns and other outreach activities; and of course the mobilization of appropriate resources for the implementation of the measures directed at dealing with IAS issues in relation to migratory species.

December 15, 2014

The "birds" may have the right but the cat has the claws

The tale of Stephens Island wrens, driven to extinction by a single cat owned by the local lighthouse keeper, has become a very popular legend among conservationists. The true facts behind this legend are not very different, as this unique nocturnal, flightless bird which lived nowhere else on the planet, was apparently exterminated by feral cats, although more than a single one. In fact, in Stephens Island cats became established in 1894, and after increasing in numbers dramatically affected several species. Stephens Island provides the classic example of the effect that predation by feral cats can have on an island land bird fauna. But this is a problem of global concern. In New Zealand, like in several other countries worldwide, islands experienced a rapid demise of the native land bird fauna due to cat predation. With just a little more care, and a thorough knowledge and understanding of the problem, many islands may have remained a safe haven for many species now disappeared. In this context, a new book published by Wiley "Free-ranging cats. Behavior, ecology, management" (by Stephen Spotte) provides a comprehensive and objective insight on the key topics related to the management of feral cats, addressing some fundamental issues for a correct analysis of the problem, including a review of the available information on the species' behavioral, biological and ecological features. The message is clear: we should stop further irreversible biodiversity losses due to cat predation, and we have the proper knowledge to deal with it. The book represents an optimal guidance tool for all those who are interested in a sound understanding of the issue, whether the focus be on cats or the wide range of little animals they prey upon, or both.




Cats are generalist predators that once introduced to the wild (or simply allowed to roam outdoor), can prey on a variety of native species, which may suffer severe population declines and even face extinction. On this regard, it makes no difference whether the cats are owned (in which case their impact might be even more subtle, because often unnoticed), stray or feral: as stated by George F. Will (American journalist, and author) The phrase "domestic cat" is an oxymoron. The result is that at the global level, cats are considered responsible for at least 14% of bird, mammal and reptile extinctions and are the principal threat to almost 8% of critically endangered birds, mammals and reptiles. The figures are impressive. In continental Australia and its offshore islands there are some 15-23 million feral cats which are estimated to eat about 75 million native mammals, reptiles, birds and even insects a night, more than 20 billion every year (see here for details). These astonishing figures are very similar to the results of a study made in the US. Also in Britain, estimates derived from scaling up local studies to the national level show that cats kill 25–29 million birds per year. It is easy to imagine how detrimental this species can be, considering that cats have been introduced to about 179,000 islands worldwide. According to another recent study, the impacts of feral cats is known from at least 120 different islands on at least 175 different species of vertebrates (25 reptiles, 123 birds, and 27 mammals), many of which are listed on the IUCN Red List. For example, in the Canary Islands, four species (one endemic bird — the Fuerteventura stonechat — and three endemic giant lizards) out of a total of 68 species (including invertebrates) identified as preys are considered threatened (for a review on the impact of cats and other invasive alien species, see the EEA technical report No 16/2012 discussed here). 


Stray cat in Rome © Photo: Riccardo Scalera

Cats are predators and are not to be blamed for this, but people and particularly cat owners could do more to prevent all this to happen. Prevention would be the most effective and easy option to ensure a reduced predation of cats on small mammals and birds (not to consider reptiles and amphibians, and a number of invertebrates) and raising awareness  should be a fundamental step in any nature conservation campaign. Otherwise, there is no doubt that the more effective way to prevent exacting such a heavy toll on native wildlife would be the implementation of policies to prevent the establishment of feral cats and their colonies in (semi)natural environments (see for example the Australian 2008 threat abatement plan predation by feral cats). This could save millions, if not billions, of birds and other animals, yet for many people might inevitably sound inconceivable. For those pet lovers who consider cats as family members, it may be difficult to believe that their companion pets may turn into such harmful threat to biodiversity. In fact, cat owners should make a special effort to acknowledge the problem and ensure keeping their pets indoors. Whenever this is not feasible, an alternative partial solution would be to fit cats with quick-release collars equipped with a bell or other deterrents (like bibs), which may significantly reduce predation rates on small mammals and birds (although cats can learn to silently stalk their prey anyway). 

The implementation of effective control measures on feral cats can be a challenging task. First of all, to maintain the necessary political/public support and funding, it is pivotal to consider humane, socially acceptable options, including ways to avoid or minimize methods that cause animal suffering or affect domestic cats, particularly for the inherent problems associated with the opposition of citizens and animal welfare groups. Disregarding the importance of these aspects might lead to the failure of the operations. In addition, some drawbacks have been reported in situations where cats have been removed without taking into proper account the presence of other introduced species (such as rabbits, rats or mice). The risk is that some problems linked to hyperpredation and predator release effect may create trophic cascades leading to rapid, landscape-wide ecosystem changes. It was the case of the removal of cats on the sub-Antarctic Macquarie Island, which resulted in a significant increase in rabbit abundance (formerly reduced by cat predation), which in turn led to substantial local- and landscape-scale changes in vegetation. Although this trophic cascade was predictable given the history of rabbit impacts via grazing on both this and other islands and was not entirely unexpected, its extent was not fully anticipated. This episode (see here for details) shows the importance of carefully assessing the risks of management interventions and planning for their indirect effects.

June 18, 2014

LIFE confirms financial support to alien species policy in Europe

On 18 June 2014 a new LIFE call has been launched, and invasive alien species (IAS) continue to be a priority issue for funding within the European Union (see previous post on the 2013 call here). The new LIFE Regulation, which establishes the EU financial Programme for the Environment and Climate Action, with a total budget set at 3.4 billion euro for the funding period 2014–2020, has been throughly revised. For example, the programme is now subdivided in the two sub-programmes Environment and Climate Action. Besides, to ensures both the necessary flexibility to achieve the LIFE Programme targets and objectives and the necessary stability for potential applicants to plan, prepare and submit proposals, a Multiannual Work Programme for 2014-17 has been adopted. 

LIFE aims at contributing to the achievement of the objectives and targets of the Europe 2020 Strategy, the 7th Union Environmental Action Programme and other relevant EU environment and climate strategies and plans. In this context, and as reported more in detail below, IAS are explicitly mentioned in the list of project topics implementing the environmental policy priorities under the three priority areas covered within the new "Environment" strand: environment and resource efficiency; nature and biodiversity; and environmental governance and information.  It is also worth remarking that now the newly revised programme – which is open to the participation of third countries and activities outside the EU - consists of a number of new categories of projects, including preparatory projects, integrated projects, technical assistance projects, capacity building projects. The project topics set in the multi-annual work programme refer to "traditional" projects in the Environment sub-programme. "Traditional" projects are indeed very similar to the old LIFE+ Nature, Biodiversity, Environment and Information projects, e.g. focusing on best practice, demonstration, pilot, and information projects. 

More in detail, within the  priority area “Nature and Biodiversity” the project topics which are given priority to contribute to Target 1 of the Biodiversity Strategy to 2020 to fully implement the Birds and Habitats Directives, thus under the Thematic priorities for Nature, include:
Projects targeting invasive alien species, where these are likely to deteriorate the conservation status of species (including birds) or habitat types of Community Interest in support of the Natura 2000 network 
Priority is also given to project topics focus on the implementation of Targets 2, 3, 4 and 5 of the Biodiversity Strategy to 2020, thus under the Thematic priorities for Biodiversity, such as:
Projects implementing actions targeting Invasive Alien Species (under Target 5 of the Biodiversity Strategy or in view of contributing to reaching the level of protection set out in descriptor 2 — Non-indigenous species of the Marine Strategy Framework Directive (1)) through actions testing and applying approaches aimed at:(a) preventing the introduction of invasive alien species, in particular by tackling pathways of unintentional introduction,(b) establishing an early warning and rapid response system, and(c) eradicating or controlling established invasive alien species on an appropriate spatial scale.
These projects shall address with their actions the three steps (prevention; early warning and rapid response; eradication/control) in a comprehensive framework, or, where one of the steps has already been addressed, their actions shall at least be clearly situated in a broader framework that links all three steps. They should be set up to improve existing — or introduce new — technical, administrative or legal frameworks on the relevant level; they should aim at preventing the broader establishment of IAS within the EU.
Finally, the project topics listed under the priority area "Environmental Governance and Information", include:
National and transnational awareness raising campaigns on invasive alien species (IAS) targeting the general public and key stakeholders including policy makers, businesses, and local, regional or national authorities.
LIFE projects focusing on IAS across the years (source: EEA report no.15/2012)

The experience of the last 20 years has shown that LIFE has been crucial to ensure the successful implementation of several activities focusing on IAS management and prevention, including new ways to address the wider IAS challenge (see "LIFE and alien species" report here). In fact, as shown in a recent report on biodiversity indicators (EEA report no.15/2012), both the number of LIFE projects funded and the relevant cost estimates have been markedly positive across the years. The relevant data have been used for the development of a set of response indicators, whose role should be primarily to track the measures being implemented to mitigate pressures and improve the state of biodiversity.  This trend has been interpreted as reflecting an increasing awareness of the IAS problem among EU institutions, wildlife managers, scientific institutions, and citizens, but could also indicate that within the EU, the problem with IAS is increasing.  

Thus, in the light of the recent developments regarding the EU regulation on the prevention and management of the introduction and spread of IAS, the new call and the overall novelties introduced within the new LIFE Regulation, are very welcome. In fact the new EU regulation on IAS seeks to address the problem in a comprehensive manner so as to protect native biodiversity and ecosystem services, as well as to minimize and mitigate the human health or economic impacts that these species can have. The IAS legislation now needs only to be formally approved by the Council of Ministers (see details here), and there is a clear need of dedicated financial resources for the implementation of the foreseen types of provision focusing on prevention, early warning and rapid response, and management.

For the 2014 call 132,8 million euro out of a total budget of 404,6 million euro are for nature and biodiversity only, including related governance and information. The deadline for submitting proposals is 16 October 2014. You can find further information, application forms and all official guidance documents here.

February 04, 2014

Changing soundscapes. The spread of parakeets in Europe

This is going to be another “noisy spring”. The melodious notes of native black birds, wrens and robins are being progressively replaced in many European towns by the frequent loud screeching calls of monk parakeets and rose ringed parakeets. The genuine “soundscape” of European towns is indeed rapidly changing, replaced by the exotic calls of parakeets, which are becoming a familiar sound in many European cities, particularly in urban areas and parklands. Roosting sites are sometimes spectacular, as they may often contain several hundred birds attracted from a wide area to just a few trees. Nevertheless the screeching calls of parakeets in Europe, rather than being considered a mere novel fascinating thing, should remind us of the actual and potential threats they represent. In the old continent parakeets are not native species, as they have created breeding colonies only recently, further to intentional releases or accidental escapes of animals traded at least since the 60's as cage birds. Like many other invasive alien species, their presence can be detrimental to the environment and human welfare.


Monk parakeet (Myiopsitta monachus) in a cage
© Photo: Riccardo Scalera

Take for example the rose-ringed parakeets. This native to the African continent south of the Sahara and to south Asia, is now the most widely introduced parrot in the world (including at least 12 countries in Europe). In Europe, besides being a clear noise nuisance as already considered in some residential areas, can have a major impact on biodiversity, agriculture and even health. In fact rose-ringed parakeets may have detrimental effects on native birds with which they may compete, particularly in those habitats where the number of cavities as breeding sites is a limiting factor regulating population densities of cavity-nesters (e.g. for species like Eurasian nuthatch,  kestrel, stock dove, western jackdaw and common starling). 

In Europe most rose-ringed parakeet populations were initially introduced in urban environments, thus the impact on agriculture has been historically limited. However, they are now extending their range into rural environments, thus increasing the potential to become agricultural pests. Although the reports of parakeet damage to agriculture are still few, there is clear evidence of significant damage to crops as well. For example, in the United Kingdom rose-ringed parakeets damage buds and blossoms of various trees and shrubs. For this reason conflicts are known with fruit growers that experienced damage to apple, pear, cherries and plums. In addition, this parakeet has been reported to have damaged vineyards by reducing the expected wine production. Also in Australia, where the species is not native, rose-ringed parakeets are known to cause severe damage to plantations by stripping the bark from young stems and killing the affected trees, thus locally changing the arboreal composition. On the other hand, in at least part of its native range this species is considered one of the most destructive bird pests for agriculture. In India and Pakistan, for example, there are extensive reports of crop damage. 

Rose-ringed parakeet eating plums in Versailles
(Psittacula krameri)  © Photo: Riccardo Scalera

Rose-ringed parakeets are also possible vectors for diseases, like Newcastle's disease and cryptosporidium, which could be harmful to poultry and might also have an impact on that industry. Moreover, they could affect humans in the case of psittacosis. In any case, the potential for the parakeets to become serious pests in the future has been highlighted, in fact there is concern that farming practices that adapt to global climate change and a warmer Europe will facilitate the continued expansion of parakeet populations. As a consequence, given the detrimental impacts of parakeets occurring outside their natural range, it would be useful to monitor existing wild and captive populations, and to improve legislation to prevent deliberate introductions and escapes. Moreover, depending on the risks posed, population control or eradication may be considered necessary to limit the spread of the species and the potential for further damage. But this might be not very popular. The experience with the monk parakeet control in London (described here) is a good example of the challenges and opportunities of this option in Europe, with a special focus on the social dimension of the problem represented by this South American parakeet.

A dedicated EU project – ParrotNet - is just being launched with the aim to create a European network focusing on the impacts, drivers and monitoring of invasive parrots in Europe, and promoting the understanding of relevant invasion dynamics and risks to agriculture and society. ParrotNet is a COST Action, led by the University of Kent, UK, and will provide funding for a 4-year research network (for further information see here). The project, comprising currently 14 European countries, will help to (i) better understand why some species such as parakeets are highly successful invaders, (ii) harmonise methodologies to predict agricultural, economic, societal and ecological impacts across Europe, and the means to mitigate them, (iii) create a virtual European Monitoring Centre for all invasive parrot species, and (iv) transfer results to policy and society.  This is a key attempt to prevent that Carson's prophesy of a “silent spring” will be replaced in the near future by a more and more insidious “noisy spring”.

August 29, 2013

A silent invasion threatening European cities

The story of a rabbit population deep burrowing in a graveyard area, loosening the roots of trees, making tombstones fall, and horrifying people, may look like the plot of an old B horror movie. Yet, this is what the experts reported about the situation in Helsinki, where in 1985 rabbits established a feral population descended from pets dumped in the wild. Outside their natural range (the rabbit is native to the southern Iberian Peninsula), this species is considered as a key driver of ecosystem change, as it can cause extensive erosion of soils by overgrazing and burrowing which in turn can cause significant impact on the composition and local abundance of native wildlife. The impacts caused by this species can be very severe, also causing terms of economic losses. For example, until now the estimated economic impact of rabbit in Helsinki exceeds € 2 million. 

Feral rabbit © Photo: Riccardo Scalera

The rabbit is only one of the many alien species introduced in urban environments and whose impact is discussed in the new IUCN report “Invasive alien species: the urban dimensionThe IUCN report includes 26 case studies aimed at providing insights on problems, challenges, actions, approaches, human and financial resources, and lessons learnt, for a selection of species and countries. In fact the report was produced and released as a key output of the conference “Invasive alien species: the urban dimension” which will take place on 5 September at IUCN Headquarters, Switzerland. The objective of the conference is to emphasize the role of municipalities in the management of invasive alien species in urban environments, and more importantly, to highlight the importance of their contribution to the implementation of the new EU legislation for invasive alien species, which should finally be released in early September 2013. For more details and updated information on the conference and the upcoming EU legislation see here.


As shown by the many contributions published in the new IUCN report, urban environments – often characterised by high levels of disturbance, high intensity of transport, and high environmental heterogeneity - have usually played a crucial role in biological invasions. This is also due to the fact that within urban environments a number of potential entry points and pathways concentrate, such as botanical gardens and zoos, along with nurseries and private gardens. Besides, urban areas are privileged centres for some of the most prominent pathways and vectors, including trade of pets, ornamental plants, etc. which can increase the propagule pressure that facilitates the invasion processes. Not surprisingly, many studies have demonstrated that cities are hotspots of invasions, particularly for plants. Human settlements are often the point of origin of many invasive species, that from these areas then spread into adjacent landscapes along transport corridors such as railways, waterways and roads, in many cases eventually arriving to invade natural areas.

Drawing © Riccardo Scalera

It is clear that urban environments can play a much wider and important role in addressing the risks of biological invasions, e.g. for making citizens aware of the importance of biodiversity, and promoting the implementation of dedicated actions among the competent administrations. For example, many institutions usually based in towns, such as botanical gardens, zoos, aquaria, university departments, natural history museums, conservation agencies and institutions, can be key players in global conservation programmes, by and attracting and leveraging hundreds of millions citizens, thus contributing to public outreach and raising awareness. Many such institutions might offer unique opportunities for dedicated environmental education programmes, thus could contribute significantly to raising awareness to prevent the introduction of new invasive alien species (e.g. through specific information activities targeting the general public or specific stakeholders). Finally, as shown by the reported case study, local administrations can be players of fundamental importance for the successful implementation of conservation related activities, i.e. from research projects to eradication/control initiatives. 

June 05, 2013

Alarm for invasive hornet rapidly expanding European range


It was easy to predict the arrive of the Asian hornet in Italy. This invasive alien species native to South-East Asia, was recorded in Europe for the first time in France in 2004, where it was probably introduced accidentally through the horticultural trade. It spread very rapidly across south-western France (at around 100 km per year), and soon reached Spain, Portugal and Belgium. At the time the EEA report on invasive alien species impact was published (December 2012) it was considered likely to arrive soon also in Italy and Great Britain. In fact the news of the arrive of this hornet in Italy was circulated in May 2013, although the new record of the species originates from monitoring activities carried out already in November 2012 (see press release of the University of Turin). This shows that an effective early warning and rapid response system for alien species in Europe is urgently needed, so as to prevent further impacts related to biological invasions.

The Asian hornet © Photo courtesy of Quentin Rome

Invasion risk modelling already suggested that the Asian hornet - Vespa velutina or yellow-legged hornet to be more precise - could spread over a large part of Europe (see article published on Aliens no.31). And there are good reasons to be concerned about the spread of this “giant wasp”. With a body length of 2-3 cm Vespa velutina is in fact a social wasp slightly smaller than the native European hornet Vespa crabro. The head is black with an orange-yellow face. The body is dark brown or black velvety, bordered with a fine yellow band and a single abdominal segment almost entirely yellowy-orange, which makes it difficult to confuse with any other species.


The Asian hornet and its nest © Photo courtesy of Quentin Rome

The Asian hornet is mainly a predator of social wasps and bees, and like the European hornet, it also consumes a wide variety of other insect preys. Honeybees are among the hornet’s main preys, so the Asian hornet is expected to have an economic impact on beekeeping activities. In fact, as a highly effective predator, the new hornet may represent an additional component to the decline of honey bee populations in Europe and its big colonies and diet spectrum suggest that it could have a noticeable impact on biodiversity, including many wild pollinators and other beneficial insects. Otherwise, this species is no more dangerous for humans than the European hornet as in general it is not aggressive. However, its large size, painful sting and noisy flight make it a very frightening insect (and stings may potentially cause life threatening allergic reactions). In general, they will not attack as long as the colonies remain undisturbed, so it is necessary to avoid getting close to their very large nests, which are from 50 to 80 cm in diameter, and might be found in tall trees in urban and rural areas, including garages, sheds, and sometime in holes in walls or in the ground.

The life-cycle of this social insect is very efficient: each colony, initiated by a single individual, can produce several thousands of workers, plus hundreds of males and new founders able to mate and subsequently produce new colonies. Nevertheless research to develop an effective control method for Asian hornets is still in progress. You can find additional information about the species and the relevant management options, as well as the contact details for expert assistance on this link.

April 07, 2013

Marine mammals on their way to new seas

White whales and grey seals have found a new home in the Black sea. In fact one of the largest organism introduced by humans  outside its natural range is the beluga. This beautiful marine mammal, not to be confused with the homonymous European sturgeon, is also known as white whale (the word beluga derives from white, in Russian). It should be remarked that the name is a bit misleading, as the beluga is a toothed cetacean and as such is rather a dolphin than a whale. Like other dolphins, belugas have been introduced in the Black Sea as a consequence of escapes and/or releases from coastal dolphinaria and oceanaria (where animals are kept in near-shore open-air pens which do not adequately prevent escapes of captive animals into the sea - see also a previous article here). The story of the beluga whale in the Black Sea started in the early 1990s, when one individual captured in Sakhalin Bay, Russia, was transferred to Crimea, Ukraine, where it was immediately released, or escaped, into the sea (actually, it was recaptured once, and then soon after released/escaped again). Another beluga was indeed released (or escaped) at the same time and place, and was also observed and reported in the wild several times. The two beluga whales were often observed in the wild near the Turkish, Romanian, Bulgarian and Ukrainian coasts, but their current status is unknown (more details on Birkun 2002; Reeves & Notarbartolo di Sciara 2006).

Interestingly the list of marine mammals spontaneously released in the Black Sea includes also other species, like the grey seal, the northern fur seal, the Steller sea lion, the harbour seal, the Caspian seal and, possibly, some other pinnipeds. Such cases of escape/release have been known in the Black Sea since the early 1980s, but occurred also in other regions. For example, the escape of a sea lion from an aquarium to the wild is also known in the Canary Islands. Otherwise three sea lions escaped from the Prague zoo after the severe flood of 2002, they were all recaptured within a few days, but one of them managed to roam for hundreds of kilometers along the Elbe river from Prague to Dresden, before being recaptured.


Harbour seals at Copenhagen zoo ©  Photo: Vibe Kjaedegaard

The number of animals escaped and/or released in the Black Sea is unknown (but is likely around a few tens), and also the actual fate and impact of the relevant species is uncertain. It is likely that the marine mammals escaped from dolphinaria and similar facilities did never lead to established populations, however it is known that species may have a very long lag phase before getting naturalised, or showing any impact. Of course this does not mean that in the meantime they do not affect the hosting ecosystem. This is especially true in the case of long-living organisms, in which case also a single animal can have a major impact on the ecosystem. For example there is some concern that they could be a source of infections circulating in dolphinaria. In any case such introductions show that the extent of the problem can be unexpectedly large, both in terms of size of animals moved from place to place, and in terms of size of ecosystem affected.

On the other hand, a recent paper by Gladilina & colleagues (2013) highlighted some positive aspect related to the introduction of an exotic grey seal in the Black Sea. The presence of this North Atlantic species has been regularly recorded in the north-east Black Sea since 2001. Its introduction is considered the consequence of an escape from captivity. Surprisingly, no major conflicts have been recorded with fisheries, as fishermen seem to tolerate the presence of this mammal despite the little damage to fishing gears. In any case, the seal seems perfectly adapted to the new environment. This led Gladilina and colleagues to assume that the long term survival of the grey seal in the Black Sea might indicate the possibility of successful re-colonization of the area by monk seals, the only extant aboriginal pinniped in the Black Sea, disappeared at the end of the 20th Century. Hopefully this will be compatible with the growing "novel" community of marine mammals.

February 27, 2013

Always look on the bright side of LIFE!


Up to € 278 million are available to EU Member States for projects under the seventh LIFE+ call for proposals recently published, and also this year invasive alien species (IAS) are explicitly mentioned within the “Indicative list of themes for LIFE+ Nature and Biodiversity projects”. This means that biological invasions are one of the themes for which the European Commission (EC) would welcome receiving proposals to be co-financed. In fact, two headings are particularly suitable for addressing the problems of IAS: Nature and Biodiversity (NAT) and Information and Communication (INF). For example, according to the NAT application brochure:
 Within the classic LIFE+ Nature projects most of the priorities listed in the EU Biodiversity Strategy to 2020 may be effectively addressed: e.g. invasive alien species through control and eradication in and around Natura 2000 sites
LIFE and IAS
The LIFE brochure on IAS


Under the NAT heading, two different strands exist, which are characterized by different requirements and approaches. Under the LIFE+ Nature strand, it is possible to submit projects for the control and eradication of IAS affecting either the Natura 2000 network or species covered by the Habitats and Birds Directives. Site-related conservation measures for combating IAS can be planned both inside Natura 2000 sites (insofar as they are not recurring actions and they directly benefit the species/habitats targeted by the project) and outside Natura 2000 sites. In the latter case, such measures should be carried out  on strategic spots near or adjacent to a Natura 2000 site to improve the conservation status of the species/habitats target, and to limit or prevent damage within the site. In case of species-related conservation actions for combating IAS (that are not site-related), they can be eligible insofar as they directly benefit the species of the Birds and/or Habitats Directives targeted by the project. Some special requirements must be considered in such a case. For example, applicants must provide guarantees and commitments that the investments made will be sustained in the long-term. The explanatory notes of pag.53 of the application brochure provide some additional indications on the requirements for the range of actions that can be envisaged, e.g. prevention of introductions through the prioritisation and management of pathways, establishment of early warning and rapid eradication system, and management of established IAS. The important is to show solid scientific evidence regarding the added value of the foreseen actions for the Natura 2000 sites/network, and to include an awareness raising component, particularly towards stakeholders involved in the introduction of IAS.

In case of projects aiming at tackling IAS not necessarily in respect to the Natura 2000 network, it is possible to consider submit proposals under the LIFE+ Biodiversity strand, in which case they must have a clear innovative/demonstrative character. For this particular strand, the application brochure welcomes 
projects addressing the threats posed by IAS (1) by preventing the introduction of invasive alien species, in particular by tackling pathways of unintentional introduction, (2) by establishing an early warning and rapid response system and (3) by eradicating or controlling established invasive alien species (in line with the dedicated legislative instrument which is currently under preparation, see here). 
Also in this case, the explanatory notes of pag.57 of the application brochure provide some useful clarification. In fact, also such proposals should include an awareness raising component, in particular towards stakeholders involved in the potential introduction of IAS, and should have measurable biodiversity benefits as one of their main outcomes. Besides, the foreseen actions should be targeted towards the achievement of the 2020 Biodiversity Strategy.

It is also possible to present projects dealing with the IAS issue within the INF heading. In relation to this Information and Communication strand, it is worth mentioning that the LIFE+ programme has developed a logical framework useful to design an effective communication campaign, likely to achieve some measurable impact on the environmental problem targeted (e.g. the impact of IAS) and on the level of awareness (about IAS and their threat), by addressing a specific target audience and gaining the support of specific stakeholders, and by monitoring such impact through specific indicators. More details are included in the LIFE+ INF 2013 Application Guide.

February 12, 2013

The invasion of the allergenic ragweed in Europe


The common ragweed is one of the most pollen-allergenic plants and as such represents a serious health risk for humans. Its pollen is a potent trigger of hay fever, rhinoconjunctivitis, and may often cause severe asthma-like symptoms. In Europe the incidence of ragweed allergy ranges widely from 2-50% of the allergic population (roughly ¼ of the European population shows general allergic rhinitis). The impact of common ragweed on human health – affecting mostly children and urban populations (but also horses, dogs and cats) - is not restricted to areas invaded by the plant. In fact, due to transport of ragweed pollen by air masses, allergy reactions are recorded in distances of 100s of km from the site where the plant is situated. Besides, the common ragweed also contains volatile oils that may cause skin irritation and hypersensitivity dermatitis. The associated economic costs are estimated to be around 4.5 billions of euro per year. In addition to this, the ragweed can also have an harmful impact on other sectors, such as agriculture (depending on infestation levels and success of control, yield losses of over 50% are reported). 

A synthetic and systematic review of all available information on the current extent of ragweed infestation in Europe has just been published by the EU within the new comprehensive report “Assessing and controlling the spread and the effects of common ragweed in Europe”.  The study, carried out by an international team of experts led by the Natural Environment Research Council (UK), includes an economic, social and environmental quantification of direct and indirect harmful effects in all sectors, as well as an assessment of measures to control ragweed spread and introduction (now and in future climates). 

Common ragweed (male flowers) ©  Photo: Daniela Bouvet

The common ragweed is actually a native to North America, which has colonised several countries around the world – e.g. Europe, as well as parts of Australia, China, Japan, South America and Taiwan – mostly as a contaminant of agricultural products (including the grain mixtures used as food for birds), machinery or construction materials. In Europe, where it was first introduced in France and Germany in the 1860s, started its spread in the entire region some 20-25 years ago. The result is that large populations of ragweed are now present in the old continent, particularly in Croatia, France, Hungary and Italy, but the distribution range is still expanding as a consequence of changing climate and perhaps adaptation to local climate. Moreover, changes in agricultural land use with large-scale set-aside and abandonment practices, along with an increase of the construction sites and wasteland, are expected to provide new suitable habitats for ragweed. 

The key successful features of this annual herbaceous plant - which can reach a height of over 2 m - are its great adaptability to hostile habitats, its strong ability for re-growth after mowing, and the capability of seeds to remain viable for up to 35 years in soil seed banks. It is most frequently associated with agriculture and is found in cultivated fields (mainly maize, sunflower, leguminous plants) and along irrigation canals. This typical pioneer species is also associated with frequent and extensive disturbance regimes resulting from other human activities (e.g. riverbanks, roadsides, railways, gravel pits, construction sites, waste sites, urban areas, building yards, private gardens and parks).

Common ragweed (leaves) ©  Photo: Daniela Bouvet

The common ragweed is now so widespread in Europe that eradication at this stage of the invasion is no longer feasible. However, it is possible to keep the ragweed under control by every year eliminating emerging plants as far as possible, and preventing or reducing the spread of seeds from infested to non-infested sites. So far, no successful biological control methods have been developed, thus the most effective management measures to control the propagation of this plant are clipping/mowing, uprooting, ploughing, mulching and chemical treatment. Preventive measures include initiatives to limit unintentional spread of ragweed seeds by developing and implementing best practices. In this context, a welltargeted intensive awareness raising campaign is a key to success of both prevention and control strategies (e.g. by reporting observations and making early detection possible). In fact, the EU study has shown some promising future scenario: while in 20 years time the overall impact is expected to slightly increase (about 3%), the implementation of sound management strategies could help reducing such impact by approximately 50%.