Invasive alien species (IAS) threaten livelihoods and biodiversity globally


Invasions from non-native plants, animals and pathogens threaten the economies of the world’s poorest nations, according to a new study.

The study, published in Nature Communications (‘Global threats from invasive alien species in the twenty-first century and national response capacities’) found that one-sixth of the world’s land is highly vulnerable to invasion, including substantial areas in developing countries and global biodiversity hotspots.

Once IAS arrive in a new region, many thrive and outcompete other species, which have adapted to the local ecosystem through evolution. There is a great possibility that IAS can become the dominant force in local environment and out-compete native organisms for resources and habitat, choking river systems and wells, and preventing cattle from grazing and out-competing or eating native species. Around the world, they can cost up to $1.4 trillion annually.

In light of this and how globalization and environmental change are exacerbating the negative impacts of IAS, an international team of researchers analyzed the threats and evaluated national capacities to prevent and manage species invasions.

Often seen as a problem in more developed countries, the new study showed that invasions are also threatening the few remaining biodiversity strongholds in the world’s most fragile economies. They found that many low-income countries stand to lose out as their natural resources are sapped. These negative impacts are only expected to get worse as more trade, cross boarder work and particularly air travel leads to increased biological invasions.

The report highlighted that developing countries also have limited resources or plans to act against invasions of non-native species and are ill-prepared. Their findings also suggest that livelihoods and food security in these fragile economies are likely to be affected.

Poorer economies are crucially reliant on international trade and have little power to regulate imports, so the introduction of highly dangerous species is continuing.

The report’s authors, therefore, call for more international cooperation between governments and NGOs to tackle IAS issues and are encouraging developed countries to share their expertise. By uniting global data, the authors believe we can improve early-warning and eradication schemes to help in the fight against invasive alien species.

CABI at EcoSummit 2016

EcoSummit 2a

CABI promoted its new invasive species initiative at this year’s EcoSummit event which took place in Montpellier, France, from 29 August – 1 September. CABI’s latest initiative aims to tackle the issue of invasive species to improve the lives of 50 million farmers in Africa and Asia.

Launched in Copenhagen in 1996, the event provides a platform for ecological scientists and researchers from around the world to share new knowledge and discuss sustainable solutions to global environmental and ecological challenges. This year’s EcoSummit conference focused on terrestrial ecosystems, especially fragile systems that are less resilient to climate change and the impact that human activities are having on the environment – especially agriculture. The increasing global demand for food was also discussed and how intensified agriculture to meet this demand can adversely affect ecosystems.

CABI’s work on invasive species was highly relevant here as many invasive species cause the loss of natural biodiversity and alter global ecosystems. CABI’s expertise in tackling invasive species in order to promote environmental sustainability, livelihoods and food security is a significant contribution to solving global environmental challenges.

Julien Lamontagne-Godwin was one of CABI’s representatives at the conference. He said: “This conference is vital to showcase the myriad avenues of research in ecology, and is a vital tool to describe and remind us of the importance of a healthy ecosystem for our way of life. Many discussions we had with top scientists here highlighted the value of CABI’s knowledge platforms, such as our Invasive Species Compendium. These conversations also helped us add depth and significance to our new livelihoods initiative on invasive species.”

CABI has been working on invasive species for over 100 years, exploring measures to prevent, mitigate and manage invasive species on a global level. Through a selection of different sustainable techniques such as biological control, CABI tackles some of the worst invasive species that negatively impact terrestrial ecosystems and impact the livelihoods of farmers who depend directly on the ecosystem for their sustenance.

New European Union IAS Regulation


Hydrocotyle ranunculoides

Floating pennywort (Hydrocotyle ranunculoides): on the EU species of Union concern list and a target for biocontrol (Credit: Kate Constantine, CABI)

Invasive alien species are a major threat worldwide, impacting upon millions of livelihoods and threatening biodiversity. The situation is worsening, due in no small part to increased global trade and transport. The economic costs of IAS can be vast: worldwide, invasive species are estimated to cost US$1.4 trillion per year – close to 5% of global GDP.

In the European Union alone, invasive alien species (IAS) are estimated to cost €12-20 billion a year.

In response to this threat, the European Union adopted Regulation (EU) No 1143/2014 which makes compulsory the management of key IAS that are of concern to the region. Methods include limitation of spread, eradication of early invasions and active management of established IAS. A list of 37 species to be included under the regulation was approved by EU Member States in December 2015 and has recently come into force (Regulation (EU) 2016/1141). It includes 23 animals and 14 plants whose current and potential impacts across the region will mean that collaborative and concerted action is required across the EU.

This is part of the EU’s biodiversity strategy which aims to halt the loss of biodiversity and ecosystem services in the EU by 2020 and is in line with the Convention on Biological Diversity’s (CBD) Aichi Targets, particularly Target 9:

“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 CABI, we have been working on invasive species at a global scale for decades and are experts in their management using both traditional methods and through biological control. This new legislation is welcome; recognising the serious threats that invasive species pose and imposing compulsory measures to lessen the spread and impacts of IAS in the EU.

Invasive species: A global threat to trade and livelihoods


Copyright: CABI. Credit: Sven Torfinn, Panos Pictures


A new report supports the fact that invasive species have the potential to undermine global food security and sustainable development, a vital statement supported by Goal 15 of the Sustainable Development Goals which states that we need to: introduce measures to prevent the introduction and significantly reduce the impact of invasive alien species on land and water ecosystems and control or eradicate the priority species.

Invasive species are a plants, fungi or animals that are not native to a specific location (an introduced species) which spread and can cause damage to the environment, human economy or human health. If not managed sustainably, these invasive species often negatively impact natural biodiversity and ecosystems, and consequently, farmers’ livelihoods.

Rapid globalization and increased trade is compounding this problem. As agricultural and non-agricultural products move from one country to another, the risk of introducing invasive species to non-native regions is also increased.

Research carried out by Dean Paini (senior research scientist – CSIRO) on the Global threat to agriculture from invasive species was carried out across 124 countries. He found that 40 of the countries in the study had the possibility of being invaded by at least one of the 1,297 invasive pests reviewed. The research identified a correlation between the type of crops grown in a country, the level of trade with other countries and invasive pests present in trading countries. He reported that China and USA were the greatest potential sources of invasives species due to the scale of their agricultural production and high levels of trade with other countries.

The report found that countries in sub-Saharan Africa were more vulnerable to the impacts of invasive species. This is because of their less resilient farming systems and increased reliance on the natural ecosystem. Impacts of invasive species are mostly experienced by rural farmers but it’s also felt at the national economic level as agriculture contributes significantly to their Gross Domestic Product (GDP). It is therefore pertinent to understand the source, nature and method of spread of invasive species so that they can be prevented, mitigated or managed – if they’re already established.

We at CABI have launched a global initiative to raise awareness of the global threat of invasive species on food security, trade, sustainable development and rural livelihoods – see our dedicated website. CABI has over 100 years of scientific expertise and knowledge on invasive species and we are using this knowledge to help tackle the worst invasive species across Africa, Asia and Latin America. For instance, Opuntia stricta – an invasive cactus – has colonized vast grazing areas in Kenya, resulting in minimized grazing land and the death of livestock. We have therefore used our scientific expertise to help address this invasive by introducing a sap-sucking bug (Dactylopius opuntiae) which is known to feed only on Opuntia stricta without causing harm to any other native plant species. This bug has previously been successful in controlling Opuntia stricta in South Africa and has already started being effective in addressing the same issues in Kenya.

As sustainable agriculture and rural development is at the core of our work, we aim to tackle invasive species by improving the knowledge of local people on the different methods of preventing the arrival and spread of invasive species. We also want to support agencies responsible for early detection and eradication of invasive species as well as mitigate invasive species through sustainable measures. This will ensure that invasive species are addressed without causing further harm to the environment and livelihoods.

Tackling invasive species to protect farmer incomes and livelihoods

Elias Kamuga“I have suffered [crop] losses amounting to 90%. I have no other source of income apart from tomato farming. I was relying on this crop to feed my family. I have nothing to do now other than try to think of what to do next.”

Elias Kamuga, Farmer, Kenya

Elias is a smallholder farmer from Kenya. Every year he sells his tomato crop at the local market, which gives him enough money to feed his family. But the arrival of a tomato pest to his region in Kenya has stopped that. The pest – a moth called a tomato leaf miner or Tuta absoluta – was recently introduced to Africa. This pest is an invasive species, and is destroying people’s livelihoods.

In 2015, Elias started to notice his tomatoes were being damaged by this pest. He tried taking them to market, but customers said they had too many holes and spots and were no good. He could not sell his produce. He believes he lost 90% of his tomato crop to the pest, and had no other source of income. Elias tried fighting this tomato pest with chemicals but they did not work. Elias now has to find another way to earn money. Thousands of farmers are in his position.

Invasive species, like Tuta absoluta, are devastating livelihoods. Tomatoes are one of the most widely cultivated crops in sub-Saharan Africa, grown in the backyards of almost every home. This important cash crop and source of nutrition is now being threatened by the recent arrival of the pest.

Tuta absoluta is rapidly moving across the African continent, decimating crops in Egypt, Ethiopia, Kenya and Tanzania. It has recently reached Nigeria, where a state of emergency has been declared – the pest has destroyed an estimated US$5.1 million of tomatoes and forced at least one major tomato processing plant to close. Growers do not know how to control it and many have abandoned tomato farming altogether. The race is on to prevent its spread with management schemes planned to limit its devastation.

Since 2014, CABI helped governments in Africa halt the Tuta absoluta threat and continues to do so. We are currently helping countries like Burundi, Kenya, Nigeria and Tanzania understand how they can best prepare prior to a pest invasion and are delivering practical knowledge on how to manage the pest once it has arrived. To address the recent severe outbreak in Kaduna State, Nigeria, we have provided the government with a technical brief on the tomato leaf miner together with available management experiences to help them develop a control strategy.

In 2015, we launched an important initiative to raise awareness of the threat of invasive species to the livelihoods of the rural poor. Our aim is to draw partners together from around the world to bring pest management solutions that exist already to the people who need them. We included Tuta absoluta as one of the priority targets for coordinated management. Our goal is to protect rural communities in developing countries from the devastating impacts of specific invasive species.

See Elias’ story.

The three Cs of the Invasives’ programme development: concepts, compromise and coffee

Since March 2016, I have been working as the programme support manager for the multi-sectorial development initiative called the Invasives programme. Our new Invasives initiative will be undertaking regional, national and local technical and partnership activities to deal with some of the worst biological invasions that are threatening livelihoods in poor rural areas. As we look to leverage the successful Plantwise initiative (, the Invasives programme team is looking to build additional partnerships in the private, public and civil society sectors. Needless to say, from a personal point of view, it has been a steep learning curve!

But it has been productive! In 3 months, we have managed to finalise the strategy (the first version of it anyway), develop a logical framework, partnership and budget documents, a theory of change, and link our activities to CABI’s global gender strategy and monitoring and evaluation process.

How did we achieve this, all in time for the CABI review conference in July? Through the excellent combination of concepts, compromise and coffee

Let me explain.


You cannot develop a multi sectorial global programme without a strong conceptual basis.

The Invasives programme definitely has strong roots: as an organisation, CABI has over 100 years of experience dealing with problems species in agriculture around the world, notwithstanding staff’s academic and practitioner knowledge is immense working on projects throughout the globe. This experience is underpinned by a world leading invasive species information database: the Invasive Species Compendium ( What is more, the programme’s goals are complementary with CABI’s largest programme to date, the prize winning Plantwise initiative. Indeed, our partnerships with local partners as well as the analysis of plant clinic information will be crucial for the development of timely invasive species integrated pest management interventions in local areas. The approach at a regional level means we can deal with cross border issues, whilst our locally focused activities means helping vulnerable groups out of poverty through job creation and/or better agricultural yields. The core team developing the programme, the technical management teams, composed of 8 senior staff, headed by Dr Sean Murphy, have been given the responsibility of developing the programme’s work packages. Their intimate knowledge of invasive species and international development will be invaluable for the smooth running of the programme in its infancy.


Whilst our experience and knowledge on the Invasive species theme is definitely an advantage, it also means CABI contains some opposing views on how to achieve the programme’s goals. Hence the second “c”: compromise

As a programme manager, the role is principally to keep the programme moving forward. This inevitably means you will have to manage conflict between ideologies. For example, the programme from a marketing or commercial sense might stray far from what a research professional might see as a successful programme. A donor-focused professional will want to see different aims than a development profession working in the field. Indeed, it is the programme manager’s role to listen, analyse and suggest compromises. A degree in psychology would be helpful, let alone one in ecological economics, social dynamics or conservation agriculture (luckily I have one of those!). A programme manager’s role, while content driven, will most likely earn his/her corn by his ability to diplomatically find a solution and move forwards.


It is somewhat ironic that a programme manager’s staple drink is one of the key crops in conservation agriculture and commodities. Indeed, coffee is one of the sole (soul?) constants in a complex management role. Do you think I am overstating it? Try the 3 day workshops to hash out logical frameworks with technical teams, tight deadlines to learn about, and draft, a programme theory of change, organising milestones, integrating gender and monitoring and evaluation strategies, fixing and predicting budgets and partnerships… Oh yes, add a new-born child and the business end of a PhD in the mix, and you can understand why coffee has become a pretty important part of my life!

The programme is in good shape, with strong endorsements from all sides. The programme strategy will be out very soon. That is enough of a reward for now.

That is, until we roll out the initiative and help 50 million farmers improve their livelihoods.

A fifth of the world’s plants under threat, as report says 391,000 species now known to science

Dave Simpson – 11 May 2016

A ground-breaking report from the Royal Botanic Gardens, Kew, has produced an estimate of the number of plants known to science. By searching through existing databases, the researchers have estimated that there are now 390,900 known plant species, of which around 369,400 are flowering plants. But this figure is only those species currently documented: new species are being discovered all the time, including over 2000 in 2015 alone. But more worryingly, it is suggested that 21% of plant species are under threat, from a range of pressures including climate change, habitat loss and invasive species. The invasive species component of the report, which draws heavily on CABI’s Invasive Species Compendium, says that nearly 5,000 plant species are documented as invasive, from over 13,000 vascular plant species naturalised outside their native range.

Prof Kathy Willis, director of science at RBG Kew, said: “It’s really important to know how many plant species there are, where they are and the relationship between the groups, because plants are absolutely fundamental to our well-being”

And on invasive species, the head of conservation science at Kew, Dr Colin Clubbe, said that invasive species are one of the biggest challenges for biodiversity. Quantifying the number of species regarded as invasive is a key step towards addressing the problem. “Now that we’ve got this list and this number, it’s certainly a bit like know your enemy,” said Dr Clubbe.


Japanese knotweed, a major invasive
“We know what we are dealing with, we can then look at them, and see what’s similar, what makes a good invasive, and then see how we can use that information to have better management practices in place or recommendations for how you deal with them.”

Trade, plant collecting, and movement of people, has led to at least 13,168 species of vascular plants becoming naturalised outside their native range. The report says that they become classed as invasives once they start to compete with native vegetation and spread to a degree that causes damage to the environment, the human economy or human health. The effects on livelihoods, and on ecosystem services such as agriculture, forestry, water and pollinators, can be staggering: the Kew report cites one study as estimating the total costs from all invasive species as nearly 5% of the world economy, and it also quotes CABI research which estimated the impact on the British economy alone as around £1.7 billion every year. Japanese knotweed, one of the most invasive plants in the UK, costs Great Britain over £165 million annually to control.

The Kew report synthesizes invasive species data from the open-access CABI Invasive Species Compendium, the Global Invasive Species Database (GISD), global reviews of invasive trees and shrubs by Rejmánek and Richardson, and Weber’s Invasive Plant Species of the World: a Reference Guide to Environmental Weeds published by CABI in 2003. CABI’s ISC – flagged in the report as “the most comprehensive web-based resource” – has datasheets for 4,841 of the total of 4979 invasive vascular plants in Kew’s consolidated list.

Identifying other threats to plant biodiversity, the report says that farming is the biggest extinction threat, representing 31% of total risk to plants. Logging and the gathering of plants from the wild is responsible for 21.3% of the risk, followed by construction work with 12.8%. The report said that some 1,771 areas of the world have been identified as “important plant areas” but very few have conservation protection measures in place.

Highlighting just how many plant species are already important to humans, the report says that some 17,810 plant species have a medical use, 5,538 are eaten, 3,649 become animal feed and 1,621 are used for fuels. Over 11,000 plant species are used for materials, for example fibres and timber.

“[Plants] provide us with our food, our fuel, our medicines – even controlling our climate” says Professor Willis.

The report can be downloaded in full, or data from individual sections accessed, at the website A symposium on the report is being held at Kew on 11-12 May. Moving forward, the global assessment will now be carried out annually, allowing scientists to monitor how plants are changing over time.