Opinion: Invasive species — the hidden threat to sustainable development

Devastating damage to maize crops caused by fall armyworm in Ghana. Photo by: CABI

In laying out the Sustainable Development Goals, the international community set itself an ambitious set of targets to achieve by the end of the next decade. But the challenge of realizing the 17 SDGs means that development organizations often only focus on supporting the operationalizing of a particular subset of the goals. If you’re focused on poverty, health or water, why should you care about a few bugs or weeds cropping up where they shouldn’t?

The reality is that millions of the world's most vulnerable people face problems with invasive weeds, insects, plant diseases, and animals, which are out of control and have major economic, social, and environmental impact. 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.

These staggering losses are mostly due to reduced agricultural productivity — i.e. higher management costs to control outbreaks and lower yields due to crop losses. Due to their higher reliance on the agricultural sector, this naturally affects the economic performance of low- and middle-income countries disproportionately. But the threat posed by invasive species is not limited to agriculture.

Higher production costs and reduced yields lead to lower incomes and increase poverty [SDG 1: Elimination of extreme poverty].

Yield losses to invasive species such as tuta absoluta, fall armyworm or parthenium have been known to reduce crop yields by over 90 percent, with devastating results for smallholder farmers who rely on their farms for income.

“In East Africa, five major invasive species alone cause $1 billion in economic losses to smallholder farmers each year.”

— Roger Day, program executive, CABI

Reduced crop yields and higher food prices have a direct impact on food security [SDG 2: Achieving zero hunger].

Staples such as maize and rice are severely threatened by the spread of the fall armyworm. In Nigeria, the 2016 outbreak of tuta absoluta made tomatoes — a nutritional staple — unaffordable for most of the population.

Invasive species cause a variety of health problems [SDG 3: Ensuring healthy lives].

Parthenium can cause respiratory problems and dermatitis in humans. Floating mats of water hyacinth are a habitat for mosquitoes, contributing to the spread of mosquito-borne diseases.

Masai boy surrounded by the invasive cactus Opuntia Stricta in Laikipia, Kenya. Photo by: CABI

Children and women are disproportionately affected by invasive species [SDG 4 and SDG 5: Achieving inclusive and equitable quality education and gender equality].

Weeding is still done by hand in many countries and it is often the work of the women and children. This has an impact on children’s education if they are made to spend less time in school in order to work in the fields. It also perpetuates gender inequalities given that women working in the fields are then further exposure to the health problems such work can bring.

Invasive species reduce water quality and impact aquatic biodiversity [SDG 6 and SDG 14: Providing access to clean water and conserving oceans].

Aquatic weeds such as water hyacinth, salvinia molesta, and pistia stratiotes disturb freshwater systems, block waterways, and diminish fish stocks by reducing water quality. In arid regions, the roots of prosopis go so deep that they disrupt the water supply needed by households, agriculture, and industry.

The Centre for Agriculture and Biosciences International has been working on tackling invasive species for over 100 years, and are leading the way in the response to this global issue. CABI is about to launch a new program, Action on Invasives, which will assemble a coalition of stakeholders to adopt a systems-based approach to tackling invasive species across regions and economic sectors. By embedding this best-practice framework, CABI hopes to empower low- to middle-income countries to be able to defend against invasive species, detect them if they do break through, and ultimately defeat them.

Invasive species block infrastructure, impact trade, and lead to reduced employment opportunities [SDG 8 and SDG 9: Ensuring work and economic growth and building resilient industry, innovation, and infrastructure].

Reduced yields have an impact along the value chain, with fewer jobs both in the field and in post-harvest processing. Serious infestations stop rural communities from accessing market and services, choke irrigation canals, and hydroelectric schemes, or make an area less attractive to tourists. The presence of invasive pests and diseases is a barrier to overseas trade due to quarantine regulations. Some countries have already banned the import of mangoes and bananas from Africa due to the fruit fly bactrocera dorsalis.

Invasive species impact the environment and biodiversity [SDG 13 and SDG 15: Combat climate change and manage forests and desertification].

Invasive species contribute to desertification and reduce the resilience of vulnerable communities and natural habitats to the effects of climate change. They are the second greatest threat to biodiversity after habitat loss, and can reduce native plant richness by up to 90 percent.

While this catalogue of disruptions may seem daunting, there is a reasonably straightforward three-pronged approach to address the problem.

1. Prevention: Developing and implementing biosecurity policies to prevent the arrival and spread of invasive species, and raising awareness of potential threats at the local level. For example, national and state biosecurity agencies in Australia have an impressive track record of implementing comprehensive quarantine and containment procedures, with the active support and involvement of farming communities. This helped limit the spread of the devastating banana fungus Panama disease TR4 when it appeared in Queensland in 2016.

2. Early detection and rapid response: Building capacity to develop and implement surveillance and emergency action plans for detecting and eradicating new invasions. Two years ago in Sri Lanka, the invasive banana skipper was identified early enough by plant doctors on the Centre for Agriculture and Biosciences International’s Plantwise program for national plant protection agencies to intervene and limit the spread. This saved millions of dollars in potential losses for Sri Lanka’s banana industry. The early detection was only possible because the plant doctors were equipped with tablet computers, allowing them to tap into a global network of diagnostic experts.

3. Control: Scaling up existing invasive species management solutions and making sure that those living in rural communities have access to best practice and locally adapted solutions and are actively engaged in running them. While control methods vary from species to species, development and use of biological controls — the controlling of pests by introducing natural enemies — is far lower in developing countries. Considerable investment into research and development is required, but it poses a real opportunity for local companies to take the lead and reap the benefits. Governments and civil society organizations involved in community education could also begin including existing information on invasive species in their training materials.

This framework requires commitment across sectors and borders, at both the micro and macro levels. Just as neighboring farmers need to work together to ensure a pest doesn’t cross from one plot to the next, so too do countries need to act together. It also needs to be accepted across the public and private sectors.

We should remember that the solution is already embedded into the goals themselves. SDG 17 on partnerships explicitly requires organizations to change from working in a silo approach to working instead in collaboration across sectors. Incorporating biosecurity and invasive species management considerations into your development work could have a major impact in mitigating invasive species’ threat to sustainable development. To tackle this hidden threat we have to take joint responsibility: Scientists such as myself need to raise awareness and become actively engaged in sustainable development, while development organizations have to reach out to local and global experts to ensure their activities don’t exacerbate the problem.

To find out more about CABI’s new Action on Invasives program and how your work can limit the impact of invasive species, click here.

About the author

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    Roger Day

    Roger Day is the program executive for CABI’s new Action on Invasives program. With 25 years' experience of working in tropical agriculture in Africa and Asia covering research, development, and capacity building, he has a broad knowledge of agricultural development issues in invasive species, commodity crops, and knowledge for development. His specialist areas of expertise include biological control, phytosanitary systems and standards, integrated pest management, and entomology.

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