By Rootooba Contributor , May 20, 2021
CABI scientists have conducted the first comprehensive study on the economic impact of a range of Invasive Alien Species (IAS) on Africa’s agricultural sector, which they estimated to be USD $3.6 trillion a year.
This is equivalent to 1.5 times the Gross Domestic Product (GDP) of all African countries combined – or similar to that of Germany.
The average annual cost of IAS per country was USD $76.32 billion. Full details of the cost for individual countries are outlined in the paper published in the journal CABI Agriculture and Bioscience.
The team, comprising scientists from CABI centres in Africa and Europe, conducted a thorough literature review and online survey of 110 respondents – largely working in government or research – and established that Tuta (Phthorimaea) absoluta caused the highest annual yield losses at USD $11.45 billion, followed by the fall armyworm (Spodoptera frugiperda) at USD $9.4 billion.
The research took account of yield losses of major crops including maize, tomato, cassava, mango and banana (USD $82.2 billion), as well as labour costs – through weeding (USD $3.63 trillion) – and loss of income derived from livestock (USD $173 million).
The annual impact of IAS – that also included Prostephanus truncatus, Bactrocera dorsalis and Banana bunchy top virus (BBTV) – was highest on cassava (USD $21.8 billion), followed by citrus fruits (USD $14.6 billion), tomato (USD $10.1 billion), maize (USD $9.8 billion) and banana (USD $7.1 billion).
Lead author Dr René Eschen said, “This study reveals the extent and scale of the economic impacts of Invasive Alien Species in the agricultural sector in one of the least studied continents.
“The results highlight the need for measures that prevent new species from arriving and established species from spreading, and that reduce management costs for widely present and impactful species through methods such as biocontrol.This will potentially reduce future production costs, lower yield losses and improve the livelihoods of farmers and other affected land users.”
Co-author, Dr Bryony Taylor, said, “We have added to the knowledge base of the costs of Invasive Alien Species to Africa’s agricultural sector by including all countries within the continent where previous research only included a few.
“We also include the cost of reduced livestock-derived income and research and labour costs, which are generally not included in estimates of the costs of Invasive Alien Species.
“The results of this study provide policy makers with the evidence needed to enable prioritisation of management measures for IAS, thereby reducing costs in the long term.”
Fernadis Makale, another co-author on the paper, said, “The large estimate for the weeding costs may come as a surprise but this work, often carried out by women and children, is never measured as part of the African economy.
“Moreover, it should not be concluded that people are being paid that amount as salaries. Rather, the estimate represents an opportunity cost, meaning that if people didn’t need to weed IAS could do something else, such as going to school or undertaking an income generating economic activity.
“In addition, our study provides evidence of the need for country and regional quarantine and phytosanitary measures to prevent the entry and spread of new IAS, preventing additional, potentially huge costs as new IAS spread across the continent.”
The study comes after a policy summit on Invasive Species held in 2019, where 70 delegates, representing policymakers, research, the private sector and civil society from across Africa, resolved to develop a strategy and action plan to fight against Invasive Alien Species.
In response to the findings, Dr Dennis Rangi, Director General, Development, CABI, said, “An estimated USD $3.6 trillion a year impact of Invasive Alien Species on Africa’s agricultural sector is a tremendous loss where over 80% of people living in rural areas rely on the crops they grow for food and income.
“The long term effects are exacerbated by COVID-19 which continues to apply intense pressure on an already fragile agricultural sector and food supply chain. Notably, Governments across the continent put in place mitigation measures to manage the pandemic and its impact. Kenya for example proposed a USD $503 million economic stimulus package in 2020 to cushion its citizens.
“This is the same resolve, urgency and investment our Governments need to channel towards managing the Invasive Alien Species problem.
“Under the African Union’s stewardship, countries now have a Strategy for Managing Invasive Species in Africa. The 2021-2030 strategy provides a framework for all relevant stakeholders at the Continental, Regional and National level can use to sustainably prevent and eradicate invasive species in Africa.” He concludes.
