The researchers say the burden for Nigeria, the most populous country in Africa, is about $ 1 billion a year. They have losses of $ 317 billion for the Democratic Republic of the Congo, $ 248 billion for Niger and $ 229 billion for South Africa.
Data on invasive alien species, or IAS, in Africa are scarce, and obtaining the material for the study was ‘challenging’, said Dr. Eschen said. Therefore, in some cases, researchers have relied on estimates.
For example, weed costs were based on farming areas in each country and the average wages for farm hands. The authors used publicly available data from organizations such as the International Union for Conservation of Nature and the United Nations Food and Agriculture Organization. It was supplemented by a survey of 110 agricultural experts from 30 African countries.
For countries with insufficient data, they used numbers from areas with similar climates. Western Sahara, Djibouti and Equatorial Guinea have been left out altogether.
The study’s estimates for labor represent opportunity costs more than actual wages, the authors said. Small-scale farming and weeding, for example, are often done by women and children, and that labor is usually not paid. “If people do not have to weed IAS, they can do something else, such as going to school or undertaking an income-generating economic activity,” said Dr. Eschen said. “Although the estimate does not reflect the salaries paid, it is an indication of the effort required to deal with these species.”
Dr. Eschen said governments should be proactive in halting the losses.
“Investments to find more effective ways to tackle IAS – including preventing the spread of new and established species – as well as cost-effective management of widespread species using, for example, biological control, can reduce management costs and yield losses,” he said. he said.