1In the late 18^th and early 19^th century, the rapid growth of steam navigation had an unexpected impact in the form of a plague pandemic. Within 10 years, the black rats transported in the holds of ships carried the disease to all the major ports of the world. This historical example is one of the consequences of a biological invasion. There are other possible effects, notably on biodiversity, agriculture and the economy.

Catching rats, Cotonou, Benin.

2Despite the signing of international conventions aimed at preventing the spread of invasive species, the countries of the Global South are often ill-prepared for the risks and challenges posed by these bio-invasions. In sub-Saharan Africa, not all invasive species are known, and inventory initiatives are few and far between. Aware of the situation, researchers launched a number of initiatives in conjunction with several universities in Senegal, Niger and Benin. In 2016, a team of scientists from these three countries was established, laying the foundations for the implementation of a wider network in 2018: an international research group – Global South (GDRI-Sud) aimed at supporting research and training in invasive species in West Africa, and raising awareness of the challenges they pose among African teachers, public authorities and socio-economic stakeholders.

Port of Cotonou, Benin.

3For example, researchers are currently establishing a partnership with the port of Cotonou to test various innovative approaches intended to better control invasive species, including the rodents likely to be introduced via merchant ships. In this port alone, one tenth of the amount of rice passing through storage warehouses is lost because of exotic mice and rats. And this is just a very small part of the actual cost of bio-invasions, as the cost associated with their consequences in terms of health, agriculture and ecosystem services remains completely unknown. As an order of magnitude, the USA allocates USD 128 billion a year to the monitoring and control of invasive species, i.e. 1% of its GDP.