Almost a Third of Tropical Africa’s Flora Faces Extinction

Our new study reveals that 31.7% of tropical Africa’s vascular plant species could be threatened with extinction and published in the journal Science Advances on 20 November 2019. Using a new approach based on the key elements of the assessment process used by the International Union for Conservation of Nature (IUCN), we have been able to assess the potential conservation status of tropical flora on the scale of a continent.

Stévart, T., Dauby, G., Lowry, P.P., Blach-Overgaard, A., Droissart, V., Harris, D.J., Mackinder, B.A., Schatz, G.E., Sonké, B., Sosef, M.S.M., Svenning, J.-C., Wieringa, J.J., Couvreur, T.L.P., 2019. A third of the tropical African flora is potentially threatened with extinction. Science Advances 5, eaax9444.

https://advances.sciencemag.org/content/5/11/eaax9444 [open access]

Given the anthropological and climate threats facing nature, the conservation of tropical biodiversity is a major challenge. To encourage the implementation of better biodiversity management practices, countries and international agreements on biodiversity refer to the assessments of species “at risk of extinction” performed by the IUCN as part of a standardised procedure (See Red List of Threatened Species). This approach remains the most comprehensive and objective means of identifying species in need of protection.
 
However, while the conservation status of the majority of vertebrate species has been assessed, the same cannot be said for plants, although they are critical to earth ecosystems. This is especially true in tropical regions where the flora is very diverse but remains poorly documented.
 
6,990 Potentially Threatened Species
 
In this study, we developed a new fast and automatic approach based on key elements of the conservation assessment process used by the IUCN. Their objective was to provide relevant information on the conservation status of a large number of plant species at broad scales, in the form of Preliminary Automated Conservation Assessments (PACA).
 
We then applied this methodology to the RAINBIO database, which contains over 600,000 georeferenced occurrences of plants in tropical Africa across more than 20,000 vascular plant species.

After classifying these species into six categories – which include species that are “probably or potentially threatened”, those that are “potentially rare” and those that are “potentially not threatened” – we reveal that almost a third (31.7%) of the 22,036 vascular plant species studied are potentially threatened with extinction, and an additional 33.2% are potentially rare (they could be threatened in the near future).
 
Facilitating Large-Scale Biodiversity Assessments
 
After determining the most endangered species, we also identified four regions in Africa that are particularly exposed: Ethiopia, central Tanzania, the south of the Democratic Republic of the Congo and the West African tropical rainforests.
 
We highlight the advantages of this approach, based on the preliminary automated conservation assessments, in terms of cost reduction, time saving and the potential to carry out large-scale assessments.