The western Africa region supports a significant proportion of the world’s species dependent upon freshwater wetland habitats. Given that the region represents approximately 5% of total global land mass (excluding Antarctica), it is apparent that many groups, waterbirds, plants and mammals in particular, are well represented within the region.
Number of described species
Number of species in western Africa
% of global total found in western Africa
Data sources: Balian et al. (2008); IUCN Red List (2008)
Of the 1,435 species assessed here at the regional scale, just over 14% are regionally threatened. When compared with the global level of threat to some of those taxonomic groups that have been comprehensively assessed (e.g. amphibians, 30% threatened; birds, 12% threatened; mammals, 21% threatened (IUCN 2008)) this figure may seem relatively low. This can largely be attributed to the relatively low levels of past development and subsequent impacts to western Africa’s environment as compared to some other regions of the world. The Mean Species Abundance (MSA), an index of the mean abundance of original species, in sub-Saharan Africa in 2000 was calculated to be 73%, whereas Europe (MSA of 45%) and South and East Asia (MSA of 55%) are much lower . There are, however, a number of serious current and looming threats to the region’s inland water ecosystems with massive levels of population growth and development. This, combined with the predicted impacts of climate change, sets the stage for a potential major loss of freshwater biodiversity. The MSA predictions for 2050 are that sub-Saharan Africa will have the greatest decline in MSA of any region on Earth with a decline of 11.7%, compared to a global decline of 7.6%.
A comparison can also be made with other comprehensive regional freshwater biodiversity assessments. Eastern Africa, an area very rich in freshwater dependent species and very high levels of endemism, has just under 23% of species assessed as regionally threatened (note: this doesn’t include plants) – a level of threat significantly higher than that observed in western Africa. The eastern Africa situation was largely attributed to alien invasive species impacting on the many range restricted endemic fish species of the large lakes, and high levels of wetland degradation. For southern Africa, just over 7% of the species are assessed as regionally threatened. This relative low level of threat is most likely a reflection of the current low levels of development throughout much of the region, with the exception being South Africa, where development levels are much higher, and where the majority of the threatened species in the region are currently found.
IUCN Red List Categories: EX - Extinct, EW - Extinct in the Wild, CR - Critically Endangered, EN - Endangered, VU - Vulnerable, NT - Near Threatened, LC - Least Concern, DD - Data Deficient
Many species (34.5%) are endemic to the region, so their regional Red List assessments are equivalent to global assessments and therefore represent the risk of global extinction for the species. Of the 496 regionally endemic species assessed here (fishes, molluscs, odonates, crabs and plants), 170 species (34.3% of those assessed) are globally threatened.
With the inclusion of Red List assessments for a number of additional taxonomic groups assessed through other initiatives, the number of species assessed for their global risk of extinction in western Africa is 844, of which 203 species (24% of those assessed) are assessed as globally threatened (below), which is twice as high as in southern Africa which has a threat level of 12% when the same taxonomic groups are included.
IUCN Red List Categories: EX - Extinct, RE - Regionally Extinct, EW - Extinct in the Wild, CR - Critically Endangered, EN - Endangered, VU - Vulnerable, NT - Near Threatened, LC - Least Concern, DD - Data Deficient.
Additional data sources: Waterbirds - Wetlands International, Amphibians - IUCN Global Amphibian Assessment, Turtles - Peter Paul Van Dijk, Mammals - IUCN Global Mammal Assessment.