Wetlands help maintain wetland and dryland biodiversity in the Sahel, but that role is under threat: an example from 80 years of changes at Lake Tabalak in Niger

Abstract

Wetlands in arid and semi-arid regions are enormously important for the biodiversity of the surrounding drylands, and for the humans living there. Increasing human populations put increasing pressure on the dryland resources as well as on those wetlands. This case study of Lake Tabalak in Niger shows the changes that have taken place there over 80 years. From a tree-covered depression with a traditional well, it changed to a 1.150 ha lake in the 1970s. From this lake, where pastoralists and their livestock had free access to water and fodder all year round, it developed into a depression with almost wall-to-wall market gardens. In April–June, the end of the dry season, herders now have to pay large sums to have their animals feed on what there is of crop residues at the lake, before continuing to the natural grasslands further north once the rains have arrived. What little is left of the teeming wildlife in that region around 1940 is not coming to the lake anymore. The lake’s usefulness for trans-Saharan migratory birds has demonstrably decreased over the past 20 years. This lake, a key component in the dryland system it belongs to, facilitating year-round use of the drylands that surround it and connecting dry season grazing areas in the south to rainy season grasslands in the north, has become, or is becoming, degraded for all uses, not least wetland and dryland biodiversity. Increasing pressures over the coming decades will cause similar dryland systems elsewhere to suffer the same fate and lose important parts of their functionality and their biodiversity, if adequate countermeasures are not taken. Such countermeasures must concern the wetland systems rather than the individual wetlands that the dryland systems contain, and lead to participative integrated natural resource management involving all stakeholders, for instance through multi-stakeholder fora.