Restoring degraded drylands in Africa for improved water security

Drylands are severely challenged by interlinked land degradation, climate change, and biodiversity loss crises, negatively impacting the livelihoods and well-being of millions of people. Halting land degradation and restoring degraded lands is critical to address these interlinked crises and enhance human well-being. The restoration of degraded ecosystems is a global priority, as reflected by the growing number of restoration initiatives such as the UN Decade on Ecosystem Restoration (2021-30) and the Bonn Challenge. Governments worldwide have committed to restoring hundreds of millions of hectares of degraded land under these and related initiatives. In Africa, in particular, the African Forest Landscape Restoration Initiative (AFR100) aims to bring 100 million hectares of land into restoration by 2030. Achieving this ambitious target implies restoring drylands.

Restoration interventions should aim to restore multiple functions and generate a range of ecosystem services that benefit multiple stakeholder groups, from the local to the global level. Unfortunately, many restoration attempts in drylands have failed to do this, compromising water security, biodiversity, and local livelihoods. Ensuring water security is of critical importance in the context of drylands. My research focuses on improving understanding of the impacts of dryland restoration on water security, particularly through the restoration of soil health and soil hydrologic function.

In this lecture, I will review my past work on the impact of tree-based restoration on soil hydrologic function and water availability in agroforestry systems and forests and on the main determinants of soil hydrologic function across sub-Saharan Africa. While findings from this work indicate considerable potential to improve soil hydrological function and water security through land management and restoration practices, substantial knowledge gaps remain. I will highlight critical gaps and explain how my ongoing research aims to fill some of these gaps and contribute to providing the evidence to guide sustainable land management practices and restoration interventions for improved land health and water security across drylands in Africa.