Nature-based solutions (NbS) are actions to protect, sustainably manage and restore natural and modified ecosystems in ways that address societal challenges to provide both human well-being and biodiversity benefits. Thus, to be effective, NbS developed for biodiversity conservation and water resource management must cater for both the ecological and socioeconomic aspects of a landscape. The Ewaso Ng’iro basin in Kenya is a rich ecosystem that provides many ecological, social and economic benefits for the local communities. Unfortunately, population growth, land use change, changing consumption patterns, among other reasons, threaten the ecosystems and the communities’ livelihoods. These challenges are exacerbated by climate change. This creates a unique opportunity for NbS interventions to be used to conserve biodiversity and address water scarcity.
The ongoing semi-circular bunds incubator in the Naibunga Community Conservancy, in Laikipia County —jointly implemented by the Wyss Academy, JustDiggit, and community group Green Earth Warriors—is one such intervention. In a year since digging of the now 32,000 bunds, early monitoring results suggest that there has been improvement in vegetation cover (primarily grass), and alternative livelihoods are being explored.
In 2023, soil sensors were installed to monitor the impact of semi-circular bunds on soil moisture and temperature, and preliminary results show that bunds—compared to the control site—tend to retain water longer, meaning there is a higher chance that the bunds could support plant growth. Further, soil sensors indicate that when the bunds fill with both rainwater and water flowing at the surface, there is time for water to infiltrate and percolate through the soil layers, which increases soil water content. Whether aquifers are recharged is still an open question. With this positive outcome on the surface, the Interdisciplinary Research team on Water Scarcity (ID Water Scarcity) is additionally focused on the groundwater situation. This proves tricky, seeing as groundwater is, quite literally, in the ground and unseen. The best course of action then is modelling, which requires data. In collaboration with South Eastern Kenya University, the team is in the process of collecting this data by measuring water levels in existing boreholes. This will build a baseline for modelling groundwater levels in the Ewaso Ng’iro basin.
Restoration projects like the bunds help plant species grow, subsequently creating habitats for diverse animal species. The process of restoration also helps creatures move back into an area, which is sped up by the creation of new microhabitats such as temporary pools in the water bunds, growing grasslands resulting from the reseeding efforts, and an environment with improved soil health. These are all indicators that the ecosystem is healthy. Plants are also very important for hydrological processes like capturing water and managing evaporation and transpiration, which are important parts of the biodiversity system. All these elements combined demonstrate the complex system of relationships in ecological restoration.
A global study conducted by colleagues from the Climate Scenarios for Sustainable Development team suggests that nature-based solutions could even help restore the water cycle in landscapes such as this. For more on this story, click here.
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