Omo-Turkana Research Network

Situation analysis summary: Ecosystem services in the Omo-Turkana basin

To synthesize the social and ecological impacts across such a large spatial scale, we have employed an ecosystem services (ESS) model. This allows us to plot the changes in ecosystem services within a systems diagram, to identify which groups within the social-ecological systems (SES) may be affected and to assess whether the changes are likely to be positive or negative. Framing the results through an ESS lens has the advantage of reducing the number of issues to be analyzed for different groups of actors within the region, in order to investigate variation in impacts across all groups. The model acknowledges three major categories of ecosystem services: regulating, provisioning, and cultural services.

Regulating ecosystem services are those that ecosystems provide by acting as regulators, e.g., regulating the quality of air and water or by providing flood and disease control. Through the construction of the Gibe III dam, the mediation of the hydrological cycle within the Basin is altered from its pre-dam state, permanently dampening the hydrological cycle (see the hydrology blog post for further information). This causes reduction in peak flows and flooding and increasing control of both water quality and quantity during floods and droughts. While this supports other ecosystem services, the pre-dam ecosystem was adapted to this hydrological variability, which increases connection with the flood plain and productivity, and thus the regulation may negatively affect nutrient flows and nutrient availability, which reduces soil fertility and the primary productivity of Lake Turkana (see the ecology blog post for further information).

Provisioning ecosystem services are those through which ecosystems provide material or energy outputs. Gibe III will regulate the availability of water, thereby supporting irrigation. Given climate projections for the region show rainfall becoming more variable, increased regulation may be critical in supporting provision of water in the future. However, increased irrigation has implications for equitable access to that water, and communities in the region practicing traditional livelihoods may see their water-based provisioning ESS diminished, firstly for agriculture, given reduced access to the river and reduced water quantity in the Omo and Lake Turkana once irrigation begins. Also, for drinking water, as ground water levels change. The kinds of crops cultivated in the Basin will also change dramatically, from food crops for consumption by local people, such as sorghum, to commodity crops for both domestic use and export, such as sugarcane and cotton. Irrigation and efficiency of scale will likely increase the sum output of provisioning ESS from the region but decrease the provisioning ESS related to staple foodstuffs. Decreased quality of riverine forest and disappearance of the bush cover will reduce the provision of wild foodstuffs and will reduce the availability of raw materials for fuel, fodder, and medicinal resources for indigenous populations. Similarly, changes in water availability and land access for dry season grazing will negatively influence the rearing of animals in the Lower Omo and around Lake Turkana, reducing the provisioning ESS related to animal products. Early results show that reductions in nutrient inflow are negatively influencing productivity in Lake Turkana and reducing fish yields. Therefore, while provisioning ESS will increase overall, with benefits at the national scale, there will be a reduction in the provisioning ESS that local food systems are dependent on. Hence, this is likely to result in an increase in food insecurity, with resulting mobility, and the potential for further environmental degradation.

Cultural ecosystem services are non-physical services that the ecosystem provides to humans. Remodeling the landscape of the Basin is likely to precipitate displacement of indigenous groups, constraining physical interactions with the land, and divorcing people from their cultural heritage, their sense of place and belonging. There is potential for integration of displaced populations into alternative livelihoods e.g., jobs in the new plantations. However, the stress of such change can affect both mental and physical health, and these impacts are likely to be exacerbated by the conflicts that are already occurring and anticipated to increase.