This paper mapped and valued key inter-related drylands ecosystem services of importance
to pastoralists, crop farmers, the tourism industry, conservationists, and policy planners in
the Ewaso Ng’iro basin, the largest of the five major basins in Kenya. We used an ecosystem
services approach where only final benefits are valued to avoid double counting. The final
benefits are ecosystem services or commodities which have an economic value. The supply
of ecosystem services depends on the functioning of ecosystems, but rarely ecological and
institutional boundaries coincide and often stakeholders in ecosystem services cut across a
range of institutional zones and scales. Land use and management influence the system
processes, properties and components that are the basis of services provision. Although
much has been written about the need to quantify and value ecosystem services, there are
fewer spatially explicit studies that delineate the supply and demand areas for ecosystem
services and assess the trade-offs between ecosystem services over space and time especially
on drylands.
Based on the spatial distribution of resources and the existing competition over these
resources, this paper assesses the current values attributed to the selected ecosystem
services. Then, by mapping existing supporting infrastructure and drivers ofland use change
such as demographic pressure, we highlight trade-offs and synergies among alternative uses
and opportunities for sustainable development. In particular, the paper identifies services
that will be lost if a particular part of landscape is modified: e.g. benefits for livestock and
wildlife can be affected by the lack of conservation of corridors and rangelands, while water
supply and irrigated crops can be compromised by increased water demand as result of
human population pressure mainly at the upstream sub-catchments.
We demonstrate the value of spatial analysis to land use investments and management
and highlight how conservation and management of ecosystem services require the understanding
of the spatial links between ecosystems and human well-being.