ABSTRACT
“Nature” is made up of ecosystems, most of which are affected in varying degrees by humans. The biodiversity of all ecosystems is intimately involved in providing benefits to people. These benefits are referred to as ecosystem services. Development that compromises biodiversity reduces the flow of ecosystem services required for sustainability; thus development can contribute to its own demise. Agricultural development, especially in drylands, is driven by water resource development which results in the transformation of ecosystems (such as grassland and woodland ones) into cultivated ecosystems. Concomitant with this transformation is a trade-off of ecosystem services through which water provision is enhanced while soil conservation, biodiversity support, and cultural services are compromised. Although water is critical for ecosystem functions that support people and contribute to their well-being, biodiversity, which helps to provide these functions, needs space and protection from disturbance and pollution more than it needs water. In evaluating the benefits of proposed development projects against the cost of lost biodiversity and hence ecosystem services, externalities due to trade-offs in ecosystem services must be included. This requires, bridging the knowledge gaps about the role of biodiversity in the provision of water-related ecosystem services, and prudence in land appropriation by irrigated agriculture and urban sprawl.
