Integrating ecosystem services into conservation planning in South Africa
Thesis (PhD (Botany and Zoology))—University of Stellenbosch, 2009.
Natural ecosystems provide many services that are crucial for sustainability and health of human society. Ecosystem services are the benefits people obtain from ecosystems (i.e. goods and services) and can be classified into provisioning (e.g. fibre, fuel wood); regulating (e.g. water and climate regulation); supporting (e.g. soil retention) and cultural (e.g. aesthetic value). The growing global human population and other threats place enormous stress on the natural environment reducing its capability to provide services. According to the Millennium Ecosystem Assessment, more than 60% of ecosystem services worldwide are being degraded or used unsustainably. The need to safeguard ecosystem services is therefore urgent. Biodiversity underpins most ecosystem services, but the functional relationship between biodiversity and services is not well known. A wide range of strategies exist for safeguarding biodiversity, but no such approaches have been developed for ecosystem services. A key conservation strategy is the use of systematic conservation planning to identify priority areas where effort should be focused. There are calls for the inclusion of ecosystem services into conservation planning geared towards biodiversity. Ecosystem services have been used for many years as an additional rationale to justify biodiversity conservation and it is often assumed that conserving biodiversity will also conserve services. However, it is unclear how different facets of biodiversity relate to different services and to what extent conserving biodiversity will safeguard services. This thesis addresses a range of issues relating to the integration of ecosystem services into conservation planning in South Africa. I first investigated the status of ecosystem services in conservation planning worldwide by reviewing the conservation planning literature from 1998 to 2005. Ecosystem services are clearly not adequately addressed in conservation assessments. A critical barrier preventing the inclusion of ecosystem services in conservation plans is the lack of spatially-explicit data. I developed a methodology for mapping ecosystem services in South Africa and mapped the distribution of five important ecosystem services (surface water supply, water flow regulation, carbon storage, soil retention and accumulation). Using the five services to examine relationships within services and between biodiversity revealed a lack of congruence between services and different levels of congruence with biodiversity features. However, including ecosystem services in a biodiversity assessment captured at least thirty percent of each of three services selected for the study. Nevertheless, a biodiversity plan may not necessarily capture adequate amounts of ecosystem services. Ecosystem services should be planned for explicitly instead of relying on biodiversity data. I identified priorities that met targets for five services in the grasslands of South Africa. This thesis provides new insights on planning for biodiversity and ecosystem services. The results have immediate applicability for conservation planning in South Africa. Keywords: Conservation planning, conservation assessments, ecosystem functions, ecosystem processes, ecosystem services, natural capital, biodiversity, soil, water, carbon.