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Editor’s Choice - Do ecosystem services depend on biodiversity? Evidence from communal lands in Namibia

April 2011 (Issue 48:2)

Naidoo, R., Weaver, L., Stuart-Hill, G. & Tagg, J. (2011) Effect of biodiversity on economic benefits from communal lands in Namibia. Journal of Applied Ecology, 48, 310-316.

That functioning ecosystems provide society with services of enormous value (from carbon sequestration, through water purification to waste processing and pollination) is of course well known by applied ecologists. However the concept that natural environments should be conserved on the basis of these ecosystem services has gained political prominence relatively recently. In the context of this ‘ecosystem services framework’ for environmental decision making, an important question that has simmered among applied ecologists for two decades has achieved renewed significance: “to what extent do the services provided by an ecosystem depend on the biological diversity of the system?” Much fascinating work has addressed this question using model systems in the laboratory or under highly simplified field conditions, but there remains little empirical evidence of the relationship between varying levels of biodiversity in a natural system and the benefits felt by society. This Issue’s ‘Editor’s Choice’ uses an impressive data set from communally managed lands in Namibia to start to fill this gap in our understanding.

In Namibia, the management of large areas is formally devolved to community associations to manage as conservancies - units of land with defined boundaries and management goals. The dominant financial benefits are from ecotourism and trophy hunting. Naidoo et al. bring together data on the diversity of larger animal species and income from 50 conservancies in Namibia. Accounting for likely confounding variables (such as distance from established tourism routes), they looked at whether the species richness of larger wildlife species in general or the presence of the ‘big five’ (black rhino, lion, leopard, buffalo and elephant), were important predictors of income from tourism and hunting on a conservancy. They found that the benefits from trophy hunting are positively related to biodiversity, as represented by large wildlife species. Biodiversity also appears to be an important predictor of benefits from ecotourism, though the relationship is more complicated than for trophy hunting presumably because other factors aside from the richness of large mammals are also important in attracting tourists.

To some extent this study tells us little new - any manager of a reserve, a game scout or tourism operator in Africa will tell you that large mammals are needed to attract visitors. However by formally illustrating this relationship and putting dollar signs on the value of wildlife, Naidoo et al. make a convincing argument that conservation is not only of aesthetic or ethical importance but can yield tangible economic benefits. Such economic arguments carry weight in one of the world’s poorest regions, but are just as important for swaying decision makers in richer economies.

Valuation of services so that provision of one service can be traded off against another is central to why decision makers find ecosystem services such an attractive concept. As applied ecologists we are deeply familiar with the complexity of natural systems, the uncertainties inherent in their dynamics and the limits to our own knowledge about the linkages between ecosystem elements and the production of services (of which the relationship between biodiversity and ecosystem services is an example). It is therefore vitally important that we engage in this debate and work with economists and policy makers to improve the estimates of value attached to natural ecosystems. Naidoo et al.’s paper is a valuable first step and I hope that we will see a flush of papers in the journal which address questions of similar importance to the successful implementation of the ecosystem services framework to decision making.

Julia Jones
julia.jones@bangor.ac.uk