Trade-offs or synergies?: assessment of ecosystem services in multi-use small reservoirs in Burkina Faso [Abstract only]

Small reservoirs (SRs) development, as a strategy to enhance food and water security in water-scarce regions, has long attracted the interests of governments and development agents. The main argument put forward was that by providing water for small-scale agriculture, they can cushion the impacts of drought and rainfall variability on vulnerable and less-developed regions. Because of the dominance of interests in small-scale irrigation, performance assessments of SRs have concentrated on irrigation outcomes. The multiple non-irrigation uses/benefits and potential negative externalities were largely neglected in the measurement of their performance. The publication of Millennium Ecosystem Assessment in 2005 triggered the concept of ‘ecosystem services’ and prompted both academia and policy decisions to consider multiple effects/impacts of human activities on natural capital, ecosystem services, and human wellbeing. Along the lines of the surge in thoughts in ‘ecosystem services’, SRs, besides irrigation use, could generate multiple benefits such as improved access to domestic water, enhance women’s position, recreation, livelihood diversification, fisheries, water availability for livestock, limiting floods, and increased biodiversity. On the other hand, SRs may have unwanted side-effects such as environmental deterioration, decrease in water quality, adverse health impacts (e.g., harbour mosquitos), and reduce environmental flows and ground water recharge. Thus, SRs’ performance need to be assessed against these multiple benefits/dis-benefits and whether there exist trade-offs or synergetic relationship. In the context of ecosystem services (ES), trade-offs between ES arise from management and/or utilization choices made by humans, which can change the type, magnitude, quality and relative mix of ES. Trade-offs occur when the provision of one or more ES is reduced as a consequence of increased use of another ES. In some cases, trade-offs may be an explicit choice; in others, it may take place without explicit account or even without awareness of the decision makers. As human activities transform ecosystems to obtain more of specific services, other services tend to diminish (trade-offs). Understanding how trade-offs operate temporally and spatially in various ecosystems and analysis of either to minimize the trade-offs or find synergetic solutions could provide decision support evidence for sustainable management of natural resources and human wellbeing. Most parts of Burkina Faso (BF) suffer from physical water scarcity and irregular distribution of groundwater. SR development has been promoted as a key strategy aiming at enhancing water and food security in BF. A conservative estimate shows that there are about 1500 SRs in BF. These are used for small-scale irrigations, livestock, and domestic purposes. From 2002 BF has initiated a program to develop village irrigation, which facilitates the exploitation of all the irrigable areas around the SRs and inland valleys. On the other hand these reservoirs may have negative effects such as flooding and health impacts. Using an ecosystem services-based approach on a sample of small reservoirs in BF, this study investigates the multiple ecosystems services/dis-services, their trade-offs, and synergetic relationships. This provides evidence for improved management and utilization of the SRs in order to minimize the trade-offs and enhance synergetic solutions that ultimately contribute to water and food security.