Economic valuation of ecosystem services for the sustainable management of agropastoral dams. A case study of the Sakabansi dam, northern Benin

Baba, C. A. K, Hack, J., 2019. Ecological Indicators

Original research (primary data)
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Abstract

Agro-pastoral dams are multiple purpose water reservoirs primarily constructed to help pastoralists and riparian farmers address water shortages in rural areas. These dams are often surrounded by a buffer zone intended to minimize sedimentation and evapotranspiration. In spite of the importance of these dams for riparian communities’ livelihoods, their sustainability is nowadays challenged by various management issues underlined by stakeholders’ perception and valuation of ecosystem services provided by the dam system (reservoir-buffer zone). Taking the agro-pastoral dam of Sakabansi village in northern Benin as a case study, we assessed, quantified and valued both actual and potential benefits derived by riparian communities from the dam system using the ecosystem services cascade model as a conceptual framework. The Aggregated Economic Value of services provided by the dam system was estimated to 128,166 (sic) based on nine ecosystem services. Fishery activities, despite causing conflicts between two major stakeholders of the dam, represented less than 0.09% of the Aggregated Economic Value. This suggests the crucial need to raise communities’ awareness on the economic value of various other benefits they derived from the dam system in order to facilitate a more comprehensive assessment of benefits and costs. We finally discussed the relevance of our valuation outputs in analysing trade-offs among services and in fostering stakeholder dialogues to inform land allocation and management at the local scale.

Case studies

Basic information

  • Case ID: INT-254-1
  • Intervention type: Protection
  • Intervention description:

    Covering initially an overall area of ca. 1246ha (discontinuous green line in Fig. 3), the protection zone of the dam is nowadays locked to a small bu er zone (present-day protection area) that was estimated to 63 ha in June 2013. Patches of remnant gallery forest and woody savannas dominated by Anogeissus leiocarpa, Vitellaria paradoxa, Dios- pyros mespiliformis, Margaritaria discoidea, Terminalia glaucescens, Ho- larrhena oribunda, Lannea kerstingii, Danielia oliveri, Detarium micro- carpum, and Acacia polyacantha were still visible. High value forage and timber species such as Khaya senegalensis, Pterocarpus erinaceus and Afzelia africana, were also found within the bu er zone even though they were heavily trimmed by pastoralists (important source of fodder during dry seasons). The bu er zone was overall characterized by un- even-aged and well-diversi ed tree species illustrated by a species richness of 62 species/ha, a stand density of 363 stems/ha for a basal area of 19.70m2/ha. Computed Shannon-Wiever diversity index (H’) and Pielou evenness coe cient (E) were respectively 1.72 and 0.97. Numerous small rodents, other mammals, bird species, and reptiles including the red-listed African crocodile nd refuge and reproduction sites within these habitats.

  • Landscape/sea scape ecosystem management: Yes
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Loss of food production  Positive Soil erosion: Quantified: At the scale of Sakabansi bu er dam, soil prevented from being eroded amounts to 197.88 m3 per year… Using the price of one load (5 m3) of a standard tip-lorry (sale of riverbed sand for construction purposes) of ca. 38.11 € (25,000 FCFA) as a relevant proxy to estimate this service o er, the value of soil prevented from being eroded is thus calculated to be 4990 € per year. --> positive effect Other: local climate regulation based on perceptions of local stakeholders “regulating services such as tree shade provided by the buffer zone and the microclimate effects that result in a cooling environment around the reservoir…. potential of the buffer zone to regulate temperature and rainfall” --> Positive effect Agri: source of pasture/fodder especially in dry seasons
    Other climate impact  Positive Soil erosion: Quantified: At the scale of Sakabansi bu er dam, soil prevented from being eroded amounts to 197.88 m3 per year… Using the price of one load (5 m3) of a standard tip-lorry (sale of riverbed sand for construction purposes) of ca. 38.11 € (25,000 FCFA) as a relevant proxy to estimate this service o er, the value of soil prevented from being eroded is thus calculated to be 4990 € per year. --> positive effect Other: local climate regulation based on perceptions of local stakeholders “regulating services such as tree shade provided by the buffer zone and the microclimate effects that result in a cooling environment around the reservoir…. potential of the buffer zone to regulate temperature and rainfall” --> Positive effect Agri: source of pasture/fodder especially in dry seasons
    Soil erosion  Positive Soil erosion: Quantified: At the scale of Sakabansi bu er dam, soil prevented from being eroded amounts to 197.88 m3 per year… Using the price of one load (5 m3) of a standard tip-lorry (sale of riverbed sand for construction purposes) of ca. 38.11 € (25,000 FCFA) as a relevant proxy to estimate this service o er, the value of soil prevented from being eroded is thus calculated to be 4990 € per year. --> positive effect Other: local climate regulation based on perceptions of local stakeholders “regulating services such as tree shade provided by the buffer zone and the microclimate effects that result in a cooling environment around the reservoir…. potential of the buffer zone to regulate temperature and rainfall” --> Positive effect Agri: source of pasture/fodder especially in dry seasons
  • Approach implemented in the field: Yes
  • Specific location:

    The village of Sakabansi (3°22′57.315′′E, 10°2′32.359′′N) is located in the commune of Nikki in northern Benin, West Africa (Fig. 1).

  • Country: Benin
  • Habitat/Biome type: Streams, rivers, riparian |
  • Issue specific term: Not applicable

Evidence

  • Notes on intervention effectivness: "This study determines the benefits of the buffer protected area through perceptions of local stakeholders on what benefits (Ecosystem services) they think the intervention provides. they then quantify some of these. and finally using this data, compare ES provisions to a counterfactual assessment, what would have happened if they hadn't protected the area. in this case, clearing the buffer zone for crop production.So for the select ES that were included in this comparison, (erosion control), effectiveness derived from this. for the other (climate regulation) effectiveness deduced only from the interviews with stakeholders note that for soil erosion, even though in the comparison it has a 'negative value' this negative value is less negative than the comparator and therefore a positive outcome overall"
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: Please select
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: No
  • Impacts for the ecosystem: Not reported
  • Ecosystem measures: n/a
  • Assess outcomes of the intervention on people: Yes
  • Impacts for people: Positive
  • People measures: "Climate impacts are relevant social impacts because attributed to specific local communities benefiting from them Additional social impacts: Fodder and timber provisioning, nuts and seeds harvesting, aesthetic value"
  • Considers economic costs: Yes
  • Economic appraisal conducted: Yes
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Mixed qualitative/quantitative
  • Is it experimental: Yes
  • Experimental evalution done: In-situ/field
  • Non-experimental evalution done: Not applicable
  • Study is systematic: