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Assessing and Mapping Ecosystem Services in Offinso District, Ghana

Hapsari, Arinta (2010) Assessing and Mapping Ecosystem Services in Offinso District, Ghana.

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Abstract:Forest and tree based ecosystems provide numerous services that constitute the livelihood of local people. The identification of what are the ecosystem services known and important by local people contributes in giving a better understanding of the relation between the forests and tree based ecosystems and the services that they provide for them. The aim of this study is assessing and valuing the main provisioning services provided by the forest and tree-based ecosystems, based on the community perception and compares this with the potential market value of the locally not recognized or appreciated carbon sequestration. There are five main steps in this study to asses and value the ecosystem services: 1) generating land cover as basic spatial information; 2) identification of the services provided by the ecosystem; 3) identification the criteria and indicators that can be used as the basis for valuation and mapping; 4) GIS techniques to map the ecosystem services valuation; 5) Compare the provisioning services based on people perception and the market value of the locally not recognised carbon sequestration service. Discussion, interviews and questionnaires were done to obtain the information on valuation of the ecosystem services from the local community. 4 main land cover types were identified as service provider: annuals, forest, grass and teak monoculture. Annuals appear in two different land uses types, farmland and agro-forest. From this study reveals that, provisioning services are recognized by all respondents from different gender, education level and villages. The main provisioning services are bush meat, grass, fuel wood, medicinal plants and lumber. One of the supporting services that is recognized by local communities is maintaining soil fertility and the few of regulating services are water and fresh air provision. However, when carbon sequestration knowledge was being explored, none of the respondents recognized carbon sequestration as one of the services provided by the ecosystem. The criteria that used for the valuation are; 1) the importance of land cover based on its relative importance as collection place for a specific service; 2) the importance of a specific land cover type as the total services provider; 3) the availability of land cover. From the land cover valuation based on its relative importance as a collection place for a specific service, annuals (taungya) receive the highest value as collection place for bush meat, fuel wood, medicinal plants and lumber. As for grass collection, obviously grass land receives the highest value from local people. Regarding the importance of each land cover as total services provider used as the criteria, annuals, again received the highest value, followed by grass, forest and teak monoculture. The land cover valuation map as total services provider (second criterion) is then combined with the third criterion, the walking distance. It can be seen that the further people need to walk to reach the collection place, then the lower the value that they put. It shows that the dependency of the local people on annuals is high, but it is actually the value of the mixed (taungya) system. Annuals are not only capable of providing the provisioning services but also sequestering the carbon. The total carbon stored in woody biomass in study area is 3,191.46 G g. The highest carbon stored in woody biomass is registered in annuals (1,661 G g), followed by forest (1,281 G g), teak monoculture (206 G g) and grass (43 G g). For the Agro-forest, which is part of a reforestation project the sequestered carbon in 5 years time was prediction, provided that trees are left undisturbed. From the carbon prediction, agro-forest will sequester 1,796 G g carbon in 5 years time if the trees in agro-forest are left undisturbed. It means that agro-forest sequestered 743 G g carbon more from the current carbon stock, which could provide a considerable incentive to local people and convince them to manage trees sustainably. Key words: Ecosystem services valuation, local people, provisioning services, carbon sequestration.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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