Browsing by Author "Jeppesen Erik"

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    Implications of changes in land use on soil and biomass carbon sequestration: a case study from the Owabi reservoir catchment in Ghana
    (Taylor & Francis, 2023) Amissah Eric; Adjei-Gyapong Thomas; Antwi-Agyei Philip; Asamoah Eric; Abaidoo R. C; Jeppesen Erik; Neumann Andersen Mathias; Baidoo Emmanuel
    Land use changes affect soil and biomass carbon sequestration potential of the agroecosys tems of most Sub-Sahara Africa facing rising temperatures due to global climate change. One such ecosystem is the Owabi reservoir catchment in Ghana, which has undergone extensive changes in land use through urbanization. Our study aimed to determine the impact of the spatial and temporal variability of the different land uses on soil and biomass carbon storage in the Owabi catchment. Land use/cover maps were elaborated using SPOT satellite images of 30 30-m resolution and Erdas Imagine and ArcGIS Pro softwares. Soil and vegetation were sampled along three transects in the Y plane in early 2014. Nested plot design and temporary sample plots of 50 50 m were demarcated within a 1 ha plot in each of the land uses. Trees, herbs and litter were sampled to assess aboveground carbon, and soil samples were taken at 0–15 cm and 15–30 cm depth. Belowground (root) biomass was calculated using the root:shoot ratio. Seven (7) land use types – dense forest, sparse for est, grassland, cropland, wetland, settlement, and excavated land – were identified and differences in carbon stocks were assessed. Soil carbon stock (0–30 cm) ranged from 51.80 Mg/ha in dense forest to 7.00 Mg/ha in excavated land. Our study showed that the conversion of forest lands to other land uses through excavation resulted in about 30-folds loss in carbon and also a major loss of carbon in the catchment from c. 1.4 106 Mg C in 1990 to 0.55 106 Mg C in 2014. Enhancing forests or growing trees to sequester carbon seems to be the optimum choice among the seven land uses if the introduction of paymentfor environmental services options is considered.
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    Land Use and Land Cover Changes in the Owabi Reservoir Catchment, Ghana: Implications for Livelihoods and Management
    (MDPI, 2019) Antwi-Agyei Philip; Kpenekuu Felix; Hogarh ,Jonathan N.; Obiri-Danso Kwasi; Abaidoo R. C; Jeppesen Erik; Andersen Mathias Neumann
    Reservoir catchments in Ghana have undergone significant changes in recent years with major implications for socio-economic development and local livelihoods. We studied land use and land cover changes and their impacts on livelihoods in the Owabi reservoir catchment from 1970 to 2014 using Landsat, ERDAS Imagine and Arc Geographic Information System (ArcGIS 10.2) software supplemented with participatory approaches including focus group discussions, key informant interviews and questionnaire surveys with 400 households. Our results showed that, since 1970, 24.6% of high-density forests and 15.8% of sparse forests have disappeared, while the built-up areahas increased from 9.8% to 56.6%. Additionally, the proportion of bare soil (areas that do not have vegetation cover due to forest clearing and other anthropogenic activities) has increased, while the areas of waterbodies have declined. We identified urbanisation and lack of community involvement in catchment management as the key factors driving the land cover changes that have adversely affected the livelihoods of the local fringe communities. This study highlights the threats from urbanisation to land cover changes and identifies the key drivers of land use change. For effective and sustainable management of natural resources, the local communities should be more actively involved in the decision-making process regarding the management of their individual catchments.