Opoku Pabi

Cocoa agroforestry for increasing forest connectivity in a fragmented landscape in Ghana

Abstract In Ghana, farmers perceive protected forests as land banks for increasing agricultural productivity to support subsistence living. This has led to fragmentation of existing protected forests. Two of such reserve forests namely Bia Conservation Area and Krokosua Hills Forest Reserve have been encroached through lumbering for timber and area expansion of no-shade cocoa production systems. The purpose of this study was to develop a multi-disciplinary strategy to increase forest connectivity using cocoa agroforest corridors. Biophysical assessments involving satellite images for vegetation patterns, and expert data from a decision support system were used to select suitable sites for the corridor within a Geographic Information System framework. Socio-economic assessments of the opportunity costs of alternative farming systems to cocoa agroforestry in the delineated corridors show that while timber trees planted within cocoa agroforests settings would help offset the yield losses in cocoa shade-yield relationships compared to full sun-production systems, the on-farm benefits of cocoa agroforestry alone are insufficient to justify the adoption. Paying farmers premium prices for cocoa and substantial off-farm environmental and ecosystem services under agroforestry systems can tip the balance towards adoption.

Relating land use and land cover to surface water quality in the Densu River basin, Ghana

Abstract The Densu River basin is one of Ghanas most reliable freshwater sources, though greatly stressed through pervasive land-use activities. This warrants that water quality variability be understood in relation to land use and land cover (LULC) processes in the basin. In this paper, water quality variables and LULC attributes were evaluated using multivariate techniques such as Pearsons correlation and linear regression to decipher the relationship between them. The study found water quality variability to be influenced by both seasonality and geographical location. While water quality variables such as pH, turbidity, DO, total suspended solids, Ca2+, K+ and -N relatively were increasing during the rains, T, electrical conductivity, TDS, Cl− and -P were conversely higher in the dry season. Consistent with other studies, spatial differences observed for water quality variables probably reflect local variability in land use, geology, lithology and soil properties across the basin. Adequately vegetated sub-basins experienced minimal load of nutrients compared with other land cover types. Temperature, pH, turbidity, dissolved oxygen, phosphate-phosphorus and nitrate-nitrogen in surface water could be estimated from multiple regression analyses, using land cover information. We recommend that riparian vegetation of the basin is conserved while urban effluent discharges into running water are minimized, under an integrated water management programme.

West Africa – Water Resources Vulnerability Using a Multidimensional Approach: Case Study of Volta Basin

Changes in climatic conditions have been evident over West Africa in the past decades. Decrease in rainfall amount led to severe droughts during the 1970s and 1980s. There has been a shift of the climatic zones in a southerly direction. Consequently, most of the Volta Basin in Burkina Faso is now located in the Sahelian and Sudano-Sahelian zones. As a consequence of instability in the rainfall pattern, many rivers have dried up, large tracts of land cover have been degraded, and the water table is drawing down.