Now showing 1 - 5 of 145
- ItemOpen AccessDeforestation and Land-Cover Changes in the Forest Reserves of Southwest Nigeria(Department of Geography, Univesrity of Lagos, 2018) Fasona, M.J; Akintuyi, A.O; Udofia, S.K; Akoso, T.M; Ariori, N.A; Adeonipekun, P.A; Agboola, O.O; Ogundipe, O.T; Soneye, A.S; Omojola, A.SAs part of the sustainable wood resource supply and ecosystems management strategies, colonial Nigeria government designated/gazetted some areas as forest reserves. These reserves have over the years suffered from poor inventory, depletion and poor management. This study was carried out to inventorize of the status and evaluate the land-cover changes in forest reserves located Southwest Nigeria. Triangulated approach consisting of social surveys, remote sensing and GIS analyses and field investigation was adopted. Archived maps and interview with senior forestry officers provide data on the extent, management and challenges of the reserves. Information on the land-cover conditions was sourced from time-series Landsat image data provide. Both digital pixel-based and semi-automated feature-based image classification and interpretation techniques were adopted. Validation of interpreted maps was accomplished using collateral information from base maps and land-cover-tied GPS coordinates accumulated on the field. Forest reserves covered between 11,825.18 km2 and 12,443.77 km2 (i.e. 15 to 16 % of SW Nigeria) and many of them created before 1960. Primary (undisturbed) natural forests within the reserves decreased from about 26% in 1986 to 8.3% and 0.1% in 2006 and 2016 respectively. Minimally disturbed forests constitute about 7.6%, 2.8% and 11.9% in 1986, 2006 and 2016 respectively. Area covered by mixture of tree crop and secondary forest within the reserves increased from 1% in 1986 to 3.8% and 12.4% in 2006 and 2016 respectively. Teak/Gmelina is fast dominating the reserves and has consistently increased from about 3.7% in 1986 to 18.4% in 2016. Lack of fund and ineffective policy implementation are major challenges facing the management of the reserves. Concrete efforts must be made to reseed, regenerate and revitalize the reserves with indigenous species so as to prevent total loss of natural forest in the reserves in the near future.
- ItemOpen AccessCoastal Flooding Risk and Community Adaptive Strategies in the Western Niger Delta(Environment and Behaviour Association of Nigeria, 2003) Fasona, M.JThe Western Niger Delta is an extensive low-lying area exposed to flood risk for several months during the year from excessive discharge from sediment-laden Niger River, high rainfall from the area and coastal storm surges. This study employs remote sensing data and GIS to delineate and classify the susceptibly of the study area to flood risk. Economic and social implications of regular seasonal flooding of the area were also considered. The results show that a total land surface of about 3183.45km2 lies below 5m i.e. (between very high and moderate flood risk) and 1407km2 of this lies below 1m (i.e. very high flood risk). 88 built up areas (30 % of the total) with total area of about 9.69km2, and 78.1km2 of cultivated lands are always at the risk of serious impact by seasonal flooding. Local adaptive strategies of the inhabitants were examined and environmentally sustainable and locally appropriate coastal zone management strategies for flood management in the study area are suggested.
- ItemOpen AccessBaseline ecosystems and sensitivity to oil impacts around the lower segment of Forcados River, western Niger Delta, Nigeria(Department of Geography, University of Lagos, 2011) Fasona, M.J; Soneye, A.S.O; Nwokedi, M; Oladeinde, MOil exploration has high potential to disrupt socio-ecological systems when not properly managed. Various techniques of impact analyses are normally adopted to safeguard ecosystems at various stages of resource exploration. This study attempts to create a simplified environmental sensitivity index mapping of ecosystems to hazardous chemical leakage in the oil rich lower Forcados area of the Niger Delta using Landsat image-derived ecology data integrated with biological and socio-economic data. These were ranked using multi-criteria analysis based on ecosystems productivity, oil-ecosystem interaction, ease of cleanup, importance of fauna species to rural livelihood, and human weight including frequency of interaction with an ecosystem. The final analysis was done within GIS. The result suggests mangrove ecology as possessing the highest sensitivity to oil activities and paved surfaces have the least.
- ItemOpen AccessLand Systems response to Water Footprint in the Wooded Savannah of Nigeria(Obafemi Awolowo University Press, 2011) Fasona, M.J; Tadross, M; Abiodun, B.J; Omojola, A.SErratic space and time distribution of rainfall coupled with increase in temperature means less water. The water footprint, therefore, will be critical for future development in dry and semi-dry areas where survival for large population depends on rainfed agriculture and the natural resource stock. This study investigates the linkage between water footprint and land system changes. Present and projected future rainfall and temperature data were integrated with local eco-geographical factors and subjected to principal component analysis (PCA) to decipher the present and future pattern of water footprint. These integrated dataset was also analyzed to build change drivers which were applied to satellite image derived land-cover maps to project future land-cover pattern under both present and future climate scenario using Idrisi’s dynamic CA_Markov land change model. The results suggest the emerging and future spatial pattern of ecosystems, agricultural land-use and agrarian settlements will largely follow the water footprint. Under future climate scenario (2046-2065) galleria forest - a signature of the drier savannah - is projected to dominate much of the presently forested landscapes and this will correspondingly shift the water footprint and thus alter the spatial and temporal pattern of agricultural land-use and settlement locations.
- ItemOpen AccessAspects of natural resource use and adaptation to climate change in the Nigerian Savanna(Ibadan University Press, 2015) Fasona, M.J; Oloukoi, G; Olorunfemi, F.B; Elias, P.O; Adedayo, V.TThis study investigates indigenous knowledge and perceptions on natural resource use, climate change and adaptation among rural communities in the wooded savanna. It combines participatory rural appraisal with vegetal surveys and remote sensing and GIS analysis. The results suggest that communities’ perception on the climate is consistent with results from station data. 94% believes that the pattern of rainfall has changed and 91% believes the pattern of temperature has changed. Twenty-four tree species support the local livelihoods including construction, herbs and therapy, seed and fruit gathering, fuelwood and wood for production of charcoal. Community managed forest is scarce and no indigenous specie is cultivated on woodlot. Conflict in uses has put some local species in danger of extinction. Crop switch remains the most common form of adaptation to climate change but significant percent do not have any adaptation option. Communities are well aware of the threat of climate change and extinction of some local species and are willing to partner with other stakeholders for improved ecosystems management, but are not sufficiently mobilized. We consider that unraveling the key issues surrounding non-implementation of existing policy and programmes documents is primordial to mobilizing the rural communities to action.