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Title: Remote sensing of environmental change in the Niger Delta, Nigeria
Author: Ayanlade, Ayansina
ISNI:       0000 0004 5368 3714
Awarding Body: King's College London
Current Institution: King's College London (University of London)
Date of Award: 2015
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This study examines landuse change (LUC) in the Niger Delta of Nigeria, focusing on the drivers of change and the societal implications on the people in the Delta. This study applies both remote sensing and social research methods to evaluate the spatial and temporal change in landuse, population change, deforestation, and degradation within forest reserves; and the impacts of oil production and the effects of the changes on the Delta. A time series of Landsat TM images was used over the period from 1984 to 2011. The study evaluates a number of classification and post-classification change detection methods to examine LUC, while NDVI is used to monitor the degradation of forests. Accuracy assessment shows that Maximum Likelihood (ML) is the most accurate method, but results were still error prone. To improve classification accuracy, a Decision Tree Reclassification (DTR) method was developed that uses prior classifications and simple rules of those LUCs, which occur over time and those that do not. DTR improves the overall accuracy of the classification from 62% to 89%. The social methods used a mixed-method approach (questionnaires, interviews and focus group discussions). The methods were carefully selected and used to help explain the results of findings from remote sensing. The results are presented in two phases: (1) results of remote sensing showing the overall changes in the entire Niger Delta and specific case studies (2) results of social science survey showing the drivers of changes and their environmental and societal implications on the people in the Delta. The results show that nearly 9000 km2 forest has been lost in the Niger Delta region between 1984 and 2011, but the extent of deforestation varies from one forest type to another. Lowland rainforest is more exploited than freshwater swamp forest and mangrove forests, with approximately 40% of lowland rainforest areas lost. The urban areas expand by about 50% in lowland rainforest, but less urban expansion is noted in freshwater swamp forest (16%) and mangrove forest (38%). The study finds that assessing oil spill impacts using Landsat TM was not possible, but that oil production infrastructures (e.g. construction of canals) can be an important cause of deforestation in the Delta in exceptional cases. This is evident in the mangroves around Tsekelewu that are reduced from 200km2 in 1984 to 114km2 in 1987, because of the construction of artificial canals that have promoted regular inflow of seawater and the consequent destruction of freshwater mangroves. The results from social survey show also the drivers of LUC and deforestation in the Delta are probably multiphase including unenforced forest protection laws; corruption at all levels; pressure of immigration and increasing population; and indifference of local people to the state of the forest around them.
Supervisor: Drake, Nicholas ; Michael, Howard Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available