title: Mapping deforestation and urban expansion in Freetown, Sierra Leone, from pre- to post-war economic recovery.
abstract: Freetown, the capital of Sierra Leone has experienced vast land-cover changes over the past three decades. In Sierra Leone, however, availability of updated land-cover data is still a problem even for environmental managers. This study was therefore, conducted to provide up-to-date land-cover data for Freetown. Multi-temporal Landsat data at 1986, 2001, and 2015 were obtained, and a maximum likelihood supervised classification was employed. Eight land-cover classes or categories were recognized as follows: water, wetland, built-up, dense forest, sparse forest, grassland, barren, and mangrove. Land-cover changes were mapped via post-classification change detection. The persistence, gain, and loss of each land-cover class, and selected land conversions were also quantified. An overall classification accuracy of 87.3 % and a Kappa statistic of 0.85 were obtained for the 2015 map. From 1986 to 2015, water, built-up, grassland, and barren had net gains, whereas forests, wetlands, and mangrove had net loses. Conversion analyses among forests, grassland, and built-up show that built-up had targeted grassland and avoided forests. This study also revealed that, the overall land-cover change at 2001-2015 was higher (28.5 %) than that recorded at 1986-2001 (20.9 %). This is attributable to the population increase in Freetown and the high economic growth and infrastructural development recorded countrywide after the civil war. In view of the rapid land-cover change and its associated environmental impacts, this study recommends the enactment of policies that would strike a balance between urbanization and environmental sustainability in Freetown.
authors.affiliation: Magbosi Land, Water and Environment Research Center (MLWERC), Sierra Leone Agricultural Research Institute (SLARI), PMB 1313, Mile 91, Northern Province, Sierra Leone. l.mansaray@slari.gov.sl.|Institute of Remote Sensing and Information Application, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China. l.mansaray@slari.gov.sl.|Key Laboratory of Agricultural Remote Sensing and Information Systems, Zhejiang Province, Hangzhou, 310058, People's Republic of China. l.mansaray@slari.gov.sl.
authors.forename: Lamin R
authors.initials: LR
authors.lastname: Mansaray
authors.affiliation: Institute of Remote Sensing and Information Application, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China.|Key Laboratory of Agricultural Remote Sensing and Information Systems, Zhejiang Province, Hangzhou, 310058, People's Republic of China.
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Huang
authors.affiliation: Magbosi Land, Water and Environment Research Center (MLWERC), Sierra Leone Agricultural Research Institute (SLARI), PMB 1313, Mile 91, Northern Province, Sierra Leone.
authors.forename: Alimamy A
authors.initials: AA
authors.lastname: Kamara
mesh_terms: D000383:Agriculture; D003247:Conservation of Natural Resources / Q000191:economics / Q000379:methods*; D057217:Economic Development; D004784:Environmental Monitoring / Q000191:economics / Q000379:methods*; D058735:Environmental Policy; D065928:Forests; D065948:Grassland; D058998:Remote Sensing Technology; D012807:Sierra Leone; D014507:Urbanization; D014857:Warfare; D053833:Wetlands
keywords: Change detection; Civil war; Freetown; GDP growth; Land-cover; Population growth