Detection of land cover change helps in the understanding of how humans modify the natural environment.Modification is attributed to both restoration and degradation processes.Such information guides decisions on miti...Detection of land cover change helps in the understanding of how humans modify the natural environment.Modification is attributed to both restoration and degradation processes.Such information guides decisions on mitigating landscape degradation and advancing restoration.This study sets to determine land cover changes from 1973 to 2013 in the Malewa River Basin(1,760 km^2)in central rift valley,Kenya.Satellite imageries from Landsat(Landsat Multispectral Scanner,1973;Landsat TM(Thematic Mapper),1986;ETM+(Enhanced Thematic Mapper Plus),2000;and SPOT,2013)were analyzed using various imaging techniques available in ArcGIS 10.1 and ERDAS Imagine software.The results showed a cumulative growth of 25,617.0 ha(28.8%)in area under cropland,an increase of 4,310.1 ha(11.3%)in forestland and 688.0 ha(490.7%)of wetland.There was a net decrease of 28,953.8 ha(72.2%)in the area under shrubland and 1,747.4 ha(19.2%)under grassland.The findings suggest that increased demand for arable land is mainly driven by food and income needs of the human population.This exerted enormous pressure particularly on shrublands and grassland.Increased forest cover suggests an improvement in forest restoration efforts during the last ten years.There is need to manage expansion into new arable areas by improving land productivity and tackling the drivers of land cover change.展开更多
文摘Detection of land cover change helps in the understanding of how humans modify the natural environment.Modification is attributed to both restoration and degradation processes.Such information guides decisions on mitigating landscape degradation and advancing restoration.This study sets to determine land cover changes from 1973 to 2013 in the Malewa River Basin(1,760 km^2)in central rift valley,Kenya.Satellite imageries from Landsat(Landsat Multispectral Scanner,1973;Landsat TM(Thematic Mapper),1986;ETM+(Enhanced Thematic Mapper Plus),2000;and SPOT,2013)were analyzed using various imaging techniques available in ArcGIS 10.1 and ERDAS Imagine software.The results showed a cumulative growth of 25,617.0 ha(28.8%)in area under cropland,an increase of 4,310.1 ha(11.3%)in forestland and 688.0 ha(490.7%)of wetland.There was a net decrease of 28,953.8 ha(72.2%)in the area under shrubland and 1,747.4 ha(19.2%)under grassland.The findings suggest that increased demand for arable land is mainly driven by food and income needs of the human population.This exerted enormous pressure particularly on shrublands and grassland.Increased forest cover suggests an improvement in forest restoration efforts during the last ten years.There is need to manage expansion into new arable areas by improving land productivity and tackling the drivers of land cover change.
