The exploitation of natural resources for timber production, fuelwood use and conversion to agricultural land is increasing to such an extent that the sustainable use of many areas of the world is in doubt. This paper...The exploitation of natural resources for timber production, fuelwood use and conversion to agricultural land is increasing to such an extent that the sustainable use of many areas of the world is in doubt. This paper examines three decades of freely available Landsat satellite images of the northeastern part of Nigeria using a supervised classification based technique to create maps of vegetation change in Yobe State. The maps are then used to examine the temporal and spatial aspects of changes which have occurred in the context of previous evidence and literature. The results indicate that the vegetation of the area has drastically reduced since the 1970’s. However, as this study shows, the pattern of these changes is complicated and cannot be explained by any single physical or anthropogenic causal factor. Similarly, evidence from ground truthing investigation indicates the importance of fuelwood collection to the deforestation process within the region. This article shows the value of an existing remote sensing and image processing methodology for the assessment of vegetation change in developing countries in relation to the sustainable management of natural resources. The study also discusses the overall change within the study area and discusses several potential causative factors of the observed patterns of change.展开更多
Settled in the lower valleys of the Logone,Chari and Yobérivers,in a region now shared by Cameroon,Chad,and Nigeria,the Sao-Kotoko are an ancient people of Central Africa.Composed of groups distinguished by their...Settled in the lower valleys of the Logone,Chari and Yobérivers,in a region now shared by Cameroon,Chad,and Nigeria,the Sao-Kotoko are an ancient people of Central Africa.Composed of groups distinguished by their language and way of life,they gradually coalesced around influential cities,laying the foundations for a civilisation that would leave a lasting impact.展开更多
文摘The exploitation of natural resources for timber production, fuelwood use and conversion to agricultural land is increasing to such an extent that the sustainable use of many areas of the world is in doubt. This paper examines three decades of freely available Landsat satellite images of the northeastern part of Nigeria using a supervised classification based technique to create maps of vegetation change in Yobe State. The maps are then used to examine the temporal and spatial aspects of changes which have occurred in the context of previous evidence and literature. The results indicate that the vegetation of the area has drastically reduced since the 1970’s. However, as this study shows, the pattern of these changes is complicated and cannot be explained by any single physical or anthropogenic causal factor. Similarly, evidence from ground truthing investigation indicates the importance of fuelwood collection to the deforestation process within the region. This article shows the value of an existing remote sensing and image processing methodology for the assessment of vegetation change in developing countries in relation to the sustainable management of natural resources. The study also discusses the overall change within the study area and discusses several potential causative factors of the observed patterns of change.
文摘Settled in the lower valleys of the Logone,Chari and Yobérivers,in a region now shared by Cameroon,Chad,and Nigeria,the Sao-Kotoko are an ancient people of Central Africa.Composed of groups distinguished by their language and way of life,they gradually coalesced around influential cities,laying the foundations for a civilisation that would leave a lasting impact.
