Using satellite remotely sensed data and geographic information system to analyse mangrove forest distribution change in Akwa Ibom State from 1986-2003

摘要

This paper utilised remotely sensed data and GIS to determining the change mangrove forests have undergone in Akwa Ibom from 1986 to 2003. The mangrove forest is known to be rich in both aquatic and terrestrial biodiversity as such a major source of rural life sustenance in the Akwa Ibom State as well as plays a vital role in ecosystems stabilization. Unfortunately, the Mangrove forest in recent times has been subjected to the effects of a growing population, economic and social pressures manifested in the form of rapid urbanization, agricultural land expansion and industrialization. At it stands, the mangrove forest is not under any known form of protection and or laws and strategies of biological resource conservation in Nigeria. Even in areas where they seem to exist, they have alienated the knowledge systems and practices of the local people. This paper therefore examines the change mangrove forests have undergone in the coastal line of Akwa Ibom State. Satellite images of Landsat TM 1986 and ETM 2003 of the study area were acquired from National Centre for Remote Sensing, Jos where change detection and analysis were done using Erdas Imagine 9.2 and ArcGis 9.2. The analysis of the images revealed that mangrove forests have change from 114103.8 ha representing 17.2% in 1986 to 107669.7ha (15.3%) in 2003. This change resulted in the loss of 96434.1 ha of mangrove forest due to the invasion of Nypa palm, activities of the oil companies, increasing rate of mangrove removal by timber logging, and local usage of mangroves. Thus, the study concludes by recommending that forest reserves should be established in Eastern Obolo where mangrove is still luxuriant with integrated sustainable forest management. Furthermore, policy makers and planners should enlighten the local people on the dangers of over exploitation and encourage them to strengthen these traditional resource management practices.