标题：Effects of Landuse and Land Cover Changes on the Extent and Distribution of Afroalpine Vegetation of Northern Western Ethiopia: The Case of Choke Mountains
摘要：The highlands of Ethiopia host the afroalpine and sub-afroalpine vegetation, one of the major vegetation types of Ethiopia. Due to the rugged topography and high population pressure, these regions have experienced sever land degradation. The main objective of this study was to investigate the dynamics in landuse/land cover and its effect on the extent and distribution of afroalpine vegetation. Four periods of Landsat TM for 1986, 1995, 2005 and 2011 were analysed. Vegetation study was conducted using systematic sampling by laying line transects along elevation gradients. Group discussion was made with two representative community groups of the study area. From remote sensing data four landuse/land cover types were identified: Crop land, ericaceous forest, grassland and shrub land. The result showed that the cropland had increased by 206% between 1986 and 2011, whereas ericaceous forest, grasslands and shrublands have decreased by 79, 40 and 17%, respectively in the same period. The vegetation analysis showed that 31 plant species belonging to 19 families were recorded. Out of these species, only four species were from a member of tree layer and 27 species were from herbs, grasses and shrubs categories. Erica arborea and Euryops antinorii were found the dominant from woody species and herbaceous plants respectively. Results from group discussions reveled that Choke Mountain ranges were historically covered by ericaceous dominating mosaic forest. However, the extent of ericaceous vegetation is now greatly declined due to anthropogenic disturbances. Based on our result we recommend community based resources management scheme in the afroalpine areas of Choke Mountain ranges where the community should be allowed to use sustainable grazing while protecting the woody vegetation. However, crop farming in the afroalpine belts should be strictly prohibited to conserve the entire landscape.
