cover lower-elevation portions of the mountains. The high peaks, which are of the greatest biological interest, are unprotected. People The Mandara Mountains sustain a relatively dense population, despite the topography and relatively poor soils. Historically the mountains were a refuge for people resisting conquest or enslavement by states on the surrounding plains, and the mountains sustain a great diversity of languages and traditional religions. Local people developed a system of intensive agriculture involving the construction of terraces and measures to retain and improve soil fertility. Terraces were built on hillsides to protect soil from erosion, and can extend from valleys to the high mountain slopes. Crop rotation between sorghum, millet, and legumes maintains soil fertility and reduces pests. Trees are used for shade, fodder, and green manure. Khaya senegalensis and Acacia albida are the most important, along with about 30 other species. Domestic sheep, goats, and cattle are kept and fed in pens during the crop-growing season, and their manure is deposited on the terraces after each harvest. Domestic animals are allowed to graze on the terraces' plant stubble after harvest to ensure that the manure fertilizes the fields. Household, human, and plant waste is used to improve the soil on terraces. See also Pico Cão Grande Tororo Rock References External links Mandaras.info Mountain ranges of Cameroon Mountain ranges of Nigeria Volcanic plugs of Africa Volcanoes of Cameroon Volcanoes of Nigeria