Theory question 104
Nigeria: Physical Setting(a) Draw an outline map of Nigeria. On the map, show the annual distribution of rainfall (b) Highlight three effects of rainfall on the distribution of vegetation in Nigeria. (c) Describe four characteristics of the Guinea Savanna.
Show the model answer
(a) Outline map of Nigeria with isohyets: over 2,000 mm along the coast and south-east (Niger Delta, Calabar); 1,500-2,000 mm in the south; 1,000-1,500 mm in the middle belt; 500-1,000 mm in the north; under 500 mm in the far north-east (Lake Chad area); with key and title.
(b) High rainfall in the south gives mangrove/swamp and rainforest; moderate rainfall gives Guinea savanna; low rainfall in the north gives Sudan and Sahel savanna; trees get fewer, shorter and more drought-resistant northwards; grass becomes shorter.
(c) Tall grasses (up to 3 m, e.g. elephant grass) with scattered trees; trees medium height, broad-leaved, deciduous, thick bark to resist fire; gallery forests along rivers; trees such as locust bean, shea butter, isoberlinia; grasses dry up and are burnt in the dry season; covers the middle belt.
Draw and label the isohyets with values.