Explanation:
(a) Causes of desert encroachment;
(i) Prolonged drought
(ii) Over grazing
(iii) Deforestation or uncontrolled tree felling
(iv) Bush burning
(b) Areas liable:
(I) Desert margins e.g sahel regions
(ii) Sudan Savannah, e.g Sokoto, Maiducuri
(iii) Extreme northern part of Nigeria
(c) Effects;
(i) Loss of vegetation
(ii) Changes in climate of the areas
(iii) Loss of agricultural land
(iv) Loss of animals and humans by death
(d) Methods of preservation:
(i) Afforestation i.e planting of trees
(ii) Controlled grazing
(iii) Controlled tree felling/deforestation
(iv) Controlled or legislation against bush burning