Exploitation des ressources naturelle et dynamique actuelle sur les versants du massif de l'atacora: Secteur perma - Toucountouna (Nord -Ouest Benin)

Abstract

The Exploitation of the natural resources and current land-use dynamics of the slopes of the Atacora Chaîn were studied by means of a multi-disciplinary approach. Agriculture, breeding, rock exploitation (quarzites especially), forest resource exploitation and collection of medicinal plants are the principal forms of exploitation recorded. The woody species richness on these slopes varies from 5 to 175 species within plot of 900 m 2 following the topographic position. The index of Shannon and the Equitability of Pielou range from 1.6 to 3.4 bits and 0.6 to 0.9 bits, respectively. The basal area and the density of woody species were, in average, 2.6-12.7 m²/ha and 10.75-42.5 stems/ha, respectively. The ground loss is on average 1-2 cm thickness on the summit, 1-12 cm on the cliff, and 1-6 cm on the mid-slopes. The impact of the exploitation of the natural resources resulted in a regression of the natural plant formations at the expense of the anthropic plant formations. On the whole, from 1949 to 2003, this regression includes 63% of the total land area of the study area.