Characteristics of the herbaceous vegetation of three young baobab (Adansonia digitata L.) plantations in Middle and Upper Casamance, Senegal

The study was carried out in the regions of Kolda and Sedhiou, in Upper and Middle Casamance, in young baobab (Adansonia digitata L.) plantations established in 2014 to shorten the production cycle in order to reduce pressure on the increasingly threatened adult baobab populations. The objective was to assess the influence of baobab plantations on the diversity and biomass production of the herbaceous cover according to the location. The plantations consisted of fenced plots of 0.5 hectare each, subdivided into three plots. Each plot was subdivided into four subplots. In each subplot, a floristic survey was carried out with the Braun-Blanquet method. In parallel, other inventories were carried out in unfenced plots (controls) surrounding the plantations. The herbaceous biomass was harvested from 32 square-meter plots, previously delimited for the floristic inventory, with five samples taken at the four corners and in the middle. The inventoried global flora included 63 species distributed in 41 genera and 17 families, including 40 species in Dianabo, 38 in Senoba and in Sare Modika, and 46 in the control area. The index of Shannon, with 1.19 in Dianabo, 1.16 in Senoba and 1.13 in Sare Modika, and the index of equitability, with 0.62 in Dianabo and Sare Modika, and 0.60 in Senoba, differed very little from one plantation to another and from the control area, where they were respectively 1.23 and 0.63. The phytomass obtained was respectively 2.85, 6.6 and 5.1 tons of dry matter per hectare in Dianabo, Senoba, and in the control plots.