CHARACTERIZATION OF THE NATURAL FLORA OF THE UNDERSTORY OF THE RUBBER PLANTATIONS IN SOUTHERN COTE D’IVOIRE: CASE OF THE RUBBER PLANTATIONS OF THE CNRA ANGUEDEDOU

Objective: The study was conducted in the rubber plantations of the National Agricultural Research Centre (CNRA) of Anguédédou in the south of Côte d'Ivoire, to characterize the natural biodiversity of the undergrowth of rubber plantations, through the floristic composition and the evolution of the number of species according to the age of the plantations. Methodology and results: The methodology focused on the surface inventory. Thus, 36 surveys of 20 m x 10 m, or 200 m², were installed and inventoried through the rubber plantations of different age classes ([1 to 5 years], [6 to 10 years], [11 to 20 years] and [21 to 40 years]), abandoned rubber plantations and secondary forest. Regeneration was evaluated in plots with a 5 m (25 m²) coastline. The results have shown that rubber plantations are rich in 130 natural plant species. With the exception of rubber plantations from 1 to 5 years and especially of abandoned rubber plantations, the influence of this crop on the natural flora is felt in plantations from 6 to 10 years, with only 34 species. However, this flora evolves with the aging of the plantations. In abandoned plantations, 75 species were inventoried with a good presence of endemic species such as Chlamydocarya macrocarpa, Angylocalyx oligophyllus, Chassalia kolly, Mussaenda tristigmatica. There are also some rare and/or endangered species such as Albizia adianthifolia, Baphia nitida, Commelina benghalensis, Culcasia scandens, Gloriosa superba, Greenwayodendron suaveolens, Millettia zechiana and Milicia excelsa. The floristic similarity between abandoned rubber plantations and secondary forest, indicates a shift from abandoned rubber plantations to forest formations with high regeneration density, mainly in abandoned plantations. Conclusion and application: The study showed that the impact of rubber culture is felt on the natural flora of young rubber plantations. However, when plantations are abandoned, the environment becomes secondary forest. This investigation deserves to be carried out in other rubber plantations of other ecological zones of Côte d'Ivoire.