Influence of Parkia biglobosa (Jacq.) R. Br. Ex G. Don on the Herbaceous Vegetation in the Katouré Valley of the Commune of Nyassia (Basse Casamance-Senegal)

Aims: Trees outside of protected areas play an important role in providing ecosystem services. They participate in the development of the mat by creating favorable conditions for the development of grasses. The influence of trees on the development and distribution of grasses is not well known. It is in this sense that this study was conducted to determine the effect of Parkia biglobosa cover on the composition, diversity, structure and spatial distribution of herbaceous vegetation. Place and Duration of Study: The study was carried out in the commune of Nyassia in Lower Casamance on a site identified as a Parkia biglobosa park in the Katouré valley in August 2021. Methodology: Floristic surveys were conducted under (R, R/2, R and 2R) and outside the control tree canopy. Results: It was found that the number of species under the tree canopy ranged from 13 to 16 species and was greater than that observed outside the canopy (6 species). Species such as Bracharia deflexa, Cyperus esculentus, Echinochloa colona, Indigofera heudelotii and Pentodon pentandrus were the most frequently encountered in the surveys under the tree canopy (0R, R/2 and R). In contrast, Andropogon gayanus and Bulbostylis capillaris were the most abundant species in the noncanopy surveys. The canopy cover of P. biglobosa, which ranged from 70±17.6 (2R) to 83±19.4 (R/2), was higher than in the uncovered level (54±15.4). Diversity analysis  revealed that the canopy surveys 0R (0.80±0.06), R/2 (0.81±0.04) and R (0.77±0.06) were the most diverse. Conclusion: The presence of Parkia biglobosa influenced the presence of herbaceous species and improved habitat conditions.