Analysis of earthworm ecology in Lamto (Côte d’Ivoire)

This study examined earthworm ecology in the Lamto Reserve (Côte d’Ivoire) in relation to vegetation cover (wooded savanna, grassy savanna, and forest) and soil depth (0–10 cm, 10–20 cm, and 20–30 cm). Sampling was carried out using the monolith method and enabled the identification of nine species distributed among three ecological groups: epigeic, endogeic, and anecic, which were differentiated by their size and the position of their clitellum. Species richness was highest in the surface layer (0–10 cm), with a slight dominance in the forest, where nine species were recorded. Mean earthworm density varied significantly, with the highest values recorded in the forest. The species Stuhlmannia zielae was dominant there, with 433.6 ± 188.86 individuals/m². The biomass of Millsonia omodeoi was higher in the wooded savanna (70.50 ± 32.44 g/m²). Analysis of variance (ANOVA) showed significant effects of vegetation type, soil depth, and their interaction on density and biomass (p < 0.05). The post hoc Tukey test indicated that the surface layer differed significantly in terms of density and biomass between the forest and the wooded savanna. These results demonstrated that earthworms were strongly influenced by environmental conditions such as soil moisture, organic matter availability, and soil structure.