A canonical correspondence analysis (CCA) of the vegetation–environment relationships in Sudanese savannah, Senegal

The effect of environmental variables on the structure of woody vegetation within one geomorphological unit (500 ha) in Niokolo Koba National Park in Senegal was investigated. A total of 59 woody species from 25 families were recorded in 43 relevés. Canonical Correspondence Analysis (CCA) was used to evaluate the effect of soil type, topography and termitaria presence on the vegetation structure. The effects of soil type and topographical position were significant and respectively explained 15.9% and 5.2% of the species data variability. Termitaria presence was non-significant and had just a marginal influence on the vegetation structure and explained only 1.7% of the data variability. One-way ANOVA was used to evaluate the effect of soil type on total cover of particular layers. Significant differences were revealed for low shrub (0–2 m) and tree layers (6–20 m). The low shrub layer was the best developed on the plinthitic hardpan, the best-developed tree layer occurred on granite outcrops. High shrub layer (2–6 m) did not show any dependence on the soil type. In conclusion, we found that soil type and topography were the main factors affecting woody vegetation of the locality.