Floristic structure, pasture typology and grazing potential of natural rangelands in Benin

Abstract

Natural rangelands are central to pastoral livestock production in Benin but are increasingly threatened by climatic variability, agricultural expansion, and overgrazing. This study characterized and evaluated natural pastures as part of a national assessment of grazing potential.Phytosociological surveys covering 180 plots across Benin, excluding protected areas and the Littoral department, recorded 880 plant species with their biological, phytogeographical and abundance-dominance characteristics. Detrended Correspondence Analysis and Ward hierarchical clustering identified pasture types, validated by PERMANOVA (Bray-Curtis dissimilarity, 999 permutations). A Spearman correlation identified predictors of forage productivity, and carrying capacity (CC) estimates were tested by sensitivity analysis.Five phytopastoral units were identified, dominated by Tridax procumbens-Pennisetum polystachion, Combretum collinum-Tephrosia flexuosa, Parinari curatellifolia-Panicum maximum, Annona senegalensis-Andropogon pseudapricus, and Andropogon gayanus, and were statistically well differentiated (PERMANOVA: F4,37 = 4.17, p < 0.001, R² = 0.311). Unpalatable species contribution was the main predictor of reduced productivity (ρ = −0.90, p = 0.037). Herbaceous biomass ranged from 1.58 to 3.86 t DM ha⁻¹ across pasture types.Grazing quality remained low because of shrub encroachment and the high contribution of unpalatable species, which constrained forage production and carrying capacity. These findings provide a national baseline to guide differentiated rangeland restoration and grazing management in Benin.