Floristic diversity, carrying capacity and local management of coastal rangelands in a context of climatic variability and urbanization: a case study from West Africa

Coastal ecosystems are under pressure due to climate change and increasing anthropogenic activities, especially in pastoralism proned areas. This study combined vegetation census (phytosociological surveys and biomass cuts in 120 and 40 plots, respectively) and socio-economic surveys of cattle breeders (n = 115) to (i) assess vegetation structure and influencing environmental factors, (ii) determine vegetation groups and their carrying capacity, and (iii) characterize the local uses and management of the rangelands. The study was carried out in four coastal communes (Abomey-Calavi, Grand-Popo, Ouidah and Sèmè-Podji). We used both univariate and multivariate descriptive and inferential statistics for data analysis. We recorded, 347 species from 252 genera and 88 families, the largest floristic composition being observed in Abomey-Calavi and Ouidah. Relief was the main determinant of the variation of floristic composition. The plot ordination led to three main groups (G1 dominated by Acacia sieberiana and Aristida adscensionis, G2 dominated by Imperata cylindrica and Zanthoxyllum zanthoxyloides, and G3 dominated by Cocos nucifera and Indigofera spicata). Phytomass (2.06 ± 0.68 t DM/ha - 2.48 ± 0.63 t DM/ha) and carrying capacity (0.29 - 0.39 UBT/ha/year) differed significantly between the three groups and the four communes. The typology of breeders led to three clusters, namely familial agro-pastoral farmers (6 %), typical agro-pastoral farmers (58%) and co-managed agro-pastoral farmers (36%). Herd composition, rangelands management, and adaptation strategies also differed markedly across the three clusters. However, the observed management methods are not effective for coastal range management and an integrative climate-smart management scheme is needed for sustainable pastoralism in the coastal region.