Influence of anthropization on floristic diversity and carbon stocks in a Sudano-Sahelian vegetation landscape

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Résumé

Mosaic landscapes integrating protected areas and agroecosystems with variable exploitation intensities constitute critical ecosystems for biodiversity conservation and ecosystem service provision. This study evaluated how anthropogenic pressure gradients influence plant community structure, diversity, and carbon sequestration in the Sudano-Sahelian zone of Burkina Faso. Using a stratified sampling design across four anthropization levels: (i) savannah woodland = level 1, (ii) forest-edge fields = level 2, (iii) bush fields = level 3, and (iv) homestead fields = level 4, we analyzed 80 forest plots distributed along transects from inhabited areas toward the Sissili classified forest. Within each plot, floristic composition, dendrometric parameters, and aboveground carbon stocks were measured. The results revealed a significant decline in woody species richness from savannah woodland (21 ± 4 species) to homestead fields (5 ± 1 species) (p < 0.05), alongside a reduction in aboveground carbon stock from savannah woodland (15.22 ± 6.33 t C·ha−1) to bush fields (4.06 ± 1.90 t C·ha−1). Diameter distributions across all anthropization levels showed a predominance of juvenile individuals in savannah woodland and forest-edge fields (Weibull shape parameter c ≤ 2.5). Community composition analysis revealed distinct assemblages across anthropization levels (PERMANOVA: p < 0.05). TITAN analysis identified 24 species sensitive to anthropogenic stress and one tolerant species (Parkia biglobosa). Forest-edge fields presented an intermediate diversity profile, hosting both forest and open-habitat species. These findings highlight the significant role of intermediate land-use zones in biodiversity buffering and underscore the need for management strategies reconciling agricultural intensification with ecosystem service provision.

Mots-clés

Anthropization gradient, Agroforestry, Landscape, Biodiversity conservation, Plant community composition, Aboveground carbon, Burkina Faso