Assessing the ecological value of sudanese savannah woodlands through woody vegetation diversity and phytosociological analysis

Tropical savannah woodlands in the Sudan play a vital role in biodiversity conservation, climate regulation, and local livelihoods. However, existing knowledge regarding species diversity and vegetation heterogeneity in these ecosystems remains limited. This constrains a full understanding of their ecological structure and functioning, and thereby restricting understanding of ecosystem resilience under increasing anthropogenic and climatic pressures. This study assessed woody species composition, vegetation structure, and diversity patterns across selected Sudanese savannah woodlands using ecological diversity indices and phytosociological metrics within a multi-level sampling framework. A total of 5,200 individuals representing 41 woody species and 15 families were recorded in 850 sample plots distributed across four study sites. Community structure was highly dominated by a few species, with Acacia seyal Delile var. seyal exhibiting the highest ecological importance (IVI = 184.46) and accounting for 82% of relative abundance. Other dominant species included Acacia sieberiana DC. (IVI = 72.11), Terminalia brownii Fresen. (IVI = 70.04), and Dalbergia melanoxylon Guill. & Perr. (IVI = 61.77). Fabaceae was the most species-rich family (18 species), followed by Capparaceae (5 species) and Combretaceae (4 species). Diversity indices revealed considerable spatial variation among sites. Alain and Dinder recorded the highest Shannon diversity (H′ ≈ 2.05), while Alain also exhibited the greatest evenness (E = 0.8569) and Simpson’s diversity (D = 0.8476), indicating relatively balanced communities. In contrast, Umsegiea showed relatively low diversity (H′ = 0.8414) and evenness (E = 0.2764), reflecting pronounced dominance by Acacia seyal. Similar patterns of relatively low woody-species diversity and evenness have been reported in Acacia-dominated savanna woodlands in Sudan and the wider Sudano-Sahelian region (Hasoba et al., 2020). Jaccard similarity values ranged from 0.15 to 0.40, demonstrating low species overlap and high beta diversity among sites. These findings reveal substantial spatial heterogeneity across ecosystems, underscoring the need for site-specific conservation strategies to enhance resilience under climate and land-use pressures.