Abstract
<jats:p>Prosopis chilensis (Mesquite) is one of the world’s most aggressive invasive woody species, and its ecological impacts have drawn increasing scientific attention, particularly in arid and semi-arid ecosystems. In Sudan, it is rapidly reshaping Doum palm (Hyphaene thebaica) forests, yet its effects on native forest ecosystems remain poorly quantified. This study aimed to: (i) assess tree species composition and structure, (ii) evaluate the impact of P. chilensis invasion on species richness and native species abundance in H. thebaica forests. A stratified random sampling approach was employed across 59 plots within three forests reserves, namely Alhelgi, Geli and Um Bashim. P. chilensis showed overwhelming dominance in Alhelgi and Geli forests, with highest densities of 131 and 60 trees ha⁻¹, and accounting for 83% and 86% of total tree density, and relative abundance of 63% and 71% of total tree stems, respectively. In contrast, P. chilensis was absent in Um Bashim forest. H. thebaica was the dominant native tree species, with the highest Importance Value Index (IVI) of 137. A total of nine species, belonging to seven genera and six families, were recorded across the studied forests. Within the invaded forests, Pearson’s correlation confirmed that increasing of P. chilensis abundance significantly reduced species richness (R= -0.34, p=0.021). While Kendall’s tau confirmed a significant decline in native species abundance at the community level (τ = −0.22, p = 0.036). At the individual species level, this negative effect was not statistically significant for most species, except for Vachellia nilotica, which showed a significant decline (τ = −0.28, p = 0.022). In addition, the findings reveal P. chilensis as a formidable and accelerating threat to Doum palm forests’ integrity. The study recommends integrated management strategies, including the control of P. chilensis and restoration of native vegetation, to safeguard these dryland ecosystems.</jats:p>