Earth mounds with the presence of palms have high evolutionary history in the Cerrado–Caatinga ecotone

The presence of palms on earth mounds may increase community phylogenetic diversity (PD) by promoting facilitation and acting as natural perches that enhance species recruitment. We investigated whether palm presence and mound size affect the phylogenetic diversity (alpha and beta) and structure of woody vegetation. We selected 42 earth mounds in an ecotone between the Cerrado and Caatinga biomes: 15 with Copernicia prunifera (Mill.) H.E. Moore, 12 with Astrocaryum vulgare Mart., and 15 without palms. We sampled the woody vegetation, measured the area of mounds and collected the geographic coordinates in order to construct a distance matrix. We then built a phylogenetic tree and calculated the standardised effect sizes of phylogenetic diversity (ses.PD) and phylogenetic distances (ses.MPD and ses.MNTD), in order to control for species richness. We partitioned phylogenetic beta diversity into its turnover and nestedness components. Earth mounds with Astrocaryum vulgare exhibited higher ses.PD and phylogenetic overdispersion (ses.MPD = 0.76; ses.MNTD = 0.88; p < 0.05). By contrast, mounds with Copernicia prunifera displayed a random phylogenetic structure (ses.MPD = 0.02; ses.MNTD =  − 0.21; p > 0.05), whereas mounds without palms exhibited lower ses.PD and phylogenetic clustering based on ses.MPD (− 0.70; p < 0.05). The dissimilarities between mounds were driven by species turnover rather than geographic distance. Additionally, larger mounds exhibited higher PD. Our study highlights the potential of palms, particularly Astrocaryum vulgare, to promote the phylogenetic diversity of woody plant lineages on earth mounds, suggesting that their use is an effective strategy for ecological restoration in challenging environments.