Spatial patterns of phylogenetic diversity and neo- and paleo-endemism in Kenyan Asteraceae

Abstract Background Asteraceae is one of the largest plant families in Kenya and constitutes a major evolutionary lineage contributing significantly to the country’s floristic diversity. However, a spatial phylogenetic evaluation of the family remains underexplored. Here, we examine the spatial, taxonomic, and phylogenetic patterns of Kenyan Asteraceae, highlighting key conservation priorities. Results The humid central and western highlands exhibited the highest taxon richness (TR), weighted endemism (WE), and phylogenetic diversity (PD). Significant phylogenetic clustering was observed in the central and western highlands, whereas a small number of grid cells exhibited phylogenetic overdispersion in the arid northern region. Centers of neo-endemism were found in the humid central region, whereas paleo-endemism was centered in the northern arid region. Mixed-endemism hotspots were predominantly concentrated in the northern and southern coastal regions. Neo-endemism within Asteraceae is taxonomically widespread, with multiple tribes exhibiting high genus-level richness and numerous genera represented by species occurring in regions identified as centers of neo-endemism. Vernonieae, Senecioneae, Astereae, Inuleae, Cichorieae, and Gnaphalieae were prominently represented in these regions, whereas several smaller tribes were composed exclusively of genera restricted to neo-endemism hotspots. In contrast, paleo-endemism centers hosted relatively fewer genera and lacked tribe-specific restriction; representation was largely shared across Vernonieae, Astereae, Inuleae, and Senecioneae. Conclusion The spatial patterns of Asteraceae in Kenya reflect a dual evolutionary dynamic, where humid montane regions promote recent diversification while arid northern landscapes preserve older evolutionary lineages, with climatic gradients likely acting as the primary driver. The identification of phylogenetic endemism outside the existing protected area network suggests potential conservation gaps in Kenya’s arid northern region, although further research is needed to corroborate this pattern.