Kenya’s daisies reveal two evolutionary worlds in one country

Kenya’s Asteraceae family, the lineage that includes daisies, thistles, and groundsels, is telling scientists two very different evolutionary stories at once. A new study published in BMC Plant Biology has mapped the spatial phylogenetic patterns of this major plant family across the country, revealing that humid montane regions are hotbeds of recent diversification while arid northern landscapes serve as living museums of ancient evolutionary history. The research, led by Daniel Mutavi Katumo and colleagues at the Institute of Botany of the Chinese Academy of Sciences in collaboration with the National Museums of Kenya, offers the first comprehensive spatial phylogenetic evaluation of one of Kenya’s largest plant families and highlights potential gaps in the country’s protected area network.

Asteraceae is one of the largest plant families in Kenya and constitutes a major evolutionary lineage contributing significantly to the country’s floristic diversity. Yet until now, a spatial phylogenetic evaluation of the family remained underexplored. The team set out to examine the spatial, taxonomic, and phylogenetic patterns of Kenyan Asteraceae, with the goal of identifying key conservation priorities. To do this, they combined DNA sequence data, herbarium records, and sophisticated spatial analysis techniques to build a species-level phylogenetic tree of the family and then map its evolutionary diversity across the Kenyan landscape.

The researchers sequenced newly collected specimens using the internal transcribed spacer (ITS) region of DNA, a standard molecular marker for plant phylogenetics. They combined these new sequences with publicly available data from NCBI and the Global Biodiversity Information Facility (GBIF), along with herbarium voucher details from the East Herbarium. Maximum likelihood phylogenetic analysis, evaluated with bootstrap support and the Bayesian Information Criterion, produced a robust species-level tree. The team then overlaid this tree onto a grid of 0.5-degree cells covering Kenya, calculating metrics such as taxon richness (TR), weighted endemism (WE), phylogenetic diversity (PD), and phylogenetic clustering and overdispersion indices like the net relatedness index (NRI) and nearest taxon index (NTI).

The results show that the humid central and western highlands exhibited the highest taxon richness, weighted endemism, and phylogenetic diversity. These montane regions, blessed with reliable rainfall and moderate temperatures, appear to promote recent diversification. Significant phylogenetic clustering was observed in the central and western highlands, meaning that species found there tend to be closely related to one another, a signature of rapid recent radiation. In contrast, a small number of grid cells in the arid northern region exhibited phylogenetic overdispersion, where species are less closely related than expected by chance, suggesting that these areas host lineages that have persisted through deep evolutionary time.

Perhaps the most striking finding involves the distinction between neo-endemism and paleo-endemism. Neo-endemism refers to recently evolved species restricted to a particular area, while paleo-endemism refers to ancient lineages that were once more widespread but are now confined to small refugia. The team used the Categorical Analysis of Neo and Paleo-endemism (CANAPE) to identify centers of each. Centers of neo-endemism were found in the humid central region, whereas paleo-endemism was centered in the northern arid region. Mixed-endemism hotspots, where both recently evolved and ancient endemic lineages coexist, were predominantly concentrated in the northern and southern coastal regions.

Neo-endemism within Kenyan Asteraceae proved to be 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. Several smaller tribes were composed exclusively of genera restricted to neo-endemism hotspots, underscoring how recent evolutionary radiation has shaped the family across multiple branches of its phylogenetic tree. In contrast, paleo-endemism centers hosted relatively fewer genera and lacked tribe-specific restriction; representation was largely shared across Vernonieae, Astereae, Inuleae, and Senecioneae, suggesting that these ancient lineages are scattered remnants rather than concentrated clusters.

The spatial patterns of Asteraceae in Kenya thus reflect a dual evolutionary dynamic. Humid montane regions promote recent diversification, likely because reliable moisture and varied topography create numerous ecological niches that newly evolved species can exploit. Arid northern landscapes, by contrast, preserve older evolutionary lineages, possibly because harsh conditions have acted as refugia where ancient lineages survived while their relatives disappeared elsewhere. Climatic gradients likely act as the primary driver of this dual dynamic, with rainfall and temperature shaping both where new species evolve and where old ones persist.

The identification of phylogenetic endemism outside the existing protected area network suggests potential conservation gaps in Kenya’s arid northern region. The team used the World Database on Protected Areas (WDPA) to assess coverage, and found that centers of paleo-endemism and mixed-endemism in the north and coastal areas fall largely outside formally protected zones. Although further research is needed to corroborate this pattern, the finding raises concerns about the long-term survival of ancient lineages that may be vulnerable to habitat degradation, overgrazing, and climate change. The authors caution that sample coverage estimates across grid cells varied, and that incomplete occurrence data may affect the robustness of some spatial patterns, so additional field surveys are warranted.

This study demonstrates the power of combining molecular phylogenetics with spatial analysis to reveal hidden evolutionary patterns that traditional species counts alone cannot detect. By distinguishing between areas where new species are evolving and areas where ancient lineages persist, the approach provides conservation planners with a more nuanced picture of biodiversity. Rather than simply protecting areas with the most species, planners can now target regions that harbor evolutionarily distinct lineages, ensuring that both the products of recent radiation and the survivors of deep evolutionary history are preserved for future generations. As climate change accelerates and habitats shrink, such phylogenetically informed conservation strategies may prove essential for safeguarding Kenya’s remarkable botanical heritage.

The research was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the Sino-Africa Joint Research Center, reflecting a growing international collaboration to document and conserve African plant diversity. The open access article, published on 19 October 2026 in BMC Plant Biology, includes supplementary materials with distribution data, newly sequenced taxa lists, the species-level phylogenetic tree, and robustness analyses of the CANAPE patterns, allowing other researchers to verify and build upon the findings. As Kenya continues to balance development with conservation, studies like this one provide the scientific foundation needed to make informed decisions about where to focus protection efforts, ensuring that the full spectrum of evolutionary history embedded in the country’s flora is not lost before it is even documented.

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

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

Article References: Katumo, D. M., Jiao, B., Wei, M., Niu, G., Wang, W., & Gao, T. (2026). Spatial patterns of phylogenetic diversity and neo- and paleo-endemism in Kenyan Asteraceae. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10210-8

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10210-8

Keywords: Spatial, patterns, phylogenetic, diversity, neo-, paleo-endemism, Kenyan, Asteraceae, scientific research