Overview of My Research
I am interested in investigating the ecological and evolutionary mechanisms that generate and maintain biodiversity and how plants respond to environmental changes. Biodiversity has different forms including genetic, phylogenetic, functional, taxonomic, and ecosystem levels. Thus, I integrate datasets across these biodiversity levels to answer research questions relating to the diversification, distribution, and diversity of plants across multiple spatial and temporal scales. These dataset originate from field observations and experiments, herbarium, and laboratory methods. I am currently working in Africa (Nigeria, Cameroon, and Rwanda), North America, and the Mediterranean Basin. I strive to use my research to solve real world problems, therefore my research studies have significant applications in national and international conservation practices and policies.
Here are the links to my GITHUB repository and open access research data.
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My research themes include:
Community ecology and phylogenetics
Biogeography
Invasion biology
Species distribution modeling
Conservation genetics
Indigenous knowledge systems
African plant biogeography
Genomic data sequenced from voucher specimens collected from ongoing floristic surveys in West Africa will be combined with existing phylogenetic, functional, and geospatial data to answer fundamental questions about the drivers of biodiversity patterns in the tropical rainforest and Africa, more broadly: (1) Is there significant concentrations of neo- and paleo-endemic plants in the tropical rainforest compared to other biomes on the continent? (2) Are functional trait divergence and diversity associated with speciation rates of African flora? At regional scales, we will examine the role of tropical montane and riparian areas as refugia during Pleistocene glaciation, and testing the riverine barrier hypothesis, we will investigate how ecological and landscape features facilitate allopatric speciation and net diversification of plants in the Cross-Sanaga region.
Spatial phylogenetics
At the core of spatial phylogenetic studies is the estimation of phylogenetic diversity (PD; the sum of branch lengths on a phylogeny connecting the species in a location), and phylogenetic endemism (PE, like PD except emphasizing branches with small ranges) which can be measured on phylograms, cladograms, or chronograms (three different representations of branch lengths on phylogenetic tree as discussed above) representing three different facets of phylodiversity (Kling et al. 2018). With collaborators at University of California Berkeley, University of New South Wales, Australia, and University of Florida, Gainesville, I am mapping the phylodiversity of North America using about 10 million occurrence data and modeled ranges of about 12,000 native seed plants. Key results will include centers of endemism (neo, paleo, and mixed endemisms), phylogenetic turnover, and concentrations of significantly low and high phylogenetic diversity. These phylogeographic patterns will be overlaid with maps of protected areas for conservation congruence and future planning. Similar study is also being conducted using the native Africa flora.​[Image taken from Earl et al. (2021)]
Temporal shifts in plant communities
Correlative and mechanistic models have been used widely to predict future niche and range shifts in plants and animals. Broadly, it is predicted that many species will move to higher latitudes and elevations due to climate change. However, empirical studies do not support this widely accepted hypothesis. This is may be partly due to lack of consideration for the species' fundamental niches. The ecological resilience of plant communities can be reliably assessed by temporal monitoring of community dynamics, species composition and abundance changes. I am currently investigating community shifts and temporal beta diversity in many ecoregions in the United States to assess their vulnerability to regional and global climatic changes.
Biogeography of invasion
Invasive species are one of the main threats to biodiversity. Yet, species accumulation curves predict that there are opportunities for more species to be introduced and successfully invade new areas. My research on invasive species include (1) modeling the potential distribution of invasive plants in Africa and the Mediterranean Basin, (2) assesing the degree of niche overlap, similarity, and stability between the native and invaded ranges of invasive species across Africa and North America, (3) investigating the role of evolutionary relationship between native plant communities and the invasive species in facilitating invasion success, and (4) studing the relationship between niche overlap and population genetic/genomic diversity between native and invaded ranges of invasive species.
Ethnobiology, ecosystem services, and Indigenous Knowledge
For many generations, humans have depended on plants for basic livelihood such as food, medicine and shelter. However, the transmission of ethnobotanical knowledge is complex over time and space. I am interested in the diffusion of traditional ecological and ethnobotanical knowledge across cultural and geographical dimensions. Furthermore, I work with anthropologists to document the biodiversity of sacred forests in African tropical ecosystems to assess the conservation value of these sacred natural sites.