Functional Trait and Phylogenetic Diversity of Tree and Shrub Species in Three Tropical Forests across Anambra State, Nigeria

Abstract

Understanding which species coexist, their roles, and interactions enrich our knowledge of local ecosystems; and, the ecosystem services rendered by forests are paramount. Identifying key tree species allows us to assess their contributions to ecosystem services such as carbon sequestration, soil stability, and habitat provision. This research examined the functional trait and phylogenetic diversity of tree and shrub species in three tropical forests in Anambra State. A combination of line transects and plot sampling was used in this study. Field inventory of tree flora was undertaken to collect data. At each location, six plots of 10 m × 10 m each were randomly demarcated using a line cut and the trees within the plots were assessed. The identification and recording of different tree species was carried out according to the Linnaeus taxonomy of species classification. Functional leaf characteristics (dry mass, size and specific area) were recorded for at least two healthy, unshaded adults of the different species. Phylogenetic diversity was determined by constructing phylogenetic trees. All data analysis for this study was performed using the Python programming language. The Statistical Package for Product and Services was used to provide supplementary analyzes such as dendrogram plotting. The metrics of functional diversity, including Rao's squared entropy (Rao's Q), functional richness, functional evenness and functional divergence, for the three plant communities were also presented. Phylogenetic representation of all tree and shrub species included in the analysis of NACF, IFU and UFA, based on species abundance data, revealed several distinct clusters within the dendrogram and some close clusters, indicating close relationships between species in the dendrogram dense cluster. There were also intermediate and distant clusters that showed moderate similarities and differences in relationships, respectively. Overall, the diversity of functional traits examined in this study provides valuable insights into ecosystem functioning. This will be helpful to researchers, and other stakeholders can use this information to model carbon sequestration, nutrient cycling, and other ecosystem services.