Functional Dominance of C3 Photosynthetic Pathways in an IUCN-Classified Urban Green Space: Evidence from a Tropical Institutional Landscape

Urban green spaces have an important role to play in addressing the impacts of climate change by means of reducing the amount of carbon dioxide (CO2) from the atmosphere, moderating urban heat islands, and increasing the capacity of ecosystems to deliver ecosystem services. Traits that are used by plants to function, notably photosynthetic pathways (C3 and C4), can greatly affect these functions. However, there is a large knowledge gap regarding the functional composition of managed urban ecosystems of the Global South. This study assessed the functional diversity of the plant species located within the campus of Vignan's Institute of Information Technology in India, with a particular emphasis placed on determining how photosynthesis affects the ability of those species to sequester CO2 as well as mitigate urban heat and reduce water consumption while providing ecosystem services. Species were initially categorized at the family level using International Union for Conservation of Nature (IUCN)-aligned Angiosperm Phylogeny Group (APG) IV classifications. They were then additionally categorized according to their photosynthetic pathway type (i.e., C3 or C4). The results show a large predominance of C3 species among all taxonomic groups evaluated with none of the species being assigned to C4 classification. The prevalence of C3 tree species indicates a higher capacity for storing carbon and for providing multi-functional ecosystem services. These findings highlight the need for incorporating a functional trait-based approach into urban green space planning and also provide evidence-based recommendations for developing climate-resilient landscaping practices within institutional landscapes found in tropical regions.