Phytosociological attributes of high-elevation agroforestry systems in the Western Ghat regions of Kerala, India

The diversity of tree species within agroforestry systems (AFS) plays a critical role in enhancing ecosystem services while fostering resilience and adaptability to environmental changes. Though plant diversity in the forests of Western Ghats is widely studied, research on the compositional and phytosociological characteristics of agroforestry systems remains underexplored. This study aims to assess the diversity and distribution of tree species in AFS to guide conservation strategies and sustainable management practices in Kerala’s Western Ghats. A total of 116 quadrates were established randomly and the species richness, stand density, diversity, dominance and other phytosociological attributes were measured. The study recorded 119 tree species with an average stand density of 1099 trees per hectare. The Shannon diversity index indicated relatively high species diversity (3.26), while the Simpson index suggested low dominance (0.08) across the study area. Pielou’s evenness index indicated moderate evenness in species distribution (0.68). Among different types of AFS, coffee-based systems exhibited the highest species richness, followed by cardamom, homegarden, rubber, and tea. Dominant tree species varied across different systems with Artocarpus heterophyllus, Grevillea robusta, Hevea brasiliensis, Mangifera indica and Erythrina variegata being the top species in the AFS in general. This study highlights the importance of conserving and managing the diverse AFS in the highland regions of the Western Ghats, a previously underrepresented area in biodiversity assessments, by demonstrating that variations in species composition underscore the unique characteristics of each system, with phytosociological studies playing a crucial role in conservation planning.