Diversity and Structural Assessment of Tree Species in Sacred Groves of Kodagu

Abstract

Aims: The present study was undertaken to assess the structure, diversity and regeneration status of tree species, with special emphasis on RET species, in the sacred groves of Kodagu representing evergreen and deciduous vegetation types. Study Design: A stratified random sampling approach was adopted. Place: The study was conducted in 19 sacred groves representing the semi-evergreen and moist deciduous vegetation types of Kodagu district, Karnataka, India. Methodology: A stratified random sampling design was adopted using 4 m-wide belt transects laid perpendicular to a baseline until 500 trees (GBH ≥10 cm) were recorded per sacred grove. Tree species, GBH, height, and basal area were documented for floristic analysis, including diversity and similarity indices. Regeneration was assessed in 4 × 4 m subplots at 25 m intervals. Differences in floristic attributes and regeneration between vegetation types and grove sizes were analysed using appropriate statistical tests. Results: The study revealed that semi-evergreen sacred groves supported greater overall tree species richness (143 species) and a higher diversity of rare, endangered, and threatened (RET) species than moist deciduous groves, although mean species richness and stand structural attributes were comparable between vegetation types. Larger groves consistently exhibited significantly greater tree density, basal area, species richness, and regeneration diversity than smaller groves, highlighting the importance of grove size in maintaining ecological integrity. An inverse J-shaped girth-class distribution indicated healthy regeneration and stable population structure. Semi-evergreen groves also supported higher RET regeneration, emphasising their critical role in long-term biodiversity conservation. Conclusion: Sacred groves in Kodagu effectively conserve tree diversity and support regeneration, with larger semi-evergreen groves supporting higher species richness, threatened taxa, and ecosystem resilience, underscoring their conservation importance.