Species diversity and community characteristics of understorey vegetation in a tropical moist deciduous forest of Assam, India

Abstract

The study presents a comprehensive assessment of species diversity and community characteristics of understorey vegetation in a tropical moist deciduous forest of Assam, India. An extensive field survey was conducted in the selected study site, i.e., Fatasil Reserve Forest (FRF), between 2022 and 2025, and the stratified random sampling method was employed. 300 quadrats of the size 25 m² and 600 quadrats of the size 1 m² were laid for shrubs and herbs, respectively. Thus, a total of 900 quadrats were used for the study. Total density and total basal cover (TBC) were reported as 1545 stem ha⁻¹ and 4.92 m² ha⁻¹, respectively, for shrubs; and 8861.11 stem ha⁻¹ and 0.58 m² ha⁻¹, respectively, for herbs. Based on the Importance Value Index (IVI), the most dominant shrub species were Lantana camara, Ocimum tenuiflorum, and Solanum torvum, and the most dominant herb species were Ageratum conyzoides, Leucas aspera, and Acmella paniculata. Moreover, shrub vegetation exhibited moderate diversity and richness, whereas herbaceous vegetation exhibited high diversity and richness in the study site. There was high species evenness of both shrub and herb vegetation, which reflects the uniform distribution of species, indicating stable understorey plant communities in the study site. However, the observed moderate diversity and richness of shrub vegetation raise concerns, underscoring the need for appropriate and well-planned management strategies aimed at habitat conservation and minimizing anthropogenic disturbances to ensure its long-term sustainability.