Diversity, species richness and vegetation pattern in the major forests of Tehri Garhwal, Western Himalaya
摘要
Himalayan forests represent one of the most fragile yet ecologically significant ecosystems, playing a vital role in maintaining regional and global biodiversity. The present study assessed species diversity, richness, and vegetation structure across different forest types in the Tehri Garhwal district of Western Himalaya following the standard methods. A total of 344 plant species belonging to 82 families and 146 genera were recorded, with herbs contributing the highest proportion (62%), followed by shrubs (23%) and trees (15%). Among families, Asteraceae, Rosaceae, Lamiaceae, and Fabaceae emerged as dominant contributors. Species richness varied across forest types, with maximum richness in mid elevational forests, largely shaped by anthropogenic interventions and grazing pressure, while high-elevational forests exhibited lower richness. Tree density ranged from 560–770 ha⁻1 and basal area from 45.93–80.93 m2 ha⁻1, values that are consistent with those reported in previous studies conducted in the Himalayan region. Diversity indices revealed that the herbaceous layer exhibited higher Shannon diversity compared to shrubs and trees, highlighting its importance in sustaining overall community diversity. Distribution patterns were predominantly contagious in trees and herbs, while shrubs showed random patterns in certain forest types. Regression and correlation analyses indicated strong positive relationships between density, species richness, and heterogeneity, underscoring the role of structural attributes in regulating ecosystem stability. This study provides baseline information on species composition and forest structure of Himalayan pure forest types, offering critical insights for biodiversity conservation, ecological monitoring, and sustainable forest management.