Diversity, regeneration, and anthropogenic disturbance in major Indian Central Himalayan forest types: implications for conservation

Understanding community structure together with regeneration and disturbance provides a holistic purview of forest health and the necessary management implications essential for conservation. These aspects were studied independently or under specific elevational zone in Central Himalayas; therefore, this study was undertaken to understand the key relations and to access the status of major protected Central Himalayan forest types. The parameters were accessed using standard quadrat technique in eight major reserved and protected forest types along an elevational gradient (333-3375 m). Tropical moist deciduous forest had the highest stem density (457 tree ha(-1)), species richness (21 species), richness index (Margalef's index: 3.67) and diversity index (Shannon-Wiener index: 2.63). Quercus semecarpifolia-Rhododendron arboreum association forest had the highest total basal area (94.75 m(2) ha(-1)). Species predominantly showed clumped dispersion pattern. Climax Himalayan species viz. Shorea robusta, Quercus oblongata, and Abies spectabilis have poor regeneration which have modified the community into decreasing to unimodal distribution. Total basal area explained 71.9% (p < 0.001) of the total variation in species dominance. Species richness, diversity, and evenness indices showed strong significant positive correlations which are also evident in the species-sequence curves with species diverse sites having wider spread. Anthropogenic surface fires in sub-tropical Pine forest while grazing and lopping for fuelwood requirements in temperate and sub-alpine forests are major disturbance parameters. The results signify that these forests have not yet attained maximum diversity. Monitoring the regeneration of important native and climax species along with co-operation from local communities is key for efficient management of these forests.

Automated summary

By studying forest types and key relationships in protected areas of the Central Himalayas, it was found that tropical moist deciduous forests have the highest stem density and species richness, while Quercus semecarpifolia-Rhododendron arboreum association forests have the highest total basal area. The poor regeneration of climax Himalayan species has resulted in a decrease to unimodal distribution of species.