Composition, structure and productivity of the herbaceous vegetation of five forest stands varying in soil moisture and nitrogen in Central Himalaya, India

Abstract

Herb layer contributes significantly to the species diversity of forest ecosystem and reacts rapidly to changes in the soil characteristics. Composition, structural parameters and productivity of the herbaceous vegetation of five forest stands in the Central Himalaya of India, situated at Nainital district of Uttarakhand, India were investigated. At each site, 1 ha plot was established and herbaceous vegetation was analysed by placing 30 random quadrats of 50x50 cm at each site. To determine the soil moisture and soil nitrogen, soil samples were collected from each site and analysed in the laboratory. Results showed that chosen sites contrasted in terms of soil moisture, total soil nitrogen, herbaceous diversity, and biomass. In this study, 70 genera, 73 species from 31 families of herbs were recorded. Total number of herbaceous species recorded in the stands varied from 28 (Pines and Hanumangarhi) to 50 (Takula).Total individuals of all herb species were 110, 114,141, 164 and 188 plants m -2 in Rusi (RU), Hanumangarhi (HG), Pines (PI), Barapatthar (BP) and Takula (TA) forest stands, respectively. Index of similarity and species turnover ranged from 34.48 to 62.50 and 0.31 to 0.54 respectively. Herb density, diversity and biomass showed positive correlation with soil moisture and soil nitrogen. These findings suggested that the soil moisture and nitrogen enhanced the herbaceous diversity by ameliorating soil conditions. Herb species such as Bidens pilosa, Commelina benghalensis, Erigeron kavinskianus, Eupatorium adenophorum, Micromeria biflora, Oplismenus compositus, Oxalis corniculata, Strobilanthes angustifrons, Viola canescens, Vitis himalayana were most benefitted species because they were present across all the forest stands in high density where as herb species like Ajuga bracteosa, Anemone vitifolia, Arisaema tortuosum, Cassia occidentalis, Craniotome furcata, Dioscorea bupleuroides, Lepidagathis cristata, Sigesbeckia orientalis, Veronica beccabunga and Vicia villosa were the most affected species because they were recorded from among one of the forest stand and they are present in very low density. This study also demonstrated a straight relationship between herbaceous diversity and biomass indicating the significance of species diversity for ample generation of biomass in forest ecosystem.