Variation in floristic composition and dry matter dynamics of semi-natural temperate grassland ecosystem in Kumaun Himalaya

Semi-natural grasslands are species-rich ecosystems shaped by traditional, low-intensity land use, often originating from forest degradation or clearance and sustained through ongoing human management. In the Kumaun Himalayan region, grasslands below 3000 m elevation are largely a result of forest degradation and remain relatively unexplored. This study aimed to assess plant diversity and seasonal variation in dry matter dynamics in such ecosystems. A grassland site in Nainital district, Kumaun Himalaya, was selected, where three permanent plots (20 m × 20 m) were established. Monthly sampling was conducted for one year using 1 m × 1 m quadrats to analyze ecological parameters including species richness, density, total basal area, diversity indices (Shannon’s, Simpson’s, evenness), and biomass compartments (live, dead, litter, root biomass) following standard phytosociological methods. A total of 37 species across 17 families were recorded, with 12 families being monotypic. Species density ranged from 25.05 ind m⁻² (January) to 975.27 ind m⁻², and total basal area varied from 0.26 cm² m⁻² (January) to 54.40 cm² m⁻² (September). Shannon’s diversity peaked in April (1.79), while the Simpson’s index was highest in June (0.65). Biomass compartments ranged as follows: live biomass (2.67–336.83 g m⁻²), dead biomass (22.21–190.73 g m⁻²), litter (6.45–33.75 g m⁻²), and root biomass (175.12–368.88 g m⁻²). All parameters showed significant seasonal variation (p < 0.05). Aboveground and belowground primary production was 346.71 and 317.71 g m⁻², respectively. These findings highlight the seasonal dynamics, productivity, and ecological characteristics of the studied semi-natural grassland and provide baseline site-level information that can support future comparative and multi-site studies aimed at understanding grassland ecosystem functioning and management in degraded landscapes of the Kumaun Himalaya.