Floristic Composition and Community Dynamics of Gebar Grassland in Bhavnagar District, Gujarat, India

Abstract

Semi-arid grasslands are among the most ecologically significant yet understudied biomes of the Indian subcontinent, providing critical ecosystem services including carbon sequestration, soil stabilisation, and biodiversity support. This study presents a comprehensive three-year phytosociological assessment of the Gebar semi-arid grassland, Bhavnagar District, Gujarat, conducted across three ecologically distinct seasons Summer (pre-monsoon), Monsoon (rainy season), and Winter (post-monsoon), spanning 2023 to 2025. Using a spatially explicit 500 m × 500 m grid-based sampling framework implemented in QGIS, vegetation data were collected from 175 quadrat visits (1 m × 1 m, 5 grids × 5 quadrats × 7 season-year combinations), covering Winter 2023 and all three seasons of 2024 and 2025. A total of 23 plant species and 971 individual plant records were documented, dominated by the family Poaceae. Species richness ranged from S = 6 (Summer 2025) to S = 13 (Winter 2023 and Monsoon 2025). Shannon–Wiener diversity (H′) ranged from 1.507 to 2.210, with Monsoon seasons consistently yielding the highest values. Sehima sulcata (Hack.) A.Camus was the overwhelmingly dominant species (IVI = 50.59), nearly double the second-ranked Apluda mutica L. (IVI = 27.59). Whittaker's inter-seasonal beta diversity was high in both fully sampled years (βw = 0.966 in 2024, βw = 0.929 in 2025). NMDS ordination (stress = 0.146) and hierarchical cluster analysis confirmed season as the primary driver of community compositional variation. These findings establish a quantitative phytosociological baseline for this under-documented grassland and demonstrate the critical importance of multi-season monitoring for accurate biodiversity assessment of semi-arid ecosystems.