Floristic composition and diversity of Sindhanur Taluk, Raichur District, Karnataka, India

The present study documents the floristic composition and ecological diversity of Sindhanur Taluk, located in Raichur District, Karnataka, India, a region characterized by black cotton soils, a semi-arid climate, and extensive canal irrigation systems. Systematic field surveys were conducted during the monsoon and post-monsoon seasons, strategically timed to coincide with the active growth and flowering phases of most plant species. Using transect walks and quadrat sampling, data were collected across diverse microhabitats such as tank beds, agricultural margins, fallow lands, and dry scrublands, ensuring comprehensive representation of the vegetation. A total of 308 angiosperm plant species were recorded, representing a wide taxonomic range, with Fabaceae, Poaceae, Asteraceae, and Euphorbiaceae emerging as the dominant families. Quantitative analysis revealed considerable variation in density, abundance, and frequency. Species such as Striga asiatica (L.) O. Ktze. and Indigofera trifoliata L. exhibited high density, while Ricinus communis L. and Cleome gynandra L. showed remarkable abundance. High-frequency species included Carissa spinarum L., Sesamum indicum L., and Urochondra setulose (Trin.) C.E. Hubb., indicating their widespread occurrence and ecological dominance. Diversity indices further emphasized the ecological richness of the region. The Shannon–Weiner Diversity Index was recorded at 4.11, suggesting high species richness and evenness. The Simpson’s Diversity Index of 0.98 confirmed high heterogeneity, while the Species Diversity Index of 0.70 reflected moderately high overall biodiversity. These findings underscore the ecological significance of Sindhanur Taluk, where natural and semi-natural habitats coexist with agricultural landscapes, supporting a structurally complex and functionally diverse flora. The study not only provides a baseline for future ecological monitoring and conservation planning but also highlights the urgent need to preserve native plant diversity amidst increasing anthropogenic pressures in the region.