Ecological Assessment of Riparian Vegetation Diversity and Phytosociological Structure Along the Arpa River, Central India

Abstract

The present study assessed the floristic composition, phytosociological structure, diversity and conservation status of riparian vegetation along the Arpa River in Bilaspur district, Chhattisgarh, India during 2024–25 and 2025–26. The study was conducted along the selected river stretch from Seepat Chowk, Bilaspur, to Arpa Bridge, Belgahna, covering a total research area of approximately 62 km. The river stretch was classified into three disturbance zones based on anthropogenic pressure: Zone I, Highly Disturbed Urban Area; Zone II, Moderately Disturbed Semi-urban/Rural Area; and Zone III, Least Disturbed Forest/Remote Area. Vegetation sampling was conducted using simple random sampling, with ten 10 m × 10 m quadrats established in each zone, giving a total of 30 quadrats and a sampled area of 3000 m². A total of 46 plant species, comprising 32 tree species, 9 shrub species, and 5 herbaceous species, were recorded from the sampled riparian vegetation. The recorded flora represented 25 families based on the complete species inventory. Fabaceae was the most species-rich family, contributing 10 species, whereas Asteraceae contributed the highest number of individuals. The phytosociological assessment revealed considerable variation in frequency, density, basal area and Importance Value Index among species. Parthenium incanum recorded the highest IVI (14.96), followed by Parthenium hysterophorus (14.30), Ruellia tuberosa/Ruellia spp. (11.84), Ipomoea carnea (11.52) and Solanum nigrum (10.61), while Terminalia tomentosa recorded the highest IVI among the tree species (10.21) in the principal phytosociological dataset. All were significant at p < 0.05. The results reveal a species-rich but invasion-prone riparian corridor whose structural integrity depends strongly on the near-channel zone, providing a quantitative baseline for riparian management, invasive species control and biodiversity conservation in Central Indian river systems.