Floral inventory and habitat significance of riparian ecosystem along the banks of Chithari River, Kasaragod, Kerala, India

Abstract

The Chithari River, spanning approximately 25 km in Kasaragod District, Kerala, originates from lateritic midlands rather than mountains, forming a riparian landscape. This study conducted a comprehensive floristic survey of its riparian zones, covering four major tributaries—Pullur Thodu, Para Thodu, Cherkkappara Thodu, and Pakkam Thodu—using line transects, and nested plots between October 2024–February 2025. A total of 340 plant species, representing 257 genera, and 75 families, were documented. Fabaceae (61 species) emerged as the dominant family, followed by Rubiaceae (20 species), Euphorbiaceae (17 species), and Moraceae (16 species). The recorded flora included 181 tree species, 45 shrubs, 69 herbs, and 45 climbers. Of these, 281 species were native, while 59 were exotic, comprising 17% of the total flora. Invasive species such as Lantana camara, Chromolaena odorata, and Eichhornia crassipes were found to impact various habitats significantly. The study also identified 68 endemic species, including 24 species endemic to the Western Ghats. Nine species were categorized under conservation concern, including Crinum malabaricum (Critically Endangered), Pterocarpus santalinus (Endangered), and Strobilanthes ciliatus (Vulnerable). The restricted distribution of Crinum malabaricum in lateritic streambeds of the midlands highlight the need for targeted conservation measures.