Floristic Diversity of Angiosperms in Sand Dunes and Coastal Areas of Viluppuram District, Tamil Nadu, India

A qualitative field survey was conducted to document vegetation in sand dune and coastal areas of Viluppuram District, situated along the Coromandel Coast of Tamil Nadu, which represent ecologically significant ecosystems that support diverse plant communities adapted to harsh environmental conditions. A comprehensive floristic survey was conducted between January 2025 and March 2026. A total of 268 angiosperm species distributed among 219 genera and 75 families were documented. Fabaceae emerged as the most species-rich family with 35 species, followed by Malvaceae (15 species), Convolvulaceae and Poaceae (12 species each), Apocynaceae (11 species), and Acanthaceae, Amaranthaceae, and Euphorbiaceae (10 species each). Life-form analysis showed a predominance of herbs (106 species), followed by trees (70 species), shrubs (45 species), climbers (32 species), and creepers (15 species). Assessment of plant functional types revealed phanerophytes as the dominant group (158 species), while therophytes (51 species), graminoids (22 species), legumes (15 species), succulents (12 species), geophytes (6 species), parasites (3 species), and carnivorous plants accounted for 1 species. The study further recorded six endemic taxa, namely Mussaenda tomentosa, Chloris wightiana, Lepidagathis pungens, Commiphora berryi, Euphorbia glaucescens, and Hardwickia binata, highlighting the conservation value of the region. The conservation status revealed two Vulnerable species, one Near Threatened species, 116 species of Least Concern, and five Data Deficient species. The floristic richness observed in the present study exceeds that reported from several other coastal dune ecosystems of Tamil Nadu, underscoring the importance of Viluppuram as a reservoir of coastal biodiversity. However, increasing anthropogenic disturbances, including fuelwood collection, waste disposal, and habitat degradation, pose substantial threats to these ecosystems. The findings emphasise the urgent need for conservation planning, habitat protection, and long-term ecological studies to safeguard the biological integrity and ecological functions of the coastal dune landscapes of Viluppuram District.