Floristic Diversity and Ecological Structure of Coastal Sand Dunes of Tirunelveli District, Tamil Nadu, India
Sugaseelan Akash
Department of Plant Science, Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli - 627012, Tamil Nadu, India.
Velpandi Venkadeshraja
Department of Plant Science, Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli - 627012, Tamil Nadu, India.
Muthulingam Udayakumar *
Department of Plant Science, Manonmaniam Sundaranar University, Abishekapatti, Tirunelveli - 627012, Tamil Nadu, India.
*Author to whom correspondence should be addressed.
Abstract
Aims: Qualitative field survey was carried out to record flowering plant wealth of sand dunes and coastal areas of Tirunelveli district, one of the southern districts of Tamil Nadu, a part of peninsular India.
Study Design: Qualitative field survey.
Place and Duration of Study: Tirunelveli district of Tamil Nadu; One year.
Methodology: Qualitative field surveys were conducted to document flowering plant species occurring within approximately 100 m of the shoreline across coastal and sand dune habitats of Tirunelveli District, Tamil Nadu. The survey was carried out over a one-year period from April 2024 to March 2025. The study encompassed a 48.9 km stretch of coastline extending from Kootapuli to Thoppuvilai. Systematic field surveys were undertaken on foot along the coastal belt. Most plant species were identified on the site and recorded through detailed field notes. All identifications were further verified and authenticated by the research supervisor.
Results: A total of 253 plant species representing 182 genera and 61 families were recorded from the study area. Among these, Fabaceae was the most dominant family with 44 species, followed by Malvaceae (17 species), Acanthaceae and Euphorbiaceae (15 species each), Amaranthaceae, Convolvulaceae and Lamiaceae (12 species each), and Poaceae (10 species). Apocynaceae, Asteraceae and Phyllanthaceae were represented by eight species each, Portulacaceae and Rubiaceae by six species each, and Solanaceae by four species. In addition, nine families were represented by three species each, 11 families by two species each, and 27 families by a single species each. Herbs constituted the dominant life form with 108 species, followed by shrubs comprising 57 species that provide diverse microhabitats for dune-associated organisms. Trees were represented by 44 species and occurred in comparatively lower numbers, likely reflecting the combined effects of harsh environmental conditions, limited adaptive capacity, and anthropogenic pressures. Climbers accounted for 25 species and rely on structural support from surrounding vegetation, whereas creepers, represented by 19 species, contribute significantly to sand stabilization and surface binding.
Conclusion: The coastal sand dune ecosystem of Tirunelveli District supports relatively high floristic diversity, comprising 253 plant species across 182 genera and 61 families, including nine endemic taxa and several species of conservation concern. The dominance of herbaceous life forms and the substantial presence of invasive alien species reflect both strong adaptive strategies and increasing ecological stress within this fragile system.
Keywords: Coastal areas, conservation, invasive species, peninsular India, threatened species