Distribution and biodiversity of tropical saltmarshes: Tamil Nadu and Puducherry, Southeast coast of India

Saltmarshes are an important marginal coastal ecosystem influenced by tidal movement and are created by the interaction of the halophytic vegetation and sediment trapped from inundating water. This study gives the baseline information on saltmarsh distribution and diversity along the Southeast coast of India. Saltmarsh locations were identified and mapped using satellite images of 2010 of IRS P6 LISS III (23.5 m resolution) & LISS IV (5.8 m) and LandSAT 8 OLI (30.0 m resolution). A total of 37 saltmarsh vegetation sites were identified along Tamil Nadu and one in Puducherry Union Territory. Seven species of saltmarsh flora are reported under four genera and three families: Arthrocnemum indicum (Willd.) Moq., Salicornia brachiata (Roxb), Sesuvium portulacastrum (L.), Suaeda fruticosa (Forssk), S. maritima (L.) Dumort, S. monoica (Forssk) and S. nudiflora (Moquin). The maximum benthic coverage by the saltmarsh community observed at Arucottuthurai was 93.3% and a minimum percentage cover of 28% was observed at Pazhaiyar. The biodiversity indices calculated for all study sites displayed maximum saltmarsh diversity (Shannon-Wiener H’ = 2.295 ± 0.001) at Vedaranyam and a minimum diversity (H’ = 0.759 ± 0.001) at Thirukazhipalai. A total of 23 species representing 16 fauna and seven flora were observed as associates from the saltmarsh ecosystem. Saltmarsh ecosystem provides unique breeding sites for macro fauna and roosting ground for avifauna, provide livelihood options for coastal communities and protects the integrity of coast. Rapid coastal development and aquaculture pose a major threat to this ecosystem. This study helps to protect, conserve and sustainably use this ecologically important coastal ecosystem and prepare specific management strategies by stakeholders. •Saltmarsh ecosystem protect shorelines and helps to maintain the integrity of the coast.•First study on saltmarsh diversity and distribution in Tamil Nadu & Puducherry, India.•Mapping and delineation of saltmarsh ecosystem based on CRZ Notification 2011.•Study helps to protect, conserve and sustainable use of this ecologically sensitive area.•Supports preparation of specific management strategies by scientists and associated stakeholders.