Mangroves of Kadalundi-Vallikunnu Community Reserve: A Study on Carbon Sequestration and Biodiversity Indices

Mangrove ecosystems are vital blue carbon sinks that contribute significantly to climate change mitigation by capturing and storing atmospheric CO₂ in their biomass and soils. This study assessed the phytosociology and carbon sequestration potential of the Kadalundi-Vallikunnu Community Reserve (KVCR) in Kerala, India, focusing on the aboveground, belowground, and soil carbon pools within its mangrove ecosystems. Using a stratified transect sampling approach across five key sites, we documented eight true mangrove species, with Avicennia officinalis as the dominant species, contributing 40.71% to the ecosystem’s relative density and 65.73% to basal area. Biodiversity indices indicated a balanced community with moderate diversity, characterized by a Shannon-Wiener Index of 1.648 and a Simpson Index of 0.753. The total aboveground and belowground biomass was calculated at 150 ± 18 t/ha, translating to a biomass carbon stock of 75 ± 9 t C/ha. Soil carbon stocks, estimated to a depth of 70 ± 10cm, averaged 145 ± 12 t C/ha, with soil carbon constituting 66% of the total ecosystem carbon stock. A positive correlation (r = 0.81, P< 0.01) between soil bulk density and carbon content in the upper layers was observed, underlining the stability of carbon in mature mangrove soils. The total ecosystem carbon stock of KVCR was estimated at 220 ± 25 t C/ha, a value comparable to mature mangrove ecosystems in other tropical regions. Comparative analysis with studies in Saudi Arabia’s Red Sea and the Arabian Gulf highlights that Kerala’s tropical conditions support higher carbon sequestration, reinforcing the importance of KVCR in regional and global climate mitigation. These findings highlight the need for conserving mangroves in KVCR, considering their potential in removing carbon from the atmosphere, along with other biodiversity-supporting roles that contribute to both regional climate resilience and global carbon reduction targets.