Unveiling the ecological wealth: Species diversity, conservation impact, and carbon sequestration in mangrove ecosystems

Abstract

Mangroves are one of the most productive ecosystems in the world. However, mangroves are considered as sensitive ecosystems, which are vulnerable to diverse array of anthropogenic and natural disturbances. Hence, acknowledging the dynamics of mangrove vegetation in different environmental conditions is a timely need for sustainable conservation of mangroves. Consequently, we conducted this study to assess the species composition, structural characteristics, biomass, and carbon stock of mangrove species in Kandakuliya, Kalpitiya. We selected three sites using complete random block design sampling, from each mangrove patch, a 10 m x 10 m sample plots were established. The study was conducted between June 2023 to October 2023 with monthly sampling. We found eight species of mangroves among sites and the highest total abundance was recorded at site 2 (46 individuals). In terms of species composition, majority of individuals (54) belonged to Pemphis acidula species. According to diversity indices, the highest Shannon-Wiener's diversity index (H′) value was recorded in site 1 (1.68), and the highest Pielou's evenness index (J) (0.93) and the highest Simpson's index of diversity (0.82) were also recorded in site 1. As per the biomass analysis, the total biomass value was 355.3 Mg/ha, with 199.01 Mg/ha above-ground and 156.29 Mg/ha below-ground. Further, study showed that the total carbon stock ranged from 1.38 to 43.96 Mg C/ha among the recorded eight mangrove species. The highest importance value index was observed in the P. acidula species, occupying 45.11 % of the total population. Notably, Avicennia marina (43.96 Mg C/ha) and Excoecaria agallocha (39.74 Mg C/ha) were exhibited substantial carbon storage capacity. The CO₂ equivalent of the ecosystem carbon stock (16.67 t CO₂e) indicates that, despite high levels of anthropogenic activities leading to fragmented distribution, these ecosystems remain effective in long-term carbon sequestration, provided they are not further disturbed. This study findings demonstrates that the area can store significant amounts of carbon, emphasizing the importance of sustainable management and conservation to enhance its capacity for climate change mitigation.