Wetland Type Matters: Tree Community Structure and Carbon Sequestration Dynamics Along a Tropical River Basin

[Geoengineering News]

https://link.springer.com/article/10.1007/s00267-026-02496-z

Authors: Samim Borbhuyan, Nirjhar Das, Kasturi Chakraborty, Kamini Kanta Sarma, Dibyendu Adhikari & Tapati Das 

19 June 2026

Abstract

Wetlands are among the most productive and ecologically significant ecosystems on the earth, offering a broad spectrum of ecosystem services including water purification, flood regulation, habitat provision, and climate regulation. In light of current global climate challenges, their capacity for carbon storage has become increasingly important, positioning wetlands as key components in climate change mitigation strategies. This study attempts a comprehensive understanding of the contributions of different types of tropical wetlands to ecological diversity and carbon dynamics. The findings of this study aim to inform climate action, support conservation planning, and strengthen local livelihoods. In the longer term, the study underscores the importance of tropical wetlands in regional and global carbon cycling, with clear relevance for wetland conservation and climate policy. For this study, we selected three morphologically and hydrologically distinct wetlands, namely, Fulbari Anua (oxbow lake, OL), Bakri Haor (floodplain wetland, FPW), and Sone Beel (perennial wetland, PW) in the Barak basin of Assam, northeast India, within the Indo-Burma biodiversity hotspot. Tree individuals were randomly sampled from both the aquatic zone (permanently inundated areas) and the riparian zone (seasonally flooded margins) of the selected wetlands. Comparison of the tree community composition across different wetland types revealed a total of 30 tree species representing 18 families. Wetland tree composition was more similar between permanent wetland (PW) and floodplain wetland (FPW) than between either of these and oxbow lake (OL). Maximum tree diversity was found in FPW (3.07) followed by PW (2.94) and OL (2.45), while the tree density was maximum in FPW (42 trees ha⁻¹) followed by OL (36 trees ha⁻¹) and PW (28 trees ha⁻¹). Above-ground biomass carbon was highest in FPW (168.99 Mg ha−1) followed by PW (147.48 Mg ha−1) and OL (106.57 Mg ha−1). Wetland trees in PW and FPW showed more similar carbon stock pattern than those in OL. Amongst the diverse tree species, Terminalia arjuna followed by Aegle marmelos had greater carbon stock in FPW; Tamarindus indica followed by Bombax ceiba had greater carbon stock in PW; while Bombax ceiba followed by Cocos nucifera had greater carbon stock in OL. The study showed that wetland tree carbon stock is driven more by basal area and species diversity than by tree density alone. Thus, in wetlands stand structure and composition appear to be more important determinants of carbon storage than stem number. The study highlights that tree-dominated wetlands in the tropical regions like the Barak River Basin are major carbon sinks that sequester atmospheric carbon, and thereby contribute to regional carbon sink capacity and the global carbon balance. The contribution of invasive trees to carbon stock was highest in PW followed by FPW and lowest in OL. Although the current carbon stock contribution from invasive trees is minimal, failure to control their spread could eventually lead to ecological imbalance, threatening the long-term resilience and functionality of wetlands. The study therefore suggests integrating nature-based solutions with adaptive management to enhance wetland biodiversity conservation, strengthen native carbon sequestration capacity, and ensure the long-term sustainability of tropical wetland ecosystems in the Barak Basin and beyond.

Source: Springer Nature Link