The Paradox of Carbon Sequestration in Tropical Wetlands: High Contributions from Invasive Species Demand Control and...

Tropical wetlands provide critical services, including carbon sequestration and biodiversity conservation. This study assesses the community composition, species diversity, and carbon stock potential of aquatic vegetation across three distinct wetland types in Barak Valley, Assam, Northeast India, namely an oxbow lake (OL), a floodplain wetland (FPW), and a perennial wetland (PW). Field surveys were conducted during the wet and dry seasons, with vegetation sampled across both aquatic and riparian zones using a randomized quadrat approach. Data on species composition, density, and biomass were collected, and phytosociological analyses was done to evaluate community structure and diversity of the wetland vegetation. Carbon stock was estimated from dry biomass, using a conversion factor to quantify carbon content. The study identified 53 plant species across the wetlands, with PW exhibiting the highest species richness (42 species) and OL the highest carbon stock (2.76 Mg ha⁻¹). Invasive plants contributed approximately 50-60% to the total carbon stock, suggesting a significant but ecologically complex role in carbon sequestration. A moderately strong positive association (R² = 0.65) was observed between plant diversity and carbon stocks although invasive dominance weakened evenness and possibly the community resilience. While invasive species significantly enhance carbon storage, their ecological impacts on native biodiversity and resource allocation raise concerns about ecosystem health and resilience. These findings highlight the need for adaptive wetland management strategies that balance carbon sequestration with biodiversity conservation, particularly through the control of invasive species.