Distribution and environmental drivers of multi-functional community traits in the Sundarbans mangrove forest

Abstract

Mangrove forests are vital blue-carbon ecosystems, playing a crucial role in global carbon storage, climate regulation, and biodiversity conservation. However, escalating environmental threats, particularly salinity intrusion, necessitate a deeper understanding of their functional dynamics to inform effective conservation and restoration strategies. This study examines the distribution of multi-functional community traits (MFCT) and their environmental drivers across mangrove functional groups (pioneer, mid-successional, climax) along salinity gradients in the Sundarbans, the worlds largest mangrove forest. Using data from 62 plots, nine functional traits from 17 mangrove species were analysed to evaluate MFCT diversity and its environmental determinants. Results revealed distinct variations in MFCT diversity, with mid-successional species exhibiting the highest trait diversity (64.0 {+/-} 1.58), followed by climax (51.3 {+/-} 2.09) and pioneer groups (50.2 {+/-} 2.26). Climax species demonstrated resilience to salinity increases (R{superscript 2} = 0.29, p < 0.001), whereas mid-successional and pioneer groups were negatively affected (R{superscript 2} = 0.22, p < 0.001 and R{superscript 2} = 0.17, p < 0.001). Annual precipitation exerted contrasting effects, reducing diversity in climax species (R{superscript 2} = 0.25, p < 0.001) but enhancing it in mid-successional (R{superscript 2} = 0.22, p < 0.001) and pioneer groups (R{superscript 2} = 0.06, p = 0.05). Notably, MFCT values remained stable across salinity gradients, underscoring the ecosystems functional resilience. These findings highlight mid-successional species as keystones in sustaining mangrove multifunctionality and resilience under environmental stressors. Prioritizing these species in conservation and restoration efforts can mitigate the impacts of salinity intrusion and climate variability. By integrating the MFCT framework, resource managers can develop targeted restoration strategies to enhance ecosystem functionality and long-term stability. These insights provide a critical foundation for policymakers to align global mangrove conservation with adaptive management strategies, reinforcing coastal resilience, biodiversity conservation, and climate change mitigation.