Ecohydrological response of a tropical peatland to rainfall changes driven by Intertropical Convergence Zone variability

Aim
Tropical peatlands are globally significant carbon stores, increasingly threatened by human activities and climate change. However, their ecohydrological responses to shifting water availability remain poorly understood. In this study, we investigate the connections between climate change, hydrology and vegetation dynamics in a coastal tropical peatland in Panama, aiming to understand the effects of future drying on peatland dynamics.

Location
Bocas del Toro, Panama (9°22′54″N, 82°21′59″W).

Taxon
Angiosperms.

Methods
High-resolution multiproxy palaeoecological data, including pollen and plant macrofossils (vegetation), testate amoebae (water-table depth) and physical peat properties, are used to explore the relationships between climate change, hydrology and vegetation in a coastal tropical peatland over the past 700 years. Downscaled climate simulations are integrated with this process-based understanding to project the likely future responses of this coastal peatland to climate change.

Results
We identify a clear connection between precipitation variability, driven by shifts in the Intertropical Convergence Zone and water-table dynamics, which subsequently influence changes in the peatland vegetation mosaic. Historical drier periods are marked by the expansion of shrub communities into the open peatland plain.

Main Conclusions
Palaeoecological studies incorporating climate and hydrological proxies are essential for understanding both recent and future ecohydrological dynamics of tropical peatlands. Our findings suggest that in response to future climate change, water tables will lower and shrub communities will expand due to rising temperatures and reduced precipitation. Additionally, future sea-level rise, combined with declining rainfall, may result in seawater intrusion and significant vegetation shifts in coastal tropical peatlands.