Precipitation and water table dynamics in peat swamp catchment in Sarawak, Malaysia

Globally, peatland covers 3% of the land area, with significant concentrations in tropical regions. In Malaysia, Sarawak alone accounts for 70% (1.6 Mha) of the country's peatland. Tropical peatland is characterized by waterlogged conditions that promote the accumulation of organic matter (peat) from decaying plant material. These conditions strongly influence vegetation, species composition, peat type, and carbon release, making them crucial for climate change mitigation. The hydrology of tropical peatland is primarily influenced by the fluctuation of the water table (WT) depth in its catchment. This study analyzes five years (2011-2015) of field measurements on WT and precipitation (PT) dynamics, observing their trends. PT was found to significantly regulate monthly WT at the study site (p < 0.01), showing a positive correlation. However, PT exhibited a downward trend over the study period, although not significantly for all sites. Similarly, WT at MA, MC, and MD did not show significant trends, likely due to ENSO events from 2011 to 2015. In contrast, MB experienced a significant decrease in WT, possibly caused by a nearby river acting as a drain and accelerating WT lowering.