Reducing soil moisture under rising land-surface temperature is one key driver of the positive terrestrial feedback to climate change. Climate models commonly project widespread decreases in soil moisture under future climate warming on the global scale. However, direct observational evidence for such effect is still lacking, especially in wetlands. Here, we conducted a manipulative experiment to investigate the effect of warming on soil moisture in a coastal wetland.
Results/Conclusions
We found that warming increased the soil moisture content by 38.6%, 30.8% and 46.3% in 2015, 2016 and 2017, respectively. The coastal wetland has shallow groundwater level (0.50-2.50m). During the non-growing season, warming increased soil moisture through accelerating soil evaporation. During growing season, warming stimulated the soil moisture through improving root water uptake ability because warming enhanced root biomass and leaf transpiration. Our results indicate that the reduced soil moisture under climate warming would not happen in coastal wetlands. A better understanding of climate impacts on coastal wetland needs to take consideration of the interactions between biological and hydrological processes.