Does Marsh Restoration Have an Impact on Dew?

Abstract

As an ecological factor of wetland ecosystems, dew condenses frequently and in large amounts. In the process of marsh wetland restoration, the differences in water depth and plant types in different restoration years may affect dew condensation and evaporation. In this study, by monitoring dew in natural marshes, unrestored marshes (farmlands), and marshes restored 15, 10, and 5 years ago in the plant growth period of 2022 in the Sanjiang Plain, China, it was found that the “cold and wet effect” of marshes was conducive to dew condensation and could prolong the evaporation time of dew. In the process of marsh restoration, the number of dew days increased from 106 days (farmland) to 122 days (15-year marsh restoration), and the duration increased from 791.1 ± 90.3 min (farmland) to 869.4 ± 100.5 min (15-year marsh restoration). The dew intensity increased from 0.06 ± 0.02 mm (farmland) to 0.13 ± 0.04 mm (15-year marsh restoration), and the annual dew amount increased from 35.10 mm/y (farmland) to 44.86 mm/y (15-year marsh restoration). The number of dew days and the duration were similar to those of natural marshes after 15 years of restoration. SO42−, Ca2+, NH4+ and NO3− were the main ions of dew in marsh in each restoration year and farmland. There was no significant difference in the ion concentration (Ca2+, Mg2+, Na+, K+, NH4+, F−, Cl−, NO2−, and SO42−) of natural marsh dew compared with that 15 years after restoration (p > 0.05), except for NO3−. The marsh restored after 15 years had basically restored the characteristics of natural marsh in terms of the quality and quantity of dew. This study showed that marsh restoration increased dew, and dew was a good indicator of the restoration effect of marshes.