Water table drawdown increases plant biodiversity and soil polyphenol in the Zoige Plateau

Abstract

Water table drawdown accelerates peatland degradation and carbon loss from peatland, but phenolic compounds—the concentration and composition of which are determined by vegetation community composition—can slow down carbon loss. However, the response of phenolic compounds to water table drawdown is not clear. We aimed to clarify how water table drawdown influence soil phenolic compounds composition by detecting them at peatlands with different water table. Our results showed that water table drawdown changed plant biodiversity and altered the structure of phenolic compounds. Plant biodiversity, richness, evenness, areal coverage, and aboveground biomass all significantly increased with the water table drawdown. Phenolic compounds transferred from monophenol to polyphenol with the water table drawdown. The concentration of water-soluble phenols also increased with the water table drawdown due to the hydrophilic nature of polyphenol compounds. In addition, the concentration of water-soluble phenols was positively correlated with total vegetation coverage and richness. We concluded that water table drawdown accelerates change in the vegetation community, alters the structure of phenolic compounds and increased the concentration of water-soluble phenols, which could play an important role in carbon output from peatlands.