Effects of Continuous Periodic Phragmites Harvesting on Microbial Characteristics and Soil Multifunctionality in Wetlands Adjacent to Residential and Agricultural Areas

Abstract

This study investigated the mechanisms underlying the response of soil microbial communities and multifunctionality to continuous harvesting (HP) and nonharvesting (IP) treatments in Phragmites-dominated wetlands adjacent to residential and agricultural areas. Alpha and beta diversity analyses revealed that the microbial community evenness was significantly increased in the HP group. NMDS analysis revealed a highly significant difference in community structure between the HP and IP groups (P = 0.001), with the HP group exhibiting homogenized characteristics. At the phylum level, HP showed significantly greater abundances of Chloroflexi, Acidobacteriota, and Firmicutes, whereas Proteobacteria and Gemmatimonadota were enriched in IP. The microbial assembly in HP was mainly influenced by homogeneous selection (HoS, 27.31%) and dispersal limitation (DL, 37.98%). In IP, drift (DR, 34.56%) was the main factor. Functional prediction showed nitrate reduction increased in HP (P = 0.003), with reduced abundances of phototrophic taxa and a metabolic shift toward chemoheterotrophic strategies. Soil physicochemical analyses demonstrated significant reductions in the total nitrogen (TN) content and C/N ratio-mediated regulation of keystone taxa. The soil multifunctionality index (SMF) was higher in HP and linked to chemoheterotrophic functions and C/N metabolic pathways. These results elucidate how continuous periodic harvesting improves wetland soil functions by balancing carbon-nitrogen dynamics and microbial activity, providing insights for sustainable functional wetland management.

Keywords: Phragmites-dominated wetland, Continuous harvesting, Microorganisms, Carbon-nitrogen metabolism, Soil multifunctionality