The Introduction of Woody Plants for Freshwater Wetland Restoration Alters the Archaeal Community Structure in Soil

Due to the severe degradation of wetland ecosystems in China, great efforts, such as the reconstruction of forested wetlands, have been devoted to restore the damaged and degraded wetlands to support species diversity and ecosystem services. However, less attention has been given to the diversity and ecological significance of prokaryotes of the domain Archaea compared with prokaryotes of the domain Bacteria during the reconstruction of forested wetlands. Here, the effects of introduced woody plants (Taxodium distichum and Alnus trabeculosa ) on the archaeal community in a freshwater wetland in the Yangtze estuary were investigated. The results showed that Thaumarchaeota obviously predominated at three studied sites in the freshwater wetland, the relative abundance of which decreased with increasing depth, ranging from 93.9% (0–10 cm) to 1.9% (30–40 cm) in mudflats, from 100% (0–10 cm) to 64.8% (30–40 cm) in T. distichum sediment and from 100% (0–10 cm) to 66.7% (40–50 cm) in A. trabeculosa sediment. The abundances of the archaeal amoA gene in woody plant sediments, ranging from 3.27 × 10⁷ to 2.45 × 10⁸ copies g⁻¹ dry soil, were significantly higher than those in bare mudflat, ranging from 9.23 × 10⁶ to 1.35 × 10⁷ copies g⁻¹ dry soil. The archaeal community, which was significantly affected by pH, microbial carbon and SO₄²⁻ contents according to a canonical correspondence analysis, was significantly altered by plants and soil depth (p < 0.05). These results indicated that the introduction of woody plants stimulates the proliferation of Thaumarchaeota, especially ammonia‐oxidizing archaea, which could be important contributors to the N cycle in forested wetland ecosystems. Copyright © 2017 John Wiley & Sons, Ltd.