Relationship between nitrogen removal and habitat provisioning functions of small wetlands originated from abandoned paddy fields: multisite comparison and experimental verification

• Published in: Landscape and ecological engineering Vol. 21; no. 1; pp. 163 - 174
• Main Authors: Kato, Hiroki, Kohzu, Ayato, Nishihiro, Jun
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.01.2025; Springer Nature B.V
• Subjects: Biodiversity; biodiversity conservation; Biomedical and Life Sciences; canopy; Civil Engineering; Drainage channels; Ecological function; Endangered species; Environmental Management; Generalized linear models; habitats; Ion concentration; Japan; lakes; Landscape Ecology; Landscape/Regional and Urban Planning; landscapes; Life Sciences; Nature Conservation; nitrates; nitrogen; Nitrogen removal; Original Paper; paddies; Plant Ecology; Population decline; principal component analysis; Principal components analysis; Provisioning; Quality management; rice; Rice fields; species; Spring water; Statistical models; Surface water; surface water level; Water conservation; Water depth; Water discharge; Water quality; Water quality management; watersheds; Wetlands; Biodiversity; Plant conservation; Old field; Water quality; Eutrophication
• ISSN: 1860-1871; 1860-188X
• DOI: 10.1007/s11355-024-00631-8

Although wetlands serve various ecological functions, the relationships among the functions remain unclear. From an ecological perspective, abandoned rice paddies may function as wetlands. We analyzed the relationship between the ecological functions of nitrogen removal from surface water and habitat provisioning to wetland plants in 32 wetlands that originated from abandoned rice paddies in the catchment of Lake Inbanuma, Japan. Results of a principal component analysis suggested that these functions can be synergistic in wetlands with a greater rate of spring water discharge, water depth, and canopy openness. The importance of water depth for both functions was also revealed by generalized linear models. We conducted an experimental restoration in a dry abandoned rice paddy in which the surface water depth was increased by damming an artificial drainage channel. After the restoration, the nitrate ion concentration at the outlet of the site had declined by half. Furthermore, seven endangered wetland species were re-established from the propagule banks. Our results suggest that through improvement of the hydrological condition of abandoned paddy fields, they can become wetlands that contribute to water quality management and biodiversity conservation.