Experiment using semi-natural meadow vegetation for restoration of river revetments: A case study in the upper reaches of the Yangtze River

Abstract

Mixed-species vegetation, such as that in semi-natural meadows, is increasingly adopted in urban green infrastructure to enhance habitat quality and aesthetic value; however, little is known regarding the consequences of using meadow mixes in river revetments. In the present study, 20 herbaceous species that naturally occur in habitats with infrequent and periodic inundation were mix-planted in hydrology-induced and disturbed revetments along the mainstream of the Yangtze River in the typical mountain city of Chongqing, China. The experimental meadow communities exhibited persistence under the constraints imposed by the prevailing hydrological conditions and disturbances, such as the extremely high soil wetness variability between periodical inundation on seedlings, the drought during the summer, and the transition between runoff washout and quick drainage. All planted species survived under the changing hydrological conditions, while the semi-natural meadow maintained good growth and visual landscape quality. Meadow mixes were significantly superior in species richness, abundance and structural diversity over the existing homogeneous community dominated by invasive liana Humulus scandens. Community data suggest that species richness has increased by more than 60% in the meadow mix over the existing vegetation. The meadow communities resisted invasion by indigenous weeds and colonising species that spread through wind-dispersal and hydrochorous transport from the upstream catchment. We therefore recommend prioritising taxonomically diverse meadows for river revetments wherever possible. This study provides a valid framework that can be used to inform future vegetation restoration schemes in river revetments affected by complex hydrological variation and disturbances. The methodology is applicable to a broad range of vegetative revetment structures.