Mitigation of urbanisation effects on aquatic ecosystems by synchronous ecological restoration

Ecosystem degradation and biodiversity loss have been caused by economic booms in developing countries over recent decades. In response, ecosystem restoration projects have been advanced in some countries but the effectiveness of different approaches and indicators at large spatio-temporal scales (i.e., whole catchments) remains poorly understood. Our datasets with a diverse array of 440 aquatic restoration projects including wastewater treatment, constructed wetlands, plant/algae salvage, and dredging of contaminated sediments implemented and maintained from 2007 to 2017 across more than 2000km2 of the northwest Taihu basin (Yixing, China). Synchronized investigations of water quality and invertebrate communities were conducted before and after restoration. Our datasets showed that even though there was rapid urbanization at this time, nutrient concentrations (NH4+-N, TN, TP) and biological indices of benthic invertebrates (taxonomic richness, Shannon diversity, sensitive taxon density) improved significantly across most of the study area. Improvements were associated with the type of restoration project, with projects targeting pollution sources leading to the clearest ecosystem responses compared with those remediating pollution sinks. However, in some locations, the recovery of biotic communities appears to lag behind nutrients (e.g. nitrogen and phosphorus), likely reflecting long-distance re-colonization routes for invertebrates given the level of pre-restoration degradation of the catchment.

Methods
We collected the data of restoration projects from the Development and Reform Commission of Jiangsu province. And monitored the recovery of 63 locations by sampling each site both before (2007) and after (2017) the implementation of the restoration works, indices include benthic macroinvertebrates and water nutrients.