Diversity Pattern of Macrobenthos Associated with Different Stages of Wetland Restoration in the Yellow River Delta

Because wetland restoration projects are becoming more common and are expensive, it is important to evaluate their success. Evaluation studies common use measurements of soils, vegetation, hydrology and wildlife to evaluate the success of wetland restoration. In contrast, the diversity of macrobenthos and their relationships with environmental factors are often neglected. To better understand the success of wetland restoration, we examined the abundance and diversity of macrobenthos in different stages of a freshwater wetland restoration project in the Yellow River Delta in China, with reference to environmental factors that might explain macrobenthic patterns. Macrobenthic species richness and density were greater in the oldest restoration area versus the younger and no-treatment areas. Macrobenthic biomass, however, was greatest in the no-treatment area. The oldest restoration area had deeper water levels, lower salinities, softer and wetter soils, and higher soil organic, nitrogen and carbon contents, and these variables largely distinguished the macrobenthic samples in a CCA analysis. A combination of landscape position and recovery time (time since the restoration was implemented) likely explains the abiotic differences among restoration areas. We recommend an adaptive management strategy, guided by long-term monitoring and experiments, to improve the success of this and other wetland restoration projects.