Patterns of waterbird community composition across a natural and restored wetland landscape mosaic, Yellow River Delta, China

Habitat restoration can help mitigate the extensive loss and degradation of estuarine and coastal wetlands that have consequently eroded the integrity of many migratory flyways and wintering habitat for waterbird populations. Assessing the impact of restoration strategies however relies on empirical data on waterbird community distribution patterns across natural and restored wetland components. We conducted habitat and waterbird surveys across six natural and restored wetland regions in the Yellow River Delta Nature Reserve (YRDNR), eastern China, between 2007 and 2009. We recorded 93 waterbird species, including populations of 21 global conservation importance species. Community composition was stratified into distinctive clusters with compositional structure changing across these natural, modified and restored wetland components. NMDS ordination revealed that waterbird communities in restored wetlands were significantly different from those in natural and modified wetland components. Community distribution patterns were strongly influenced by environmental gradients (most noticeably salinity), water-level regulation, vegetation composition and differences in protected status. We found marked temporal patterns in waterbird community composition, which may be predictable for the different wetland components across the YRDNR landscape. Our study highlights the conservation benefits of restoring smaller wetland components in improving the ecological integrity of the wider wetland landscape mosaic for waterbird populations. A more coherent and intensive landscape management of water-level regulation and restoration of salinity gradients will be fundamental for wetland and waterbird conservation throughout the YRDNR.

Research highlights
► The coastal and estuarine wetlands of the Yellow River Delta are important stopover site and wintering area for 93 waterbird species, including populations of 21 global conservation importance species.
► Waterbird community composition changes across the natural and restored wetland landscape mosaic.
► The waterbird community composition of restored wetlands was significant different from those in natural and modified wetlands, and also differed between the restored wetland components.
► Water-level and salinity regulation in the restored wetlands is of critical important for helping to maintain the distinctive waterbird communities of these habitats.
► Our study highlights the conservation benefits of restoring smaller wetland components for improving the ecological integrity of the wider wetland landscape mosaic for waterbird populations.