Changes in Avian Community Composition at a Restored Floodplain Grassland in the Mekong Delta

Abstract. Reinstating flood pulse dynamics has been identified as a method for restoring biotic communities in altered riverine ecosystems. To explore the impacts of flood pulse management on wet grassland bird communities, we surveyed community composition at a restored floodplain grassland in the Plain of Reeds region of the Mekong Delta. Survey sites were situated at different elevations, allowing us to sample the range of grassland habitats found in the study area. Our surveys coincided with three periods of decade-long water management; two surveys occurred during flood pulse water management, and another followed a decade of year-round high-water management. We used PERMANOVA and NMDS to compare avian community composition between these surveys and used foraging guilds to qualitatively assess the impact of water management separate from turnover in individual species. Community composition differed between all surveys at the lowest elevation site, with detection rates for species associated with ponded water, not grassland ecosystems, highest following high-water management. Some grassland species were absent following high-water management and may have been extirpated from survey sites. In the face of grassland loss across the Mekong Delta, our surveys highlight the value of continued flood pulse management for supporting the conservation of wet grassland birds.