João Paulino

and 3 more

Natural wetlands are globally threatened, while artificial wetlands such as rice fields are expanding. Rice fields are important habitats for waterbirds, although their ecological role and relevance for conservation remains uncertain. This study employs community and functional ecology analyses to understand how the structure and functions of waterbird communities in rice fields compare to those in other habitats within an agricultural landscape encompassing five habitats: saltpans, lakes, intertidal areas, pastures, and rice fields. Over two years, waterbird counts were conducted every 15 days in these habitats. Non-metric multidimensional scaling (NMDS) was used to compare the composition and functional structure of the waterbird communities. Significant differences in composition and functional structure of the communities among habitats were found throughout the year likely driven by two gradients: a spatial gradient, determined by the presence of permanent water cover, and a temporal gradient, reflecting seasonality throughout the year. Rice fields occupy a central position within these gradients, exhibiting characteristics of both aquatic and terrestrial environments. The composition and functional structure of waterbird communities in rice fields undergoes significant changes throughout the year, presumably in response to environmental fluctuations associated with the annual rice production cycle, with large carnivorous birds prevalent during the rice growing season and herbivorous birds becoming dominant after harvest. In contrast, the other habitats maintain more consistent year-round communities, reflecting their stable environmental conditions. Waterbird communities in rice fields offer significant services in nutrient cycling and pest control, while lakes are more effective in providing services related to herbivory, and intertidal areas as environmental quality sentinels. This study suggests that rice fields play a complementary role to other habitats in the studied landscape, likely acting as a buffer and potentially mitigating the loss of waterbird populations amid the global decline of natural wetlands.