Session3: Environmental Hydraulics
Title: EVALUATION OF OCCURRENCE TENDENCY AND HABITAT TYPES FOR WADING BIRDS IN JAPANESE RIVERS USING DATASETS FROM THE NATIONAL CENSUS ON RIVER ENVIRONMENTS
Kota Tawa, Terutaka Mori, Yuichi Kayaba, Keigo Nakamura
We studied the occurrence tendency and habitat types of wading birds in the large river systems of Japan using datasets from the National Census on River Environments. A total of 81 wader species were recorded. A higher number of species of wading birds were found in some regions that have important mudflat habitats in the East Asian-Australasian Flyway, than in other regions. However, not only waders that inhabit estuaries and mudflats but also many waders that inhabit inland freshwater bodies were recorded in most Japanese regions. This result suggests that river environments are important habitats for many wader species. On the other hand, the number of many wader species has recently decreased nationwide. Especially, the populations of waders that use inland wetlands as foraging and breeding sites showed a high decreasing tendency. These results suggested a decline in the number of healthy inland wetlands that contain wader habitats. We suggest that river restoration programs in Japan focus on improving the health of wetland environments by maintaining floodplain water bodies, gravels, and aquatic plant belts.