ため池・水田地帯におけるサギ類の生息場所分離

概要

論文の詳細を見る
Traditional rice paddy cultivation in Japan has continued to supply wading birds with good foraging habitats. We studied habitat segregation among species of herons and egrets throughout one year in a pond-paddy complex area in Harima, Hyogo Prefecture. The principal foraging habitats diffed between diurnal egrets: arable and grassland for cattle egrets Bubulcus ibis, emergent vegetation at the pond-shore for intermediate egrets Egretta intermedia, pond open water for great egrets Egretta alba, and highly diverse habitats for little egrets Egretta garzetta. Smaller percentages of grey herons Ardea cinerea and night herons Nycticorax nycticorax were recorded as foraging during the daytime, reflecting their dusk/nocturnal activity patterns. The foraging habitats of each diurnal species were essentially the same throughout the study period, with partial seasonal changes some of which occurrcd commonly among species. The diversity of foraging habitats of little egrets was a result of their seasonal movement between habitats, which was probably related to agricultural water-level control. The seasonal change of foraging habitats by little egrets caused serious habitat overlaps with other species, some of which were recognized to be superficial. The overlap between little egrets and great egrets on pond open water in autumn, however, was considered to be a true overlap due to temporarily rich food availability.
日本生態学会の論文
1998-04-25