淹水的蔥頭田可作為，岸鳥於秋過境期間的替代覓食棲地

Flooded shallot fields as alternative foraging habitat for shorebird during autumn migration period

在潮間帶灘地不斷減少下，人為濕地對岸鳥保育日益重要。水稻田已知是岸鳥會利用 的人為濕地類型，但對於岸鳥利用旱田的相關研究較為缺乏。蔥頭（分蔥，Allium ascalonicum） 是臺南沿海的重要旱作作物之一，其中以七股為最大產區。農民每年非種植期的 6-9 月會 將蔥頭田蓄水，淹水的農田形成了暫時性濕地，吸引岸鳥前來利用。本研究針對七股淹水 蔥頭田進行底棲大型無脊椎動物相調查，以評估可供岸鳥的潛在食物資源。此外並在水位 降低的蔥頭田進行覆網實驗，以了解岸鳥如何利用這些食物。水生寡毛類為淹水期間蔥頭 田中最優勢的底棲大型無脊椎動物。但在農民為了去除福壽螺而施撒苦茶粕之後，水生寡 毛類密度顯著減少，搖蚊幼蟲成為最優勢的類群。淹水的蔥頭田於 9 月中會陸續排水準備 耕作，水位降低的田裡吸引許多岸鳥覓食。岸鳥以搖蚊幼蟲為主要捕食對象，並顯著減少 其密度，於 3 天的實驗期間平均約減少了 66%。本研究證實淹水蔥頭田於秋過境期間提供 了岸鳥適合的覓食棲地。

"With continuous loss and degradation of intertidal mud flats, artificial wetlands have become increasingly important for the conservation of shorebirds. Rice fields are known to provide habitats for shorebirds, but there is a lack of research on upland crops. Shallot (Allium ascalonicum) is an important upland crop in the coastal areas of Tainan, of which Qigu is the largest producing area. The shallot fields are flooded from June to September during the non-planting season and attract shorebirds. In this study, a benthic macroinvertebrate survey was conducted on flooded shallot fields at Qigu to assess the potential food resources of shorebirds. In addition, an exclosure experiment was conducted to understand how shorebirds exploit these foods. Aquatic oligochaetes were the most abundant benthic macroinvertebrates in flooded period. However, after the farmers used tea seed meal to kill Pomacea canaliculata, the density of aquatic oligochaetes was significantly reduced, and chironomid larva became the most abundant group. The flooded fields were drained after mid-September. Several species of shorebirds were attracted to fields with lower water level. Shorebirds mainly feed on chironomid larvae and significantly reduce their density. During the 3-day exclosure xperiment, the average density of chironomid larvae was reduced by 66%. This study confirms that the flooded shallot fields provide suitable foraging habitats for shorebirds during autumn migration period."