台灣彰化曬池魚塭對供遷徙性水鳥的覓食重要性

Abstract

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Migratory shorebirds rely on inter- and supra-tidal habitats across their migration routes. In the East Asian-Australasia Flyway (EAAF), natural inter- and supratidal zones are being converted for human uses at alarming rates. Nearly 60% of the intertidal zones in Taiwan have been lost in the past 60 years; devastating populations in many shorebird species. Part of the converted landscape is salt pans and aquaculture ponds which can function as artificial wetlands. Migratory shorebirds use these artificial wetlands for feeding and roosting. We calculated the daytime feeding time budgets of shorebirds and the importance of drained (semi-dry) aquaculture ponds in pre-breeding (March, April), post-breeding (August, September, and November) and winter (December) months in Changhua, Taiwan. We found that drained aquaculture ponds provide significant food resources to shorebirds. The Tactile Continuous, Tactile Continuous Deep Water, Pause-Travel guilds, and Black-winged Stilt spent up to 40% of their daytime time budget feeding in the semi-dry ponds pre-breeding. In the post-breeding months, the Tactile Continuous, Tactile Continuous Deep-Water, Visual Continuous Deep-Water guilds, and Pied Avocet spent up to 40% of their time budget feeding in the semi-dry ponds. The Tactile Continuous guild and Black-winged Stilt also spent up to 40% of their time budget feeding in the ponds during winter. The Tactile Continuous (representative species: Red-necked Stint and Dunlin) and Tactile Continuous Deep-Water (representative species: Marsh Sandpiper) guilds and preferentially used aquaculture ponds over intertidal in August and November, respectively. April was the month in which semi-dry ponds provided important food resources to the greatest number of guilds, followed by August, and December. The semi-dry ponds and their surroundings regularly host significant populations of shorebirds numbering from thousands to tens of thousands, highlighting the urgency to conserve these artificial wetlands on a migration route in peril.