Water Bird Communities in Nonoperational Cigu Salt Pan Wetland of Varying Land Elevation and Water Depth on the Southwest Taiwan Coast

摘要

The Black-faced Spoonbill ( Platalea minor ) is a critically endangered species. More than 50% of these spoonbills winter regularly on the southwestern coast of Taiwan. From 2007 to 2019, the rate of increase of the Black-faced Spoonbill population was only 10.5%, which is lower than the rate of 12.0% per year reported between 1991 and 2004. Black-faced Spoonbills have experienced several bottlenecks, and problems may exist in their breeding and/or in wintering habitats. Understanding the ecological environment of their habitats in Taiwan is an important issue, including the current use of water birds, the water depth of their habitats and even the aquatic plants. A total population of 93,614 birds of 88 species was recorded in a survey of the Cigu salt pan from October 2017 to October 2018. The biodiversity H' (loge) of the total birds was 2.67. Dunlin ( Calidris alpina ) was the most dominant species with a population of 21,053 (22.5%), followed by Kentish Plover ( Charadrius alexandrinus ) with a population of 20,350 (21.7%). The largest area of terrain elevation at - 1.0 to - 0.2 m was 685.4 ha (38.5%) and at - 0.2 to - 0.1 m was 320.4 ha (18.0%). Between 2017 and 2018, the similarity in water depth classification was 47.2%, reflecting climate change, a degree of water accumulation, and the wader utilization situation. A strategy for maintaining biodiversity in the Cigu salt pan wetland and conserving spoonbills is therefore proposed in this paper.