Data for: Waterbird abundance in aquaculture ponds: the significance of day and night and pond type

The loss of coastal wetlands represents a grave threat to waterbirds,
prompting the use of artificial wetlands, such as aquaculture ponds, as a
means of conservation. Aquaculture ponds are common in coastal areas and
provide production value and ecological function as waterbird habitats.
However, certain piscivorous birds may cause economic losses to the
aquaculture industry. Different types of ponds provide habitat for various
bird assemblages, and waterbirds exhibit nocturnal feeding behavior and
utilize habitats distinct from those used during the day. Most waterbird
surveys were conducted during the daytime, limiting our understanding of
their nocturnal habitat utilization. This study conducted diurnal and
nocturnal surveys on shorebirds, waterfowl, and Black-crowned Night Heron
(Nycticorax nycticorax) ten times in three aquaculture ponds situated in
the Cigu District of Tainan, namely fish/shrimp, hard clam, and abandoned
ponds between October 2021 and November 2022. The results showed no
significant difference in shorebird density between day and night.
However, shorebird density in fish/shrimp ponds was the highest and
significantly higher than in abandoned ponds. Conversely, waterfowl
density exhibits a significant increase in abandoned ponds compared to the
other two pond types, irrespective of diurnal or nocturnal conditions.
Furthermore, waterfowl density in abandoned ponds is significantly higher
during daylight hours compared to the nocturnal period. In the daytime,
the density of night herons was significantly higher in abandoned ponds
than in the other two ponds. Nevertheless, during nighttime hours,
fish/shrimp ponds exhibit the highest density of Black-crowned Night
Herons, significantly surpassing that found in hard clam ponds. Notably,
water coverage also influences the density of both shorebirds and
waterfowl. The foraging frequency of waterfowl and night herons was
greater during nocturnal hours, while shorebirds did not exhibit
significant variations between day and night. Consequently, this study
underscores the significance of considering both diurnal and nocturnal
habitats in formulating strategies for waterbird conservation.

海岸湿地的丧失对水鸟（waterbirds）构成了严重威胁，这促使人们将水产养殖池塘（aquaculture ponds）等人工湿地作为水鸟保护的手段。水产养殖池塘在沿海区域分布广泛，兼具生产价值与作为水鸟栖息地的生态功能。然而，部分食鱼鸟类可能会给水产养殖业造成经济损失。不同类型的池塘为不同的鸟类群落提供栖息环境，且水鸟会表现出夜间觅食行为，并利用与日间不同的栖息地。目前大多数水鸟调查均在日间开展，这限制了我们对其夜间栖息地利用情况的认知。本研究于2021年10月至2022年11月期间，在台南市七股区的3处水产养殖池塘（分别为鱼虾混养塘、硬壳蛤养殖塘与废弃养殖塘）内，对滨鸟（shorebird）、水禽（waterfowl）以及夜鹭（Black-crowned Night Heron，学名Nycticorax nycticorax）开展了10次昼夜调查。调查结果显示，滨鸟的种群密度在日间与夜间并无显著差异，但鱼虾混养塘内的滨鸟密度最高，且显著高于废弃养殖塘。与之相反，无论日间还是夜间，废弃养殖塘内的水禽密度均显著高于另外两类池塘；此外，废弃养殖塘内的水禽密度在日间显著高于夜间。日间阶段，废弃养殖塘内的夜鹭密度显著高于另外两类池塘，但在夜间时段，鱼虾混养塘内的夜鹭密度最高，显著高于硬壳蛤养殖塘。值得注意的是，水域覆盖度同样会对滨鸟与水禽的种群密度产生影响。水禽与夜鹭的觅食频率在夜间更高，而滨鸟的觅食频率在日间与夜间并无显著差异。综上，本研究强调，在制定水鸟保护策略时，需同时考虑其日间与夜间栖息环境的重要性。