Data from: Regional drivers of clutch loss reveal important trade-offs for beach-nesting birds

Coastal birds are critical ecosystem constituents on sandy shores, yet are threatened by depressed reproductive success resulting from direct and indirect anthropogenic and natural pressures. Few studies examine clutch fate across the wide range of environments experienced by birds; instead, most focus at the small site scale. We examine survival of model shorebird clutches as an index of true clutch survival at a regional scale (∼200 km), encompassing a variety of geomorphologies, predator communities, and human use regimes in southeast Queensland, Australia. Of the 132 model nests deployed and monitored with cameras, 45 (34%) survived the experimental exposure period. Thirty-five (27%) were lost to flooding, 32 (24%) were depredated, nine (7%) buried by sand, seven (5%) destroyed by people, three (2%) failed by unknown causes, and one (1%) was destroyed by a dog. Clutch fate differed substantially among regions, particularly with respect to losses from flooding and predation. ‘Topographic’ exposure was the main driver of mortality of nests placed close to the drift line near the base of dunes, which were lost to waves (particularly during storms) and to a lesser extent depredation. Predators determined the fate of clutches not lost to waves, with the depredation probability largely influenced by region. Depredation probability declined as nests were backed by higher dunes and were placed closer to vegetation. This study emphasizes the scale at which clutch fate and survival varies within a regional context, the prominence of corvids as egg predators, the significant role of flooding as a source of nest loss, and the multiple trade-offs faced by beach-nesting birds and those that manage them.

海滨鸟类是沙质海岸生态系统的关键组成部分，却面临直接与间接人为及自然压力导致的繁殖成功率下降的威胁。鲜有研究覆盖鸟类所处的多样环境来探讨窝卵命运（clutch fate），多数研究仅聚焦于小型样地尺度。本研究以模拟滨鸟（shorebird）窝卵的存活率作为真实窝卵存活率的替代指标，在澳大利亚昆士兰州东南部约200公里的区域尺度上开展实验，涵盖了多样的地貌类型、捕食者类群与人类利用模式。本次研究共布设并通过摄像头监测了132个模拟巢，其中45个（34%）在实验暴露期内成功存活。具体损失情况为：35个（27%）因洪涝损毁，32个（24%）被捕食，9个（7%）被沙掩埋，7个（5%）遭人为破坏，3个（2%）因不明原因失效，另有1个（1%）被犬只损毁。不同区域的窝卵命运存在显著差异，尤其体现在洪涝与捕食导致的损失上。‘地形暴露度’是放置于沙丘基部附近漂积带区域的巢死亡的主要驱动因素，这类巢多因海浪（尤其是风暴期间）损毁，仅小部分被捕食。未受海浪损毁的窝卵，其命运主要由捕食者决定，而被捕食概率在很大程度上受区域因素影响。模拟巢背靠的沙丘越高、距植被越近，其被捕食的概率越低。本研究强调了区域尺度内窝卵命运与存活率的变化差异，点明了鸦科鸟类（corvids）作为卵捕食者的重要性、洪涝作为巢损失主要诱因的关键作用，以及滩涂筑巢鸟类及其管理者所面临的多重权衡（trade-offs）关系。