Wind, Waves, and Wing Loading: Morphological Specialization May Limit Range Expansion of Endangered Albatrosses
Wind, Waves, and Wing Loading: Morphological Specialization May Limit Range Expansion of Endangered Albatrosses
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DOI：
10.1371/journal.pone.0004016
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发表时间：
2008-12-24
期刊：
影响因子：
3.7
通讯作者：
Nakamura, Noboru
中科院分区：
文献类型：
--
作者：
Suryan, Robert M.;Anderson, David J.;Nakamura, Noboru
在鸟类飞行的各种适应中，使大型信天翁能够利用风能和波浪能量进行有效的长途飞行的形态特征是无与伦比的。因此，大多数信天翁的生物地理分布仅限于地球上风力最大的海洋地区；然而，也有例外。北太平洋和中太平洋的物种繁殖(Phoebasria spp.)生活在风速和波高比南半球属低的地区，在体型和空气动力学性能上有很大的属内差异。在这里，我们测试了这样的假设，即区域风浪制度解释了观察到的信天翁形态差异，并将它们的空气动力学性能与这个全球分布的鸟类家族中其他三个属的代表进行了比较。在北太平洋和中太平洋，两个物种(短尾信天翁和波纹信天翁)体型明显较大，但在高生产力的沿海上升流系统附近的繁殖范围最小。然而，与波浪型信天翁相比，短尾信天翁的翅膀负荷(每升力面积的重量)高出60%。事实上，经过计算，唯一的热带信天翁物种--波纹信天翁的空气动力性能与其较小的同系物(黑脚信天翁和永恒信天翁)更相似，后者的翅膀负荷相对较低，觅食范围要大得多，其中包括生产力相对较低的中央大洋环流。在全球范围内，短尾和波浪型信天翁的空气动力学性能最不寻常的是它们的身体大小，但与它们繁殖季节觅食范围内的风向一致。我们的结果首次将全球风浪模式与信天翁的空气动力学相结合，从而确定了形态专门化，这可能解释了两个濒危信天翁物种有限的繁殖范围。这些结果对于了解过去和未来全球信天翁的分布范围，特别是关于气候变化对盆地尺度和区域风场的影响，具有进一步的意义。
Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we compare their aerodynamic performance to representatives from the other three genera of this globally distributed avian family. In the North and Central Pacific, two species (short-tailed P. albatrus and waved P. irrorata) are markedly larger, yet have the smallest breeding ranges near highly productive coastal upwelling systems. Short-tailed albatrosses, however, have 60% higher wing loading (weight per area of lift) compared to waved albatrosses. Indeed, calculated aerodynamic performance of waved albatrosses, the only tropical albatross species, is more similar to those of their smaller congeners (black-footed P. nigripes and Laysan P. immutabilis), which have relatively low wing loading and much larger foraging ranges that include central oceanic gyres of relatively low productivity. Globally, the aerodynamic performance of short-tailed and waved albatrosses are most anomalous for their body sizes, yet consistent with wind regimes within their breeding season foraging ranges. Our results are the first to integrate global wind and wave patterns with albatross aerodynamics, thereby identifying morphological specialization that may explain limited breeding ranges of two endangered albatross species. These results are further relevant to understanding past and potentially predicting future distributional limits of albatrosses globally, particularly with respect to climate change effects on basin-scale and regional wind fields.