Biogeography of body size in Pacific island birds
Biogeography of body size in Pacific island birds
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DOI：
10.1111/j.1600-0587.2010.06315.x
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发表时间：
2010-04-01
期刊：
影响因子：
5.9
通讯作者：
Jetz, Walter
中科院分区：
文献类型：
--
作者：
Boyer, Alison G.;Jetz, Walter
与大陆上的脊椎动物相比，许多岛屿上的脊椎动物在体型上经历了迅速而剧烈的变化。本文探讨了两种众所周知的岛屿体型变化规律——大体型物种在岛屿上变矮和小体型物种在岛屿上变大的趋势，即“岛屿规律”，以及岛屿群落最大和最小体型随岛屿面积的变化规律。利用化石和现代数据，我们研究了太平洋岛屿鸟类的体型和岛屿面积之间的关系，包括在进化枝和岛屿组合水平上。结果表明，各岛屿最小鸟的体型随岛屿面积的增加而减小，最大鸟的体型随岛屿面积的增加而增大。同样，在进化枝内，小体群的体型变小，而大体群的体型从小岛到大岛增加，与岛屿规律一致。然而，枝内的大小变化幅度不足以解释最大尺寸随岛屿面积的整体尺度变化。相反，这种模式主要是由大型岛屿上不会飞的鸟类的进化所驱动的。在过去的几千年里，人类在岛屿上造成的灭绝严重影响了大型、不会飞的鸟类，其结果是这种宏观生态模式实际上已经被抹去了。在控制了生物地理区域和岛屿面积的影响后，我们发现岛屿生产力是无飞鸟类最大体型的最佳预测因子。这一结果，以及不会飞的鸟类和岛屿哺乳动物在最大体型上的惊人相似性，表明在岛屿规则和岛屿体型极端尺度中，存在一种共同的能量机制，将体型和陆地面积联系起来。
Many insular vertebrates have undergone rapid and dramatic changes in body size compared to their mainland counterparts. Here we explore the relationship between two well known patterns of island body size - the tendency for large-bodied species to dwarf and small-bodied species to get larger on islands, known as the "island rule", and the scaling of maximum and minimum body size of island assemblages with island area. Drawing on both fossil and modern data, we examined the relationship between body size and island area in Pacific island birds, both within clades and at the island assemblage level. We found that the size of the smallest bird on each island decreased with island area while the maximum body size increased with island area. Similarly, within clades the body size of small-bodied groups decreased and large-bodied groups increased from small to large islands, consistent with the island rule. However, the magnitude of size change within clades was not sufficient to explain the overall scaling of maximum size with island area. Instead, the pattern was driven primarily by the evolution of very large, flightless birds on large islands. Human-mediated extinctions on islands over the past few millennia severely impacted large, flightless birds, to the effect that this macroecological pattern has been virtually erased. After controlling for effects of biogeographic region and island area, we found island productivity to be the best predictor of maximum size in flightless birds. This result, and the striking similarities in maximum body size between flightless birds and island mammals, suggests a common energetic mechanism linking body size and landmass area in both the island rule and the scaling of island body size extremes.