Spatial turnover in the global avifauna
Spatial turnover in the global avifauna
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DOI：
10.1098/rspb.2007.0236
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发表时间：
2007-07-07
影响因子：
4.7
通讯作者：
Blackburn, Tim M.
中科院分区：
文献类型：
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作者：
Gaston, Kevin J.;Davies, Richard G.;Blackburn, Tim M.
尽管全球物种发生空间周转模式对许多生态问题具有广泛影响，但与全球物种丰富度模式不同，人们对全球物种发生空间周转模式的研究很少。在这里，使用一个数据库的鸟类繁殖分布，我们提出了第一个全球地图的空间营业额的变化，为整个分类类，一个模式，迄今为止仍然在很大程度上是一个问题的猜测，基于理论的预期和外推不一致的模式，从不同的地理领域。我们用这些地图来测试四个预测生态位理论的形式，这种变化应该采取，即营业额应增加物种丰富度，向低纬度，并与陡峭的环境梯度和营业额的变化主要是由稀有（限制）物种。与预测相反，我们表明，营业额是高的，在极低和极高的物种丰富度的地区，并没有增加强烈的热带地区，并与平均环境条件和空间变化在这些条件。这些结果是密切相关的进一步重要和新颖的发现，即全球格局的空间营业额主要是由广泛分布的物种，而不是限制。这补充了最近的证据，即物种丰富度的空间格局也主要是由分布广泛的物种驱动的，从而为建立一个统一的模型，说明地球主要陆地块内部和之间的陆地生物多样性如何变化做出了重要贡献。
Despite its wide implications for many ecological issues, the global pattern of spatial turnover in the occurrence of species has been little studied, unlike the global pattern of species richness. Here, using a database on the breeding distributions of birds, we present the first global maps of variation in spatial turnover for an entire taxonomic class, a pattern that has to date remained largely a matter of conjecture, based on theoretical expectations and extrapolation of inconsistent patterns from different biogeographic realms. We use these maps to test four predictions from niche theory as to the form that this variation should take, namely that turnover should increase with species richness, towards lower latitudes, and with the steepness of environmental gradients and that variation in turnover is determined principally by rare (restricted) species. Contrary to prediction, we show that turnover is high both in areas of extremely low and high species richness, does not increase strongly towards the tropics, and is related both to average environmental conditions and spatial variation in those conditions. These results are closely associated with a further important and novel finding, namely that global patterns of spatial turnover are driven principally by widespread species rather than the restricted ones. This complements recent demonstrations that spatial patterns of species richness are also driven principally by widespread species, and thus provides an important contribution towards a unified model of how terrestrial biodiversity varies both within and between the Earth's major land masses.