Latitudinal gradient of taxonomic richness: combined outcome of temperature and geographic mid-domains effects?
Latitudinal gradient of taxonomic richness: combined outcome of temperature and geographic mid-domains effects?
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DOI：
10.1111/j.1439-0469.2005.00311.x
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发表时间：
2005-08-01
影响因子：
1.9
通讯作者：
Bucher, H
中科院分区：
文献类型：
--
作者：
Brayard, A;Escarguel, G;Bucher, H
几十年来，大规模的大陆和海洋分类丰富度（LGTR）的横向物种的起源和生态后果一直备受争议。在各种假说中，有人提出LGTR是地理中域效应的副产品，即在陆地/海洋界面等物理硬边界之间随机分布类群范围的结果。为了更真实地评估海洋浮游生物的LGTR的起源和进化的作用的中间域的影响，我们提出了一个二维模型的基础上的细胞自动机的方法，在该方法中，海表面温度（SST）和电流被迫在一个随机生成的分支（一个二维的“geophyletic”模型）的地理分布。敏感性实验可以评估电流的影响，SST和地理起源的一个分支上的LGTR的形成和形状的亚热带生物时，再加上一个地理中域的效果。结果进行了讨论，在现有的浮游有孔虫在大西洋的经验LGTR。独立于任何其他生物或非生物参数，包括表面电流和起源/灭绝的绝对和相对速率，我们的模拟表明，耦合的中间域效应与两个关键参数，即形状和强度的SST梯度和地理起源的一个分支，产生现实的多样性模式时，观察到的LGTR现存的大西洋南极有孔虫。结果表明，一个单峰纬向SST梯度和由此产生的双峰LGTR的特点是在赤道附近的物种丰富度下降之间的非线性关系。这种关系表明SST梯度对LGTR产生了中域效应。LGTR的模态值的纬度位置也被发现的模拟分支的地理起源的影响。
For several decades, the origin and ecological consequences of large-scale continental and marine Latitudinal Gradients of Taxonomic Richness (LGTR) have been intensively debated. Among the various hypotheses, it has been proposed that a LGTR is the by-product of a geographic mid-domain effect, i.e. the result of a random distribution of ranges of taxa between physical hard boundaries such as the continent/ocean interface. In order to more realistically evaluate the role of the mid-domain effect on the origin and evolution of the LGTR of marine planktonic organisms, we present a 2D model based on a cellular-automaton approach in which sea surface temperatures (SST) and currents are forced in the biogeographic dispersal of a randomly generated clade (a 2D 'geophyletic' model). Sensitivity experiments allow to evaluate the effects of currents, SST and the geographical origin of a clade on the formation and shape of a LGTR for planktonic organisms when coupled with a geographic mid-domain effect. Results are discussed in the light of the empirical LGTR of extant planktonic Foraminifera in the Atlantic Ocean. Independently of any other biotic or abiotic parameter, inclusive of the surface currents and origination/extinction absolute and relative rates, our simulations show that the coupling of the mid-domain effect with two critical parameters, namely the shape and intensity of the SST gradient and the geographic origin of a clade, produces realistic patterns of diversity when compared with the observed LGTR of extant atlantic planktonic foraminifera. The results illustrate a non-linear relation between a unimodal latitudinal SST gradient and a resulting bimodal LGTR characterized by a drop in species richness near the equator. This relation indicates that the SST gradient exerts a mid-domain effect on the LGTR. The latitudinal positions of the modal values of the LGTR are also found to be influenced by the geographic origin of the simulated clade.