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图注:克里格法(Kriging)是地质统计学的主要内容之一。从统计意义上说,是从变量相关性和变异性出发,在有限区域内对区域化变量的取值进行无偏、最优估计的一种方法;从插值角度讲是对空间分布的数据求线性最优、无偏内插估计一种方法。 (正文) *Nees Institute for Biodiversity of Plants, University of Bonn, Meckenheimer Allee 170, D-53115 Bonn, Germany; and Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive MC 0116, La Jolla, CA 92093-0116 Edited by F. Stuart Chapin III, University of Alaska, Fairbanks, AK, and approved January 25, 2007 (received for review September 22, 2006) Plants, with an estimated 300,000 species, provide crucial primary production and ecosystem structure. To date, our quantitative understanding of diversity gradients of megadiverse clades such as plants has been hampered by the paucity of distribution data. Here, we investigate the global-scale species-richness pattern of vascular plants and examine its environmental and potential historical determinants. Across 1,032 geographic regions worldwide, potential evapotranspiration, the number of wet days per year, and measurements of topographical and habitat heterogeneity emerge as core predictors of species richness. After accounting for environmental effects, the residual differences across the major floristic kingdoms are minor, with the exception of the uniquely diverse Cape Region, highlighting the important role of historical contingencies. Notably, the South African Cape region contains more than twice as many species as expected by the global environmental model, confirming its uniquely evolved flora. A combined multipredictor model explains 70% of the global variation in species richness and fully accounts for the enigmatic latitudinal gradient in species richness. The models illustrate the geographic interplay of different environmental predictors of species richness. Our findings highlight that different hypotheses about the causes of diversity gradients are not mutually exclusive, but likely act synergistically with water-energy dynamics playing a dominant role. The presented geostatistical approach is likely to prove instrumental for identifying richness patterns of the many other taxa without single-species distribution data that still escape our understanding. 美国圣迭戈市加州大学和德国波恩大学的生物学家们合作绘制出一张世界植物多样性分布图,包含了数十万物种。科学家声称他们的这张图是有史以来最详尽的生物多样性分布图。 (资料来源:哪个出版物中摘录已经记不清了;非盈利性转载;如有版权之争,当告知补上标注或删除) |
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