Qian Hong, White Peter S, Song Jong-Suk
Research and Collections Center, Illinois State Museum, 1011 East Ash Street, Springfield, Illinois 62703, USA.
Ecology. 2007 Jun;88(6):1440-53. doi: 10.1890/06-0916.
Conclusions from past studies on the roles that historical and regional factors and contemporary and ecological factors have played in regulating large-scale patterns of species richness have been controversial. Conflicting past results were likely affected by differences in the range of environments analyzed and the scales of observation. Eastern North America and eastern Asia are ideal regions for examining the relative effects of historical and regional factors and contemporary and ecological factors on large-scale patterns of plant species richness because these two regions are closely matched in terms of climate and because their floras originated from the same paleoflora but have experienced different histories of development since the late Paleogene when climate cooling caused their separation. We report on a comprehensive data set of 471 floras ranging from 10 km2 to 4.7 x 10(6) km2 and spanning a wide range of climate and latitude (from 21 degrees to 55 degrees N) to examine whether the contribution of region relative to climate persists from small to large floras and increases from cooler to warmer climates. We found that eastern Asia is richer than eastern North America when sample area, maximum elevation, and climate are accounted for, that this difference diminishes toward higher latitudes, and that elevation plays a much stronger role in eastern Asia than in eastern North America. Our analysis reconciles contemporary/ecological and historical/regional explanations for species richness variation and helps explain why different conclusions have been reached by different authors working in the same geographical areas: the strength of the region effect itself varies with location and range of climatic conditions of the observations.
过去关于历史和区域因素以及当代和生态因素在调节物种丰富度大规模格局中所起作用的研究结论一直存在争议。过去相互矛盾的结果可能受到所分析环境范围和观测尺度差异的影响。北美东部和东亚是检验历史和区域因素以及当代和生态因素对植物物种丰富度大规模格局相对影响的理想区域，因为这两个地区在气候方面密切匹配，而且它们的植物区系起源于同一古植物区系，但自晚古近纪气候变冷导致它们分离以来经历了不同的发展历史。我们报告了一个包含471个植物区系的综合数据集，面积从10平方公里到4.7×10⁶平方公里不等，跨越广泛的气候和纬度范围（北纬21度至55度），以检验相对于气候而言，区域因素的作用是否从小植物区系到大型植物区系持续存在，以及是否从较冷气候到较暖气候逐渐增强。我们发现，在考虑样本面积、最高海拔和气候因素后，东亚比北美东部物种更丰富，这种差异在高纬度地区逐渐减小，而且海拔在东亚比在北美东部发挥的作用要强得多。我们的分析调和了关于物种丰富度变化的当代/生态和历史/区域解释，并有助于解释为什么在同一地理区域工作的不同作者会得出不同的结论：区域效应本身的强度随观测地点和气候条件范围而变化。
