Ge Yuan, He Ji-zheng, Zhu Yong-guan, Zhang Jia-bao, Xu Zhihong, Zhang Li-mei, Zheng Yuan-ming
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
ISME J. 2008 Mar;2(3):254-64. doi: 10.1038/ismej.2008.2. Epub 2008 Jan 31.
Contemporary environmental disturbances and historical contingencies are considered to be major factors driving current differences in microbial diversity. However, little was known about their relative importance. This study combines culture-independent molecular techniques and advanced statistical analyses to examine quantitatively the relative importance of contemporary disturbances and historical contingencies in influencing large-scale soil bacterial diversity using a large set of manipulated field-based molecular data (212 samples). Contemporary disturbances were represented by applications of different fertilizers N, P, K and organic manure (OM) and historical contingencies by distinct geographic sampling locations and soil profiles. Multivariate regression tree (MRT) analysis showed that diversity estimates were mainly distinguished by sampling locations, which explained 40.8% of the variation in bacterial diversity, followed by soil profiles (19.5%), sampling time (13.1%), OM (3.7%) and P (1.8%). Aggregated boosted tree (ABT) analysis showed that the relative importance of different categorical factors on soil bacterial diversity variation was ranked as sampling locations, soil profiles, sampling time, OM and P. Both MRT and ABT analyses showed that historical contingencies were the dominant factor driving variation in bacterial diversity across a regional scale (about 1000 km), whereas some contemporary disturbances also caused variation in bacterial diversity at a local scale. This study demonstrated that past events and contemporary disturbances had similar influence on soil bacterial diversity to that documented for macroorganisms, indicating that there might be some common aspects of biogeography to all organisms.
当代环境干扰和历史偶然性被认为是导致当前微生物多样性差异的主要因素。然而，人们对它们的相对重要性知之甚少。本研究结合了非培养分子技术和先进的统计分析方法，利用大量基于田间操作的分子数据（212个样本），定量研究当代干扰和历史偶然性在影响大规模土壤细菌多样性方面的相对重要性。当代干扰通过施用不同的肥料氮、磷、钾和有机肥（OM）来体现，历史偶然性则通过不同的地理采样地点和土壤剖面来体现。多元回归树（MRT）分析表明，多样性估计主要由采样地点区分，采样地点解释了细菌多样性变异的40.8%，其次是土壤剖面（19.5%）、采样时间（13.1%）、OM（3.7%）和磷（1.8%）。聚合增强树（ABT）分析表明，不同分类因素对土壤细菌多样性变异的相对重要性排序为采样地点、土壤剖面、采样时间、OM和磷。MRT和ABT分析均表明，历史偶然性是驱动区域尺度（约1000公里）细菌多样性变异的主导因素，而一些当代干扰也在局部尺度上导致了细菌多样性的变异。本研究表明，过去事件和当代干扰对土壤细菌多样性的影响与大型生物的情况相似，这表明所有生物的生物地理学可能存在一些共同之处。
