Reese Aspen T, Lulow Kyrstin, David Lawrence A, Wright Justin P
Department of Biology Duke University Durham NC USA.
Department of Molecular Genetics and Microbiology Duke University Durham NC USA.
Ecol Evol. 2017 Dec 20;8(2):1196-1205. doi: 10.1002/ece3.3734. eCollection 2018 Jan.
Soils harbor large, diverse microbial communities critical for local and global ecosystem functioning that are controlled by multiple and poorly understood processes. In particular, while there is observational evidence of relationships between both biotic and abiotic conditions and microbial composition and diversity, there have been few experimental tests to determine the relative importance of these two sets of factors at local scales. Here, we report the results of a fully factorial experiment manipulating soil conditions and plant cover on old-field mesocosms across a latitudinal gradient. The largest contributor to beta diversity was site-to-site variation, but, having corrected for that, we observed significant effects of both plant and soil treatments on microbial composition. Separate phyla were associated with each treatment type, and no interactions between soil and plant treatment were observed. Individual soil characteristics and biotic parameters were also associated with overall beta-diversity patterns and phyla abundance. In contrast, soil microbial diversity was only associated with site and not experimental treatment. Overall, plant community treatment explained more variation than soil treatment, a result not previously appreciated because it is difficult to dissociate plant community composition and soil conditions in observational studies across gradients. This work highlights the need for more nuanced, multifactorial experiments in microbial ecology and in particular indicates a greater focus on relationships between plant composition and microbial composition during community assembly.
土壤中存在着庞大且多样的微生物群落，这些群落对于局部和全球生态系统的功能至关重要，而它们受到多种复杂且尚不清楚的过程的控制。特别是，虽然有观察证据表明生物和非生物条件与微生物组成及多样性之间存在关联，但在局部尺度上，很少有实验来确定这两组因素的相对重要性。在此，我们报告了一项全因子实验的结果，该实验在一个纬度梯度上对旧耕地中型生态系统的土壤条件和植物覆盖进行了操控。对β多样性贡献最大的是位点间的变异，但是，在对此进行校正后，我们观察到植物和土壤处理对微生物组成均有显著影响。不同的门与每种处理类型相关联，并且未观察到土壤和植物处理之间的相互作用。各个土壤特征和生物参数也与总体β多样性模式及门的丰度相关。相比之下，土壤微生物多样性仅与位点相关，而与实验处理无关。总体而言，植物群落处理比土壤处理解释了更多的变异，这一结果此前未被认识到，因为在跨越梯度的观察研究中很难区分植物群落组成和土壤条件。这项工作凸显了在微生物生态学中需要进行更细致入微的多因子实验，尤其表明在群落组装过程中应更加关注植物组成与微生物组成之间的关系。
