Department of Biology, Indiana University, 1001 East Third Street, Bloomington, Indiana, 47405, USA.
Department of Ecology and Evolutionary Biology and Kansas Biological Survey, The University of Kansas, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045, USA.
Ecol Appl. 2018 Apr;28(3):736-748. doi: 10.1002/eap.1681. Epub 2018 Mar 5.
Given that mycorrhizal fungi play key roles in shaping plant communities, greater attention should be focused on factors that determine the composition of mycorrhizal fungal communities and their sensitivity to anthropogenic disturbance. We investigate changes in arbuscular mycorrhizal (AM) fungal community composition across a precipitation gradient in North American grasslands as well as changes occurring with varying degrees of site disturbance that have resulted in invasive plant establishment. We find strong differentiation of AM fungal communities in undisturbed remnant grasslands across the precipitation gradient, whereas communities in disturbed grasslands were more homogeneous. These changes in community differentiation with disturbance are consistent with more stringent environmental filtering of AM fungal communities in undisturbed sites that may also be promoted by more rigid functional constraints imposed on AM fungi by the native plant communities in these areas. The AM fungal communities in eastern grasslands were particularly sensitive to anthropogenic disturbance, with disturbed sites having low numbers of AM fungal operational taxonomic units (OTUs) commonly found in undisturbed sites, and also the proliferation of AM fungal OTUs in disturbed sites. This proliferation of AM fungi in eastern disturbed sites coincided with increased soil phosphorus availability and is consistent with evidence suggesting the fungi represented by these OTUs would provide reduced benefits to native plants. The differentiation of AM fungal communities along the precipitation gradient in undisturbed grasslands but not in disturbed sites is consistent with AM fungi aiding plant adaptation to climate, and suggests they may be especially important targets for conservation and restoration in order to help maintain or re-establish diverse grassland plant communities.
鉴于菌根真菌在塑造植物群落方面起着关键作用，应更加关注决定菌根真菌群落组成及其对人为干扰敏感性的因素。我们研究了北美草原降水梯度上丛枝菌根（AM）真菌群落组成的变化，以及由于入侵植物的建立而导致的不同程度的干扰所发生的变化。我们发现，在未受干扰的残余草原上，AM 真菌群落沿着降水梯度有强烈的分化，而在受干扰的草原上，群落则更加均匀。这些与干扰有关的群落分化变化与未受干扰地点中 AM 真菌群落更严格的环境过滤一致，这也可能是由这些地区本地植物群落对 AM 真菌施加的更严格的功能约束所促进的。东部草原的 AM 真菌群落对人为干扰特别敏感，受干扰的地点 AM 真菌的操作分类单位（OTU）数量较少，而在受干扰的地点，AM 真菌的 OTU 也大量增殖。这些 OTU 所代表的 AM 真菌在东部受干扰地点的大量增殖与土壤磷的可利用性增加相一致，这与这些 OTU 提供的减少的原生植物益处的证据一致。在未受干扰的草原上，AM 真菌群落沿着降水梯度的分化，但在受干扰的地点则没有，这与 AM 真菌有助于植物适应气候一致，并表明它们可能是保护和恢复的特别重要的目标，以帮助维持或重新建立多样化的草原植物群落。
