This study explores the relationships of AM fungal abundance and diversity with biotic (host plant, ungulate grazing) and abiotic (soil properties, precipitation) factors in the Serengeti National Park, Tanzania. Soil and root samples were collected from grazed and ungrazed plots at seven sites across steep soil fertility and precipitation gradients. AM fungal abundance in the soil was estimated from the density of spores and the concentration of a fatty acid biomarker. Diversity of AM fungi in roots and soils was measured using DNA sequencing and spore identification. AM fungal abundance in soil decreased with grazing and precipitation and increased with soil phosphorus. The community composition of AM fungal DNA in roots and soils differed. Root samples had more AM fungal indicator species associated with biotic factors (host plant species and grazing), and soil samples had more indicator species associated with particular sample sites. These findings suggest that regional edaphic conditions shape the site-level species pool from which plant species actively select root-colonizing fungal assemblages modified by grazing. Combining multiple measurements of AM fungal abundance and community composition provides the most informed assessment of the structure of mycorrhizal fungal communities in natural ecosystems.

中文翻译：

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根和土壤中的丛枝菌根真菌对塞伦盖蒂的生物和非生物因子有不同的反应。

这项研究探讨了坦桑尼亚塞伦盖蒂国家公园中AM真菌的丰度和多样性与生物（寄主植物，有蹄类动物放牧）和非生物（土壤特性，降水）因子之间的关系。从七个土壤肥力和降水梯度的放牧和非湿地样地收集土壤和根样品。根据孢子的密度和脂肪酸生物标志物的浓度估算土壤中AM真菌的丰度。使用DNA测序和孢子鉴定测量根和土壤中AM真菌的多样性。土壤中AM真菌的丰度随着放牧和降水的增加而下降，并随着土壤磷的增加而增加。根和土壤中AM真菌DNA的群落组成不同。根样品具有更多与生物因子相关的AM真菌指示剂物种（寄主植物物种和放牧），而土壤样品具有更多与特定样品位点相关的指示剂物种。这些发现表明，区域性的水生条件决定了场所水平的物种库，植物物种从中主动选择通过放牧改良的根定殖真菌组合。将AM真菌丰度和群落组成的多次测量结合起来，可以最自然地评估自然生态系统中菌根真菌群落的结构。