Mycorrhizal fungi associated with high soil N:P ratios are more likely to be lost upon conversion from grasslands to arable agriculture

•Mycorrhizal fungal taxa in grasslands and farmlands are compared.•Taxa prevailing at high N:P ratios in grasslands are reduced in farmlands.•This may correlate with mutualistic quality of AMF in agriculture.

Agriculture often leads to altered composition and reduced diversity of arbuscular mycorrhizal fungal (AMF) communities compared to natural grassland systems. However, the ecology of taxa that are lost in this transition has thus far not been well characterized. In this study we found that reduced or lost AMF taxa in farmlands were significantly stronger correlated with soil N:P ratio than a randomly sampled community; this indicates that taxa that prevail at high N:P ratio in grasslands are the ones most sensitive to agriculture. As a high N:P environment is also commonly argued to impose the highest AMF benefit to plants, the observation that those taxa are lost could indicate that agricultural fields are left with communities of reduced symbiotic quality.