Slow recovery of arbuscular mycorrhizal fungi and plant community after fungicide application: An eight-year experiment

Prepared by Hana Pánková, Tomáš Dostálek, Kristýna Vazačová & Zuzana Münzbergová

Dry grasslands represent one of the most species-rich communities in Europe with a high occurrence of rare species. Some of the grasslands were changed to agricultural fields with intensive application of fertilizers or pesticides. After their abandonment, the former fields may be recolonized by dry grassland species. However, the recovery is a slow process, and many rare plant species, typical for dry grassland habitats, are absent in the formerly abandoned fields even after several decades. One of the reasons for their absence should be changes in the soil biota caused by previous intensive agriculture. The key component of soil biota for the growth of rare grassland plant species are arbuscular mycorrhizal fungi. Arbuscular mycorrhizal fungi are microscopic soil organisms, which establish a reciprocal beneficial association with plants. They help to transport nutrients and water to the plant roots and protect them against pathogens by the production of special chemicals. These fungi may be suppressed by different agricultural practices including fungicide application. Many of rare grassland species are dependent on association with these fungi, and therefore they are not able to grow on former fields, where these fungi are missing. Additionally, such changes in soil biota improve growth of large grasses, which further suppress the performance of rare plant species.

In our study, we evaluated the recovery of plant communities and arbuscular mycorrhizal fungi in dry grasslands after fungicide application. Further, the grazing was implemented on the part of the area to simulate traditional management intervention used for support of plant biodiversity. We evaluated the occurrence of particular plant species and functionality of fungi every year.

The results showed that the effect of fungicide application on the functionality of fungi persisted five years after the last fungicide application on ungrazed parts of the area, and even the recovery of fungi after introducing the grazing management was not sufficient for recovery of the rare plants. Grazing led to the suppression of grasses, but forbs were still largely absent with only a few exceptions of good colonizers of open habitats. This suggests that the absence of rare species could be caused by changes in the composition of the fungal community or low availability of their seeds. Direct addition of seeds of the forbs and/or adding suitable arbuscular mycorrhizal fungi may thus be tested as possible methods to support the recovery of the dry grassland community.

This is a plain language summary for the paper of Pánková et al. published in the Journal of Vegetation Science (https://doi.org/10.1111/jvs.12656).