Understanding the distribution of plant mycorrhizal traits of the European flora should guide us to keep understanding and to expand our curiosity about the ecological roles and distribution of the mycorrhizal symbioses in plant communities. For instance, knowing that the proportion of AM plant species decreases at higher latitudes, may support previous hypotheses about AM symbioses claiming to be inefficient in cold conditions. As well, knowing that obligately mycorrhizal plants are poorly distributed in higher latitudes but not so poorly distributed at higher elevations and lower latitudes, open the hypothesis about the effect of glaciation on the distribution of plant mycorrhizal traits.

Guillermo Bueno within the research group of Martin Zobel and Mari Moora, and with several collaborators from the University of Tartu, as well as with Prof. Ingolf Kühn (Helmholtz-Centre for Environmental Research, Halle, Germany) present in essence the first attempt to analyze the distribution of plant mycorrhizal traits at the European level.

Citation: Bueno, C. G., Moora, M., Gerz, M., Davison, J., Öpik, M., Pärtel, M., Helm, A., Ronk, A. Kühn, I. & Zobel, M. (2017). Plant mycorrhizal status, but not type, shifts with latitude and elevation in Europe. Global Ecology and Biogeography. https://doi.org/10.1111/geb.12582 (link to full text)

Latitudinal trends of plant mycorrhizal types on the left, and the distribution of the proportions of obligately mycorrhizal plant species in Europe on the right

Abstract:

Aim

Identifying the factors that drive large-scale patterns of biotic interaction is fundamental for understanding how communities respond to changing environmental conditions. Mycorrhizal symbiosis is a key interaction between fungi and most vascular plants. Whether plants are obligately (OM) or facultatively (FM) mycorrhizal, and which mycorrhizal type they form – arbuscular mycorrhizal (AM), ectomycorrhizal (ECM), ericoid mycorrhizal (ERM) or non-mycorrhizal (NM) – can have strong implications for plant species distribution at the continental scale and on the responses of plants to environmental gradients.

Location

Europe, north of 43° latitude and excluding Russia, Belarus and Moldova.

Methods

Using published sources, we compiled the most complete dataset yet of plant mycorrhizal and geographical information for Europe, comprising 1442 plant species. We mapped the European distributions of plant mycorrhizal status (OM and FM) and type (AM, ECM, ERM and NM) and analysed their relationships with climatic, edaphic and plant productivity drivers on a 50 km × 50 km equal-area grid.

Results

The distribution of mycorrhizal types in Europe was driven by mean temperature, soil pH and productivity. AM plant species predominated throughout the region, but at higher latitudes the share of NM and, to a lesser extent, ECM and ERM species increased. FM species predominated over OM species, and this increased with latitude and was dependent on temperature drivers. The high share of OM species in the central European mountains indicates a possible influence of historical glacial refugia.

Main conclusions

Our results challenge the prevailing view of parallel trends in the latitudinal and elevational distribution of mycorrhizal types and demonstrate distinctive responses of plants with different mycorrhizal status to climatic, edaphic and biogeographical drivers at the European scale.