Disentangling the relative importance of spatio-temporal parameters and host specificity in shaping arbuscular mycorrhizal fungus communities in a temperate forest

Stavros D Veresoglou,Stefan Hempel,Magkdi Mola,Monika Wulf,Leonie Grünfeld

doi:10.1007/s00572-021-01041-6

Abstract

Many woody and herbaceous plants in temperate forests cannot establish and survive in the absence of mycorrhizal associations. Most temperate forests are dominated by ectomycorrhizal woody plant species, which implies that the carrying capacity of the habitat for arbuscular mycorrhizal fungi (AMF) is relatively low and AMF could in some cases experience a limitation of propagules. Here we address how the AMF community composition varied in a small temperate forest site in Germany in relation to time, space, two plant host species, and also with regard to the degree to which plots were covered with AMF-associating woody species. The AMF communities in our study were non-random. We observed that space had a greater impact on fungal community composition than either time, mycorrhizal state of the close-by woody species, or the identity of the host plant. The identity of the host plant was the only parameter that modified AMF richness in the roots. The set of parameters which we addressed has rarely been studied together, and the resulting ranking could ease prioritizing some of them to be included in future surveys. AMF are crucial for the establishment of understory plants in temperate forests, making it desirable to further explore how they vary in time and space.

Highlights

We present a spatio-temporal study at a forest site where we address the relative importance of (i) physical distance, (ii) sampling time, (iii) host
It is likely that the occurrence and density of arbuscular mycorrhizal (AM) woody plants facilitate the dispersal of Arbuscular mycorrhizal fungi (AMF) propagules and their availability to less dominant understorey AM plants
Richness only differed with host plant (n = 93, t = − 4.44, P < 0.0001; when we narrowed observations to those from the fourth harvest, the respective statistics were n = 43, t = − 3.14, P = 0.003; Fig. S3): Euonymus plants contained on average 8.2 AMF taxa, whereas Hedera plants contained 10.54

Summary

Introduction

It is likely that woody plants in such studies had strong effects on the understory because they had acted as islands of AMF propagules (Grünfeld et al 2019) If it is the presence of AMF-associating woody species which mainly shapes the regional pool of AMF species, compared to grasslands, we might expect a lower relative importance of host specificity across the understory plants because tree root systems are comparably much larger than those of understorey plants. We hypothesized (Hypothesis 2) that relative coverage of AMF-associating woody species would alter AMF community composition more than host specificity does We addressed these two hypotheses in a forest site in the Elbe-Weser region in North-West Germany which we monitored over 2 years, totalling four harvests of root material

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Results

Conclusion