Idiosyncratic responses to simulated herbivory by root fungal symbionts in a subarctic meadow

Minna-Maarit Kytöviita,Johan Olofsson

doi:10.1080/15230430.2021.1878738

Minna-Maarit Kytöviita, Johan Olofsson

Open Access

https://doi.org/10.1080/15230430.2021.1878738

Copy DOI

Abstract

ABSTRACT Plant-associated fungi have elementary roles in ecosystem productivity. There is little information on the interactions between arbuscular mycorrhizal (AM) fungal symbiosis, fine endophytic (FE) and dark septate endophytic (DSE) fungi, and their host plants in cold climate systems. In particular, the environmental filters potentially driving the relative abundance of these root symbionts remain unknown. We investigated the interlinkage of plant and belowground fungal responses to simulated herbivory (clipping, fertilization, and trampling) in a subarctic meadow system. AM and FE frequency in the two target plant roots, Potentilla crantzii and Saussurea alpina, was unaffected by simulated herbivory, highlighting the importance and resilience of arbuscule forming mycorrhizas in a range of environmental conditions. Fertilization and trampling increased DSE colonization in P. crantzii roots although generally P. crantzii performance was reduced in these plots. The idiosyncratic responses by DSE fungal frequency in the two host plants in our experiment indicate that the host plant identity has a pivotal role in the DSE fungus–plant outcome. DSE fungal frequency did not respond to environmental manipulations in a manner similar to arbuscular mycorrhizas, suggesting that they have a different role in plant ecology.

Highlights

Plant–herbivore and plant–fungi interactions are central in northern ecosystem functions
Herbivore management has been proposed as a tool to combat global climate change effects in cold climates (Olofsson and Post 2018)
The two common herbs studied responded to simulated grazing in a species-specific manner, high lighting the importance of species diversity within the herbaceous functional group

Summary

Introduction

Plant–herbivore and plant–fungi interactions are central in northern ecosystem functions. The predominant grazers, reindeer and caribou, affect plant community structure and ecosystem processes in subarctic ecosystems in a fundamental way (Olofsson, Stark, and Oksanen 2004; van der Wal 2006). Grazers affect microbial and plant performance by increasing readily available nutrients through urine and feces and by increasing soil temperature (Olofsson and Oksanen 2002; Olofsson, Stark, and Oksanen 2004; van der Wal and Brooker 2004; Barthelemy, Stark, and Olofsson 2015). Plant species have idiosyncratic effects on soil, giving rise to species-specific ecosystem effects (Eisenhauer et al 2011; Kos et al 2015; Heinen et al 2018). Plants house a large variety of fun gal symbionts that directly affect plant performance in a species-specific way (Munkvold et al 2004) and that may respond to grazing. Some fungal symbionts act synergistically with the host plant, whereas others may make contrasting contributions to plant nutrition as well as carbon and nitrogen turnover in the soil (Read and Perez-Moreno 2003)

Objectives

Methods

Conclusion