Mycorrhizal symbioses influence the trophic structure of the Serengeti

Abstract

Abstract1. It is known that tropical grasslands such as Serengeti host large populations of arbuscular mycorrhizal (AM) fungi and that they respond to abiotic and biotic factors.It is also known that AM symbioses are important for the uptake of essential plant nutrients, which, in turn, influences the biomass and nutritional quality of herbivores and their predators. The purpose of this study was to investigate the influence of AM symbioses on the biomass of different trophic levels of an ecosystem.2. To do this, we first measured the neutral lipid fatty acid biomarker 16:1ω5 to estimate the biomass of AM fungi in a long-term grazing exclusion experiment. Then, we used model selection of Bayesian linear regressions to infer the primary factors that influence AM fungal biomass. Using model selection of different combinations of soil characteristics, we selected the best model using the leave-one-out crossvalidation information criterion. Finally, we used the Madingley model to simulate the influence of AM fungi on higher trophic levels. We combined spatially explicit information about soil phosphorus and AM fungal biomass to explore the emergent patterns of the Serengeti resulting from AM symbioses.3. Our Bayesian analysis indicated that total soil phosphorus was the strongest predictor of AM fungal biomass, and there were significant interactions with grazing.Arbuscular mycorrhizal fungal biomass is lowest in soil where phosphorus is limited and increases with increasing phosphorus concentration. Biomass was also significantly higher in plots that were not grazed. The Madingley model indicated that nutritional benefits of AM symbioses maintain a substantial proportion of the biomass across all trophic levels. 4. Synthesis. Our analysis shows that inputs of phosphorus through arbuscular mycorrhizal symbioses substantially increase the ability of plants to grow and maintain nutritional quality, cascading through the biomass of consumers and predators in the ecosystem. Although they account for less than 1% of the total modelled biomass, the predicted nutritional benefit provided by arbuscular mycorrhizal fungi increased the biomass of macro-organisms in the Serengeti by 48%. When considering the management of biodiversity, future ecosystem models should account for the influence of arbuscular mycorrhizal fungi on all trophic levels.

Fungal Communities Resist Recovery in Sand Mine Restoration

“…Fungi are key determinants of soil physical, chemical and biological properties as they cycle nutrients, decompose organic matter, and form mycorrhizas with plants supporting their growth (De Boer et al, 2005;Gessner et al, 2010;Dickie et al, 2013). However, fungi are not considered or monitored in ecosystem restoration efforts as consistently as bacterial communities (Jones et al, 2018;Yan et al, 2018), despite the tight link between soil fungi and higher trophic levels (Stevens et al, 2018;Yan et al, 2018). Consideration of soil fungal communities is therefore an important aspect of successful sand mine restoration, but there are few guidelines for their successful restoration.…”

Plant–microbial interactions facilitate grassland species coexistence at the community level

“…Except for Lepidium apetalum , forbs tended to experience positive PMI. AM fungi typically promote plant growth in grasslands, and forbs generally receive more benefits from AM fungi than C 3 graminoids (Frouz et al , van der Heijden et al , Stevens et al ). Therefore, we propose benefits received by forbs may have been driven by AM fungi in our study.…”

Variations in the Compositions of Soil Bacterial and Fungal Communities Due to Microhabitat Effects Induced by Simulated Nitrogen Deposition of a Bamboo Forest in Wetland

“…Indeed, previous studies suggest that communities of arbuscular mycorrhizal fungi (AMF) are structured by soil properties [16,19,61]. Ordination of soil characteristics (mainly pH, silt, and sand) improved the predictions of AMF abundance but was not a significant contributor [62]. Soil type and texture correlated with AMF communities [63], possibly because AMF can increase plant uptake of nutrients [60].…”