Mycorrhizal symbioses influence the trophic structure of the Serengeti

Bo Maxwell Stevens, Jeffrey Propster, Gail W.T. Wilson, Andrew Abraham, Chase Ridenour, Christopher Doughty, Nancy Johnson

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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. 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 cross-validation 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. 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. 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.

Original languageEnglish (US)
Pages (from-to)536-546
Number of pages11
JournalJournal of Ecology
Volume106
Issue number2
DOIs
StatePublished - Mar 1 2018

Fingerprint

trophic structure
symbiosis
biomass
mycorrhizal fungi
trophic level
fungus
phosphorus
ecosystems
ecosystem
soil
grazing
nutritive value
tropical grasslands
predator
exclusion experiment
predators
Bayesian analysis
biotic factor
Bayesian theory
biomarker

Keywords

  • arbuscular mycorrhizas
  • ecosystem function
  • environmental gradients
  • Madingley model
  • phosphorus
  • Serengeti National Park
  • trophic structure
  • ungulate grazing

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Plant Science

Cite this

Stevens, B. M., Propster, J., Wilson, G. W. T., Abraham, A., Ridenour, C., Doughty, C., & Johnson, N. (2018). Mycorrhizal symbioses influence the trophic structure of the Serengeti. Journal of Ecology, 106(2), 536-546. https://doi.org/10.1111/1365-2745.12916

Mycorrhizal symbioses influence the trophic structure of the Serengeti. / Stevens, Bo Maxwell; Propster, Jeffrey; Wilson, Gail W.T.; Abraham, Andrew; Ridenour, Chase; Doughty, Christopher; Johnson, Nancy.

In: Journal of Ecology, Vol. 106, No. 2, 01.03.2018, p. 536-546.

Research output: Contribution to journalArticle

Stevens, BM, Propster, J, Wilson, GWT, Abraham, A, Ridenour, C, Doughty, C & Johnson, N 2018, 'Mycorrhizal symbioses influence the trophic structure of the Serengeti', Journal of Ecology, vol. 106, no. 2, pp. 536-546. https://doi.org/10.1111/1365-2745.12916
Stevens BM, Propster J, Wilson GWT, Abraham A, Ridenour C, Doughty C et al. Mycorrhizal symbioses influence the trophic structure of the Serengeti. Journal of Ecology. 2018 Mar 1;106(2):536-546. https://doi.org/10.1111/1365-2745.12916
Stevens, Bo Maxwell ; Propster, Jeffrey ; Wilson, Gail W.T. ; Abraham, Andrew ; Ridenour, Chase ; Doughty, Christopher ; Johnson, Nancy. / Mycorrhizal symbioses influence the trophic structure of the Serengeti. In: Journal of Ecology. 2018 ; Vol. 106, No. 2. pp. 536-546.
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