TY - JOUR
T1 - Mycorrhizal symbioses influence the trophic structure of the Serengeti
AU - Stevens, Bo Maxwell
AU - Propster, Jeffrey
AU - Wilson, Gail W.T.
AU - Abraham, Andrew
AU - Ridenour, Chase
AU - Doughty, Christopher
AU - Johnson, Nancy Collins
N1 - Funding Information:
A special thanks to Emilian Mayemba for his invaluable assistance in collecting the samples for this study and for his dedication to the maintenance of this valuable long-term experiment. Thanks to the Frankfurt Zoological Society for their technical assistance with our field work and to Tanzanian National Parks (TANAPA) and the Tanzanian Wildlife Institute Research Institute (TAWIRI) for permitting us to conduct this research. We are indebted to Derek Sonderegger for his guidance with the statistical analysis and to Anita Antoninka, Mike Allen, R. Michael Miller and Mark Ritchie for contributing data and helpful suggestions. The National Science Foundation provided funding for this work (DEB-0842327).
Publisher Copyright:
© 2018 The Authors. Journal of Ecology © 2018 British Ecological Society
PY - 2018/3
Y1 - 2018/3
N2 - 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.
AB - 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.
KW - Madingley model
KW - Serengeti National Park
KW - arbuscular mycorrhizas
KW - ecosystem function
KW - environmental gradients
KW - phosphorus
KW - trophic structure
KW - ungulate grazing
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U2 - 10.1111/1365-2745.12916
DO - 10.1111/1365-2745.12916
M3 - Article
AN - SCOPUS:85041950621
SN - 0022-0477
VL - 106
SP - 536
EP - 546
JO - Journal of Ecology
JF - Journal of Ecology
IS - 2
ER -