How animal-mediated mutualistic microbiomes modulate the environmental sensitivity of savanna carbon dynamics

Samenvatting

African savannas are special because their large role in the global carbon cycle and in regional nutrient cycles is strongly mediated by both vertebrate and invertebrate animals. Significant changes in carbon dynamics are predicted for savannas, because the soil decomposer microbiome and fire, the two main agents of organic matter mineralisation in most current carbon cycling models, are highly sensitive to predicted changes in climatic variability and land-use.
However, carbon release through mineralisation is not only performed by the free-living soil microbiome and fire, but also by mutualistic microbiomes that are hosted by large ungulate herbivores (gut microbiota) and termites (fungal colonies in mounds). These animal-mediated mutualisms should provide rather constant and favorable conditions to the microbial community “inside”, thereby disconnecting the decomposition process from periodical unfavorable abiotic conditions outside. Accounting for this special, animal-mediated decomposition pathways could radically change our understanding of the sensitivity of African savannas to increased environmental variability, and could strongly modify predictions about soil carbon sequestration and other ecosystem services, under current and future climate and landuse.
Building on previous work of the research team on the role of large herbivores and termites in savanna ecosystems, we will assess the relative importance of these alternative decomposition pathways and how they change the way that rainfall variability and human land-use affect carbon sequestration. Specifically, we will combine termite and large-herbivore exclosure experiments across environmental and land-use gradients with advanced techniques for diet and microbiome characterization (DNA-barcoding, high-throughput amplicon and shotgun sequencing).
This innovative analysis of the landscape-level role of animal-hosted, “sheltered” microbiomes will lead to more accurate predictions on the impact of environmental change on savanna carbon dynamics; and underpin practical solutions for reducing the sensitivity of ecosystem-scale carbon sequestration and nutrient cycling to increased climatic variability.

Kenmerken

Projectnummer

OCENW.KLEIN.014

Hoofdaanvrager

Prof. dr. J.H.C. Cornelissen

Verbonden aan

Vrije Universiteit Amsterdam, Faculteit der Bètawetenschappen (Faculty of Science), Systeemecologie

Looptijd

01/09/2019 tot 31/08/2022