Roy, Shamik ORCID: https://orcid.org/0000-0002-9916-5651 and Bagchi, Sumanta
(2022)
Large mammalian herbivores and the paradox of soil carbon in grazing ecosystems: Role of microbial decomposers and their enzymes.
Ecosystems, 25 (4).
pp. 976-988.
ISSN 1432-9840
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Abstract
Grazing is the dominant land use across the world, and large mammalian herbivores exert strong influence over biogeochemical cycles. Grazing ecosystems feature C-rich soils, even though herbivores consume a major fraction of plant production to reduce detrital input to soil. Yet, counter-intuitively, moderate grazing can promote net soil-C storage in many ecosystems compared to grazer-exclusion. We address this enigmatic influence of grazers on soil-C and test their indirect effect on proximate drivers of decomposition: microbial extracellular enzyme activity. We used a replicated long-term grazer-exclusion experiment to measure responses in above- and belowground plant biomass, soil-C stock, microbial biomass, labile/recalcitrant C pools and three enzymes relevant to the C-cycle: peroxidase—which initiates decomposition of recalcitrant matter, alongside beta-glucosidase and cellobiohydrolase—which act further downstream on more labile fractions. Consistent with other ecosystems, upto 12 years of herbivore exclusion did not increase soil-C in the fenced plots despite higher plant biomass and higher potential detrital C-inputs. Grazer-exclusion did not alter microbial biomass; peroxidase increased threefold and beta-glucosidase was doubled; cellobiohydrolase was unaffected. Grazer-exclusion also led to twofold increase in recalcitrant-C and in microbial respiration, but it did not influence labile-C. Structural equation models supported the hypothesis that grazing favours soil-C via its indirect effect on peroxidase, but they did not support that the effects can run in the opposite direction where soil-C affects enzymes. Grazer-mediated shifts in how microbes deploy enzymes emerge as a plausible mechanism that affects soil-C. These linkages may be important to maintain soil-C sequestration in drylands which support large mammalian herbivores.
Item Type: | Article |
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Uncontrolled Keywords: | carbon sequestration,decomposition,grassland,herbivory,lignin,soil organic matter,structural equation modelling (sem),ecology, evolution, behavior and systematics,ecology,environmental chemistry,sdg 15 - life on land ,/dk/atira/pure/subjectarea/asjc/1100/1105 |
Related URLs: | |
Depositing User: | LivePure Connector |
Date Deposited: | 14 Feb 2023 16:30 |
Last Modified: | 29 Jun 2023 15:31 |
URI: | https://ueaeprints.uea.ac.uk/id/eprint/91130 |
DOI: | 10.1007/s10021-021-00696-8 |
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