Forbes, Bruce C.

Grosse, Guido

Göckede, Mathias

Macias-Fauria, Marc

Olofsson, Johan

Strauss, Jens

Ulrich, Mathias

Windirsch, Torben

Wolter, Juliane

Zimov, Nikita

English

In our study we examined the effects of large herbivorous animals on soil carbon storage in a permafrost landscape in northeastern Siberia. To assess the impact of those animals on the soil carbon storage, we examined soil profiles and permafrost cores from areas with different grazing intensities within landscape units, more specifically a drained thermokarst basin and the surrounding uplands. To do so, we chose our study sites in the Pleistocene Park near Chersky, as this area provides known animal densities and fenced areas, which allowed us to compare intensively grazed, extensively grazed, and non-grazed sites on a small spatial scale.
We found significantly higher carbon (TOC) values at those sites with intensive animal grazing, compared to non-grazed sites, especially within the active layer. Also, vegetation was shifted on intensively grazed sites from shrubby tundra vegetation to grasslands. In addition, active layer depth was smaller on grazed sites.
We conclude that the animals improve carbon storage and permafrost stability by changing the vegetation and removing or trampling down snow in winter, both of which led to colder ground conditions and hence reduced organic matter decomposition. This could be a hint to possible strategies to locally prevent permafrost thaw by rewilding or an intensification of animal husbandry in tundra areas

Forbes, Bruce C

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Study area• Kolyma lowlands, NE Siberia• drained thermokarst basin• Pleistocene Park MethodsField• AL: fixed volume cylinders@ soil profiles• PF: SIPRE augerLab• ice / water content• grain size composition• TOC• TN• δ13C• 14C dating• δ2H & δ18O frompore waterResults• 6x higher TOC in AL at intensively grazed sites• lower degree of decomposition of OMat intensively grazed sites• grassland vegetation, less shrubs under grazing impactImpacts of Large Herbivores on Permafrost Soil Carbon StorageIntensive grazing by large herbivorous animals increased soil carbon storage in theactive layer of a Siberian permafrost landscape significantly over a period of 22 years, while also reducing thaw depth.Torben Windirsch1,2, Guido Grosse1,2, Mathias Ulrich3, Bruce C. Forbes4, Mathias Göckede5, Juliane Wolter2, Marc Macias-Fauria6, Johan Olofsson7, Nikita Zimov8, and Jens Strauss11AWI, 2University of Potsdam, 3University of Leipzig, 4University of Lapland, 5MPI Jena, 6University of Oxford, 7Umeå University, 8Northeast Science StationContact:Torben.Windirsch@awi.de@PeCHEc_projectMost likely due to• snow removal in winter• vegetation disturbances & selective browsingNext stepscircumarctic comparison studiesRelated paper:Windirsch et al. „Large Herbivores Affecting Permafrost –Impacts of Grazing on Permafrost Soil Carbon Storage“, Biogeoscience Discussion, DOI: 10.5194/bg-2021-227, 2021(a) soil profile at DB-EX; (b) permafrost core fromDB-EX(a) (b)(b)(a)(a) Schematic depiction of the grazing setting with bare ground/vegetation (summer) and snow cover (winter); (b) TOC values over depth for non-grazed, extensively grazed and intensively grazed sites within a drained thermokarst basin

Impacts of Large Herbivores on Permafrost Soil Carbon Storage

https://epic.awi.de/id/eprint/56877/1/Windirsch_2021_Poster.pdf

Impacts of Large Herbivores on Permafrost Soil Carbon Storage

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