The risk of carbon emissions from permafrost is linked to an increase in ground
temperature and thus in particular to thermal insulation by vegetation, soil layers
and snow cover. Ground insulation can be influenced by the presence of large
herbivores browsing for food in both winter and summer. In this study, we
examine the potential impact of large herbivore presence on the soil carbon
storage in a thermokarst landscape in northeastern Siberia. Our aim in this pilot
study is to conduct a first analysis on whether intensive large herbivore grazing
may slow or even reverse permafrost thaw by affecting thermal insulation
through modifying ground cover properties. As permafrost soil temperatures
are important for organic matter decomposition, we hypothesize that herbivory
disturbances lead to differences in ground-stored carbon. Therefore, we
analyzed five sites with a total of three different herbivore grazing intensities
on two landscape forms (drained thermokarst basin, Yedoma upland) in
Pleistocene Park near Chersky. We measured maximum thaw depth, total
organic carbon content, δ13C isotopes, carbon-nitrogen ratios, and sediment
grain-size composition as well as ice and water content for each site. We found
the thaw depth to be shallower and carbon storage to be higher in intensively
grazed areas compared to extensively and non-grazed sites in the same
thermokarst basin. First data show that intensive grazing leads to a more
stable thermal ground regime and thus to increased carbon storage in the
thermokarst deposits and active layer. However, the high carbon content found
within the upper 20 cm on intensively grazed sites could also indicate higher
carbon input rather than reduced decomposition, which requires further
studies including investigations of the hydrology and general ground
conditions existing prior to grazing introduction. We explain our findings by
intensive animal trampling in winter and vegetation changes, which
overcompensate summer ground warming. We conclude that grazing intensity—along with soil substrate and hydrologic conditions—might have a
measurable influence on the carbon storage in permafrost soils. Hence the
grazing effect should be further investigated for its potential as an actively
manageable instrument to reduce net carbon emission from permafrost.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:89849 |
| Date | 15 February 2024 |
| Creators | Windirsch, Torben, Grosse, Guido, Ulrich, Mathias, Forbes, Bruce C., Göckede, Mathias, Wolter, Juliane, Macias-Fauria, Marc, Olofsson, Johan, Zimov, Nikita, Strauss, Jens |
| Publisher | Frontiers Media S.A. |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 10.3389/fenvs.2022.893478 |
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