Carbon Storage in Alpine Mires: A Case Study From Platzertal (Austria)

Alpine peatlands play a crucial role in mountain watershed functions and services while supporting high biodiversity. Their reliance on cool and humid conditions makes them particularly vulnerable to climate change, including rising temperatures and decreasing precipitation, as well as human disturbance. Moreover, their carbon storage potential must be integrated into global climate models. However, alpine peatlands remain largely unrecorded, and their typically thin or absent peat layers leave their role as carbon reservoirs unclear. This study investigated carbon stocks in Platzertal, an alpine valley at 2,300 metres above sea level in the Ötztal Alps, Tyrol, Austria. The area features numerous small-sedge swamps spanning 7.11 hectares. The study site was divided into 143 sub-sites with an average area of 497 m². Peat volume, bulk density, dry weight and total organic carbon were analysed in 40 samples from these sub-sites. To achieve a comprehensive understanding of peat layer depth across the area, 666 plots were established to classify soil types and measure peat layers. The average peat layer depth was 11 cm, ranging from 5 to 100 cm. The carbon stock of the study area was calculated using the carbon density approach. The total area (7.11 hectares) of small-sedge swamp has a peat volume of 6,223 m³ and stores approximately 282 tons of carbon, equivalent to 1,036 tons of CO₂ in total or approximately 146 tons of CO₂ per hectare. These figures are significantly lower than those reported for other peatland regions, particularly the extensive boreal peatlands of the Northern Hemisphere. Our findings highlight that, whilst alpine peatlands have significant ecological importance and offer various ecosystem services, their contribution as soil carbon reservoirs is comparatively minor.