High stocks, but slow recovery, of ecosystem carbon in southern oceanic tussock grasslands
Peat-forming large-tussock grasslands on oceanic and sub-Antarctic islands are fundamentally understudied in terms of carbon (C) storage. Here, we quantify both plant and soil C and nitrogen (N) storage for the large tussock grass Poa flabellata in the Falkland Islands, at its most northerly range....
| Published in: | Polar Biology |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
2017
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| Subjects: | |
| Online Access: | https://research.brighton.ac.uk/en/publications/bc578d2f-c5fd-4ccd-8c60-1aebed12e683 https://doi.org/10.1007/s00300-017-2084-5 |
| Summary: | Peat-forming large-tussock grasslands on oceanic and sub-Antarctic islands are fundamentally understudied in terms of carbon (C) storage. Here, we quantify both plant and soil C and nitrogen (N) storage for the large tussock grass Poa flabellata in the Falkland Islands, at its most northerly range. In this study, we adopt a spatially explicit sampling approach to accounting for tussock and inter-tussock (between tussocks) areas for three habitats; remnant stands (surviving clearance and overgrazing), restored stands (planted) and eroded bare peat sites. We found that remnant stands of P. flabellata have above-ground C densities of 49.8 ± 9.7 Mg C ha−1, equivalent to temperate and boreal forests. The majority of above-ground C is stored within the pedestal, a compact accumulation of dead leaves, rhizomes and roots. By surveying restored stands of increasing age we found that such C accrual may take longer than two decades. Soil C stocks were horizontally and vertically spatially variable and did not differ between habitat types. Plant and soil C and N stocks were strongly coupled identifying the important role of N availability for C accrual in this system. Scaling-up our results, planting tussock grass could accrue up to 0.9 million Mg C on a decadal timescale across the islands, yet the impact of replanting on soil C storage is likely to be more variable. Our results highlight the local and regional importance of large tussock grasslands as dense C stores and that land management and conservation of these communities needs to be more carbon-conscious. |
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