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Title: Carbon dynamics within an upland heath
Author: Quin, Samuel L. O.
ISNI:       0000 0004 2737 5371
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2012
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Upland heath is an extensive habitat in the UK and is currently managed for a range of objectives; agricultural grazing, sporting interests and biodiversity conservation. Future land management will also have to address the provision of the ecosystem service of carbon sequestration. Using a combination of short and longer term monitoring and field manipulation experiments this thesis investigates the carbon sequestration potential of two upland heath vegetation communities, one dominated by Calluna vulgaris (L.) Hull (Calluna), the other by graminoids. These typically occur as a result of low and high intensity grazing and burning regimes respectively. Studies include; (1) a 13C tracer experiment to compare the rate of carbon assimilation and the fate of assimilated carbon over six weeks during the growing season in the two communities; (2) a moss removal experiment to investigate the impact of the moss layer on carbon dynamics in the two communities; (3) a one-year CO2 flux study to estimate the annual carbon sequestration of each community; and (4) a study comparing the carbon storage (above and below-ground) and soil respiration rates between degraded graminoid upland heath that was formerly dwarf-shrub upland heath, restored upland heath now dominated by dwarf shrubs, and long-established, Calluna-dominated upland heath. Despite contrasting plant functional traits, similar short term carbon cycling was observed in both communities. It was also shown that the moss layer, which is common to many upland heath habitats, can influence carbon cycling, more so within graminoid-dominated areas. On a longer time frame, a carbon benefit of a Calluna-dominated community over a graminoid-dominated community was observed. This was evident in a higher annual net ecosystem exchange of CO2 and larger stock of carbon in above- and below-ground carbon pools in a community dominated by Calluna. Greater respiration associated with the higher inherent metabolic rate of graminoids, and the large resistant carbon pool attributed to the woody nature of Calluna, are likely key factors explaining this difference. It is concluded that maintenance of a Calluna-dominated community and restoration of degraded areas of upland heath would represent positive management for carbon sequestration. It is further proposed that the amount of carbon saved via restoration, could be significant enough to warrant future investigations into this land management activity being included under the UK national greenhouse gas budget. This will help the UK reach its greenhouse gas emission reduction target set under the Kyoto Protocol.
Supervisor: Not available Sponsor: Scottish Natural Heritage ; James Hutton Institute
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available