 |
| Titel |
The short-term effects of ecological restoration on carbon dioxide fluxes from a Molinia caerulea dominated marginal upland blanket bog. |
| VerfasserIn |
Naomi Gatis, David Luscombe, Emilie Grand-Clement, Iain Hartley, Karen Anderson, Richard E. Brazier |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250092350
|
| Publikation (Nr.) |
 EGU/EGU2014-6686.pdf |
|
|
|
|
|
| Zusammenfassung |
| Peat soils in the UK represent a significant long-term carbon store. Despite this the annual
imbalance between uptake and release is small and susceptible to change in response to land
management, atmospheric deposition and climate change. The shallow marginal
peatlands of Exmoor, southwest England, have historically been subject to extensive
drainage and are known to be vulnerable to future changes in climate as they lie at the
southern edge of the ombrotrophic peatland climatic envelope. However little is
known about the processes that drive CO2 fluxes from degraded Molinia caerulea
dominated upland mires or the potential effect that restoration through drainage
blocking will have. The Mires-on-the-Moors project (www.upstreamthinking.org),
funded by South West Water aims to restore the eco-hydrological functionality
to over 2000 hectares of drained mire by April 2015. We hypothesised that such
mire restoration will return these upland mires to peat forming/carbon sequestering
systems.
Partitioned below-ground respiration fluxes as well as biotic and abiotic variables, were
collected on various dates in 2012 and 2013 along six transects adjacent to three pairs of
drainage ditches. One of each pair was restored by blocking with peat dams in spring
2013 whilst the other remained unrestored to act as a control. Monitoring locations
were arranged along transects to investigate the spatial variation in gas fluxes with
respect to the drainage ditches. By partitioning below-ground fluxes it was possible to
monitor root-derived (autotrophic) and more importantly soil-derived (heterotrophic)
respiration providing an insight to the effects of ditch blocking on the long term carbon
store.
Here we present CO2 fluxes for the growing seasons at two critical stages in the
restoration process: (a) immediately pre-restoration and (b) immediately post- restoration,
and discuss the temporally and spatially variable processes driving below-ground CO2 fluxes.
Respiration rates were comparatively low in these shallow humified peats, with
daily mean total, heterotrophic and autotrophic respiration reached 1.34, 0.60 and
0.23 μmolCm-2s-1 respectively. As expected soil temperature had a significant
control on respiration rates, once this was accounted for water level showed a weak
effect on total and heterotrophic respiration. Distinguishing the effects of ecological
restoration between a wetter baseline period and a drier post-restoration period
had its challenges. However, by expressing the respiration rates in the restored
sites as a proportion of that observed in the control sites, the confounding effect
of climate variability could be accounted for. This allowed us to determine that
heterotrophic respiration decreased at the restored sites comparative to the control sites
following restoration, indicating the immediate effect of restoration was to reduce
decomposition of the peat store, with implications for carbon sequestration rates. |
|
|
|
|
|
|