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| Titel |
Impact of long-term drainage on summer groundwater flow patterns in the Mer Bleue peatland, Ontario, Canada |
| VerfasserIn |
B. J. Kopp, J. H. Fleckenstein, N. T. Roulet, E. Humphreys, J. Talbot, C. Blodau |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 17, no. 9 ; Nr. 17, no. 9 (2013-09-12), S.3485-3498 |
| Datensatznummer |
250085928
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| Publikation (Nr.) |
 copernicus.org/hess-17-3485-2013.pdf |
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| Zusammenfassung |
| Long-term impacts of drier conditions on the hydrology of northern peatlands
are poorly understood. We used long-term drainage near a historic drainage
ditch, separating an area from the main peatland, as an analogue for
long-term drying in a northern temperate bog. The objective was to identify
the impact of drier conditions on ecohydrological processes and groundwater
flow patterns in an area now forested and an area that maintained a bog-like
character. Groundwater flow patterns alternated between mostly downward flow
and occasionally upward flow in the bog area and were mostly
upward-orientated in the forested area, which suggested that there the flow
pattern had shifted from bog- to fen-like conditions. Flow patterns were in
agreement with changes in post-drainage hydraulic conductivities, storage
capacity of the peat and water table levels. Compared to the bog, hydraulic
conductivities in the forested area were one to three orders of magnitude
lower in the uppermost 0.75 m of peat (paired t test,
p < 0.05). Bulk density had increased and the water table level
was lower and more strongly fluctuating in the forested area. Our findings
suggest hydraulic gradients and flow patterns have changed due to increased
evapotranspiration and interception with the emergence of a tree cover. The
smaller size of the now-forested area relative to the remaining bog area
appeared to be important for the hydrological change. With the main Mer Bleue
bog as hinterland, enhanced runoff to the drainage channel had little effect
on hydrologic and vegetation patterns. In the cut-off, smaller, now forested
area pervasive changes in vegetation and hydrologic processes occurred. The
difference in response to local drainage raises questions about tipping
points with respect to the impact of drying on peatland ecosystems that need
to be addressed in future research. |
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