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Thesis Chapters by Oscar Andersson
Master's Thesis, 2022
This study combines a map study with a field study with the focus on wetland restoration. It inve... more This study combines a map study with a field study with the focus on wetland restoration. It investigates three restored wetlands in the forest of Gribskov and whether or not the restoration has been successful in bringing the wetlands back to historical, pre-ditching conditions. The historical conditions are investigated by analysing 19th century maps and by identifying peat in soil samples along transects. The current conditions are investigated through a current forest map and a GIS-based rain fill-model that identifies local depressions in the landscape, as well as measuring ground water depth in the field. The maps used for this study are also held up against each other and compared with the results of the field study to determine how well the delineation fits with the actual measured border of the wetlands.
An inclination analysis of the landscape surrounding the three restored wetlands was also made by a combination of field- and map studies for investigating whether or not the border of wetlands are affected by the topography of the surface.
The map study was also done to investigate the timing and intensity of the management actions that have led to the steep decline of wetlands in the whole of Gribskov through time, as well as the opposite trend in recent years.
An additional aspect of the field study dealt with the composition of soil horizons of the samples across the transects and across the three cases, revealing in what way soil constitutes change with increasing distance to a wetland.
It was found that all three studied cases seem to have been hydrologically well restored, as the correlation between a shallow depth of ground water and presence of peat was high, indicating that the border of the wetland is situated approximately at the same location currently as it did historically.
The inclination analysis was inconclusive, but vaguely supports the idea that topography do affect wetland borders. Method development is needed in order to reach more conclusive results in this matter.
Historical ditching was found to have had a great effect on the decline of wetlands, and modern restoration projects also seem to be an effective measure of bringing the wetlands back.
Lastly, the soil samples consistently showed a decrease of peat with increasing distance to blank water and an increase of inorganic mineral soil with increasing distance.
Master's Thesis, 2022
This study combines a map study with a field study with the focus on wetland restoration. It inve... more This study combines a map study with a field study with the focus on wetland restoration. It investigates three restored wetlands in the forest of Gribskov and whether or not the restoration has been successful in bringing the wetlands back to historical, pre-ditching conditions. The historical conditions are investigated by analysing 19th century maps and by identifying peat in soil samples along transects. The current conditions are investigated through a current forest map and a GIS-based rain fill-model that identifies local depressions in the landscape, as well as measuring ground water depth in the field. The maps used for this study are also held up against each other and compared with the results of the field study to determine how well the delineation fits with the actual measured border of the wetlands.
An inclination analysis of the landscape surrounding the three restored wetlands was also made by a combination of field- and map studies for investigating whether or not the border of wetlands are affected by the topography of the surface.
The map study was also done to investigate the timing and intensity of the management actions that have led to the steep decline of wetlands in the whole of Gribskov through time, as well as the opposite trend in recent years.
An additional aspect of the field study dealt with the composition of soil horizons of the samples across the transects and across the three cases, revealing in what way soil constitutes change with increasing distance to a wetland.
It was found that all three studied cases seem to have been hydrologically well restored, as the correlation between a shallow depth of ground water and presence of peat was high, indicating that the border of the wetland is situated approximately at the same location currently as it did historically.
The inclination analysis was inconclusive, but vaguely supports the idea that topography do affect wetland borders. Method development is needed in order to reach more conclusive results in this matter.
Historical ditching was found to have had a great effect on the decline of wetlands, and modern restoration projects also seem to be an effective measure of bringing the wetlands back.
Lastly, the soil samples consistently showed a decrease of peat with increasing distance to blank water and an increase of inorganic mineral soil with increasing distance.