Wetland Reconstruction By Controlling Water Level In Aamsveen: The Effects On Variation Of Vegetation And Nutrients

The wetlands play an important role in the ecosystems because they make the connection between water and land ecosystem. They also are essential to human well-being, and to flora and fauna. Any small change in wetlands may have considerable effects to the ecosystem.The study area is Aamsveen, a region managed by the Stichting Landschap Overijssel since 1967. The main objective of the research is the re-creation of favourable habitat conditions for the restoration of the native landscape: a raised peat bog. The last significant change in Aamsveen occurred in 2011 when the management closed old tubes and dug a new canal going around the wetland to restore the original steam of the Glanerbeek. Uncertainties regarding the impact of these changes have made it necessary to monitor the changes to groundwater level, vegetation and nutrients.The targets of this study are to monitor the following:(1) the change condition of groundwater level since 1995; the variation of vegetation between 2002 and 2012; and(3) the new canal’s purification capacity for nutrients. For the groundwater Table part, Global Polynomial Interpolation and statistical methods were used to explain the situation of groundwater. For the vegetation part, vegetation detection was produced from official maps of Landschap Overijssel, and remote sensing technology was applied to help us in the analysis of the growth condition of vegetation. For the nutrients part, due to the lack of previous data, field work was taken to measure the water quality of new canal and old canal in autumn.According vegetation change analysis, some of the vegetation changed because of the natural succession. The other change is minor, and could not be related significantly to groundwater changes. Due to groundwater level analysis, the difference of groundwater between the canal change before and after is smaller than the mapping accuracy. According water quality analysis, the new canal reduces a large part of the external nutritent load on the wetland. Since the results don’t show any apparent relation between groundwater level and vegetation changes, the comparison of groundwater level, vegetation, and nutrient distribution can’t be realized. Since natural reaction of the vegetation on smaller changes in the water regime takes several years, a longer period is needed after the diversion of the canal for identifying the actual effects.