The long-term effect of grazing by livestock on sedimentation rates in salt marshes in the Netherlands and Germany
The rising sea level and increasing number of storm tides expected in the future is threatening low lying coastal areas. In the Netherlands and Germany the coast is protected by sea walls. In front of these sea walls we find salt marshes which were declared to be unique ecosystems. These are in danger to drown or erode in the future which means that a important habitat for rare plant and invertebrate species and an important feeding ground for migrating birds would be lost. In the past these areas survived times of sea level rise by expansion to higher areas which became new salt marshes. Nowadays sea walls make that impossible.
Recently many projects started to solve the question whether salt marshes along the coast of the Netherlands and Germany are able to cope with the rising sea level by sedimentation. Many processes are influencing the rate of sedimentation. One of these is the grazing intensity. Salt marshes were traditionally used for commercial livestock grazing in the past (cattle, sheep). Grazing was stopped in wide areas after the start of the National Park in Germany. Nowadays scientists agree, that the cessation of grazing leads to a loss in biodiversity, whereas intermediate grazing intensities lead to a high number of plant species.
We want to investigate the effect of grazing on long term sedimentation rates in different salt marshes in the Netherlands and Germany. Soil cores were taken and analysed for 137Cs and 210Pb in the LARI in Göttingen. The data allow us to calculate sedimentation rates for the last 30 to about 50 years and find out more about the long term effect of grazing on sedimentation rates.
The information will be used to help making decisions about future management strategies in these areas.