Vegetation transitions of floating wetlands in a complex of turbaries between 1937 and 1989 as determined from aerial photographs with GIS

The transition from open water to a swamp forest of a complex of ponds in the Polder Westbroek (The Netherlands) in the period 1937–1989 is studied. Changes between structurally different vegetation types are determined using remote-sensing data and a Geographical Information System. The transition follows a clear pathway from open water throughPhragmites/Typha-dominated community andCarex-dominated vegetation, toAlnus-dominated vegetation. The rate of this transition shows strong correspondence to changes in local management, demonstrating the large human impacts on ecosystems in this area.