Application of remote sensing for monitoring of vegetation in Wurzacher Ried moorland

The "Wurzacher Ried" (ca. 1715 ha) is a bog and fen site in southern Germany near Lake Constance. In 1989 it was awarded the "European Diploma" because of its international importance. Therefore some measures have been planned to regenerate the affected parts (e.g. by raising the groundwater table) and protect the undisturbed areas. The effects of the measures should be controlled by monitoring vegetation development. Because of the sensitivity of the bog vegetation it is aimed to realize monitoring by means of remote sensing. In 1994 three flights with aerial survey cameras were carried out in order to receive large scaled (1:2.000, 1:1.000, 1:500) images in colour-infrared (CIR) and true colour technique. The vegetation cover in the training areas was sampled simultaneously to the air photo night. The sampling methods differed from Blaun.Branquet approach to sampling of vegetation structure at different scales. The sampling data were compared to the structures and colours in the air photos and thus helped designing an interpretation key. It can be shown, that many important plant species (especially indicator species) and plant communities can be identified in large stale air photos. The best date for laking the photos proved to be late spring (begin of lune). At this phenological state many species did not grow yet, whilst other species (particularly members of the grass familiy) are green, so that they can be distinguished easily. The search for uncommon means of remote sensing such as helicopter models or airship was not successfull, because ail of them have important disadvantages e.g. high costs. As a result it turned out, that the large amount of data collected by means of air photos, which are hardly to be handled, will produce great problems. Therefore it seems useful to get as much data as possible stored, processed, handled and interpreted automatically i.e. by geographic information systems. Consequently we are intending to test airborne scanner data, which are primarily digital data and can be interpreted in a GIS more easily than air photos.