Schutz- und Pflegestrategien für Auenoberflächengewässer des Biosphärenreservates „Mittlere Elbe“

Abstract

LANGHEINRICH, U.; DOROW, S.; LÜDERITZ, V.: Strategies for protection and conservation of surface watersin floodplain landscapes of the Middle Elbe Biosphere Reserve. - Hercynia 35: 17-35.The landscape along the middle reaches of the Elbe river contains a diverse and ecologically-rich mixof floodplain and riverine habitats. Dynamic processes are constantly altering the face of this landscape– some natural, others result from human activities. To ensure the conservation of biocoenoses in theMiddle Elbe region, and the sustainable use of its resources, intervention into the altered and naturalprocesses shaping the landscapes is necessary. Current problems on the Elbe include erosion of theriver bed in certain stretches, loss of existing backwaters through successional processes and preventionof the development of new backwaters due to the artificial stabilization of the river banks.All of these problems have led to a reduction or even loss of natural floodplain structures and processesespecially to a loss of backwaters in early stadiums of succession. Actually, in the Middle Elbe BiosphereReserve only a few backwaters remained in a natural and ecologically rich status. Such waterbodieslike lake Sarensee and lake Crassensee are evaluated with a conservation index of 9 (nationallyimportant). They serve as refuges for re-settlement of restored waterbodies. In our case, restorationwas done by removal of mud from lake Wallwitzsee and lake Kühnauer See and by diversifyinghydroecomorphological structures in the ditch Landeskulturgraben. Beginning from the revitalizationthat led to an important increase of water quality, species number of macroinvertebrates and plantsincreased steadily. Actually, 45 % of mayflies, 54 % of caddisflies, 74 % of dragonflies, and 78 % ofwater snails that occur in the Elbe landscape are also present in the five natural or restored waterbodiesof this study. Among them there are altogether 91 endangered species. 18 of them are endangered byextinction. Conclusions from these former measures were used in 2001 to restore the backwater AlteElbe near Klieken and to reconnect a former Elbe meander to the river.