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

Abstract

LANGHEINRICH, U.; DOROW, S.; LÜDERITZ, V.: Strategies for protection and conservation of surface waters
in 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 mix
of 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 the
Middle Elbe region, and the sustainable use of its resources, intervention into the altered and natural
processes shaping the landscapes is necessary. Current problems on the Elbe include erosion of the
river bed in certain stretches, loss of existing backwaters through successional processes and prevention
of 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 processes
especially to a loss of backwaters in early stadiums of succession. Actually, in the Middle Elbe Biosphere
Reserve only a few backwaters remained in a natural and ecologically rich status. Such waterbodies
like lake Sarensee and lake Crassensee are evaluated with a conservation index of 9 (nationally
important). They serve as refuges for re-settlement of restored waterbodies. In our case, restoration
was done by removal of mud from lake Wallwitzsee and lake Kühnauer See and by diversifying
hydroecomorphological structures in the ditch Landeskulturgraben. Beginning from the revitalization
that led to an important increase of water quality, species number of macroinvertebrates and plants
increased steadily. Actually, 45 % of mayflies, 54 % of caddisflies, 74 % of dragonflies, and 78 % of
water snails that occur in the Elbe landscape are also present in the five natural or restored waterbodies
of this study. Among them there are altogether 91 endangered species. 18 of them are endangered by
extinction. Conclusions from these former measures were used in 2001 to restore the backwater Alte
Elbe near Klieken and to reconnect a former Elbe meander to the river.