Korytarz ekologiczny doliny Odry pdf

Summary
place in two ways. In the first case, individuals of a certain species gradually, generation
after generation, occupy neighbouring areas or sites, thus moving slowly along the corridor.
In the second case, the corridor serves only for „rapid” migration of individuals either
because it is an unsuitable habitat for the breeding of a given species, or because all sites
appropriate for this purpose have already been occupied.
The best ecological corridors, those of linear character, stretching over tens or even hundreds
of kilometres were created by rivers and their valleys, therefore their progressing fragmentation
raises an understandable concern. Some stretches of certain rivers and their valleys
have remained relatively unchanged, close by resembling their natural character and
having high ecological value. Tracts of the largest Polish rivers: the Vistula and the Oder
have such value. The state of the Vistula is far more natural state, while in the case of the
Oder river valley ecosystems have been better preserved, as large patches of riverside carrs
were preserved during regulation works. Therefore our opinion is that everything should be
done to maintain the still existing areas of high natural value in the Oder valley and begin
the restoration of the ecological values of its degraded parts. This would enable the establishment
of a better-defined ecological corridor (stretching from the northern to the southern
end of Poland), being one of the two main axes of ESOCH, an Ecological System of Protected
Areas whose creation in Poland is now under way. Thanks to its location near
Poland’s western border it will also constitute an important element of EECONET (European
Ecological Network).
Physiographic description of the Oder valley
The part of the Oder valley which lies on Polish territory, is characterised by a significant
landscape differentiation resulting from the intersection of many different physiographic
units, which, in their turn, have a different geological structure, surface features and age. The
age differentiation of the stretches of the Oder valley is significant: the upper stretch from
the state border to the Œcinawa Depression was finally created after the continental glacier
created during the Oder glaciation period had withdrawn, about 300-280 thousand years ago,
while the reach between Siekierki and the mouth of Szczecin Bay is only 13-15,000 years
old.
Water resources and pollution of the Oder catchment area
The Oder catchment area covers 118 861 sq km (of which 10.8 per cent lies outside Polish
borders) and can be divided into three areas of distinct hydrographic characteristics: the
basin of the Upper and Middle Oder extending over 53 536 sq km, including 9 235 sq km
outside Polish borders; the basin of the Warta River, the main tributary of the Oder, covering
54 529 sq km and the Lower Oder basin (10 796 sq km, of which 3 548 sq km lies on German
territory).
Intensification of human economic activity in the catchment basin of the Oder, expressed
through the significant industrialization and urbanization of this area constitutes the main
threat to the water quality in this region. This is particularly visible in the Upper and Middle
Oder basin, where the most environmentally arduous industrial projects have been localized.
This has its reflection in the water quality of the Oder. Waters of the lowest unclassified
quality, are carried in the Upper and Middle Oder catchment area, while downstream
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