Korytarz ekologiczny doliny Odry pdf

Summary
the bream) the natural living conditions for fish species are little changed and the river’s
species composition is relatively diverse and typical of large, lowland rivers.
Apart from the oxygenation and temperature, another factor that determines the changes
of certain fish species thriving is a necessary sprawning substrate. Most species of the
region of bream leaves spawn on plants, which can not be found in the regulated parts of the
river. This is why the sprawning grounds of those species are normally located on flood
plains, in backwaters or lower parts of tributaries. The presence of ox-bows or backwaters
has an important influence on the richness of their fish species. Except for serving as
sprawning grounds they are also important feeding, resting and nursery grounds. Deeper
ox-bows are used by many species as wintering grounds or a shelter in times when the state
of the river’s water quality has deteriorated.
The waters of the Oder are a permanent route for fish migration. Three situations are possible
here: i) the movement of species extinct in some parts of the Oder or its tributaries
who try to gain new habitats or return to the old ones, ii) the expansion of introduced or
accidentally imposed species, iii) migration of species between the catchment basins of the
Oder and the Vistula and the Oder and the Elbe.
The most valuable parts of the river Oder, in terms of ichthyofauna include:
• The Oder valley between the opening of Nysa K³odzka and Stobrawa, together with
ox-bows situated between levees. One can find here among others, barbel, which came
from the Nysa K³odzka after the load of pollutants in the Oder had dropped.
• Comples of ox-bows between the Oder and the O³awa (inlc. wells).
• Ox-bows between levees of the Oder, below Œcinawa to the confluence with the
Jezierzyca.
• Ox-bows near the confluence with the Barycz.
• Opening of the Bóbr River to the dam on Raduszcze reservoir. Currently the biggest
sprawning ground of the Oder population of vimba and sprawning ground of lampern.
• Area between the Oder and the Nysa £u¿ycka.
• Opening and lower stretches of the Pliszka and Ilanka Rivers (sprawning grounds of
rheophilous Ciprinidae, river trouts).
• Lower stretch of the Warta River, from the opening to the village of Witnica, with
diverse ox-bows, and the part of the Oder between the opening of the Warta and opening
of the Myœl.
• The Floodplain „Miêdzyodrze”.
Avifauna of the Oder valley
In general, the Oder river does not constitute an attractive site for breeding birds. However,
sites relatively unchanged from the natural state can still be found there, which makes possible
the nesting of species, such as: Kingfisher (Alcedo atthis), Sand Martin (Riparia riparia),
or Common Sandpiper (Actitis hypoleucos). These are areas situated close to the main current
of the river at the openings of tributaries, or following the stream on several kilometre
long distances. Although the Oder is deprived of sandy isles in the current and river bars,
which are so typical for the Vistula, similar composition of bird species can be found here in
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