Korytarz ekologiczny doliny Odry pdf

Korytarz ekologiczny doliny Odry
The number of areas and phenomena classified in those three categories, as well as the
level of their naturalness, formed a basis for the general evaluation of each of the nine tracts
of the Oder valley. Subsequently, as in the case of individual areas, three classes can be
applied to classify the parts of the valley in terms of their value, state of preservation of their
natural resources, and usefulness as an ecological corridor.
The valley reaches, classified as class I are characterised by a large number of areas of
category I, with a small share of areas from II and III categories, or urban areas which act as
barriers in the ecological corridor of the Oder and its valley. The are valley tracts with large
forest complexes, extensive wetlands and flood-meadows, large and abundant ox-bows,
flood terraces and distinct scarps on the valley wings. Also most areas protected by nature
reserves and landscape parks belong to this class. Those parts constitute the best-preserved
sections of the ecological corridor of the Oder and its valley.
The valley tracts belonging to class II are characterised by a predominance of the areas
of category II areas, with a small share of the category I and III areas. These tracts constitute
the sections of the ecological corridor that are of moderate value and require full
revitalisation on large fragments.
The valley reaches classified in class III are those where only small and isolated patches
of forests or flood-meadows are present. These stretches have frequent barriers, i.e. traffic
junctions and larger urban complexes, and constitute the weakest parts of the Oder valley
ecological corridor. Their quick and complex revitalisation is necessary, as it is to plan systems
to by-passing urban areas.
All stretches of the Oder have been categorized in one of three classes, also taking into
consideration the degree of the four basic components of an ecological corridor (river valley
forests, flood-meadows and wetlands, ox-bows, and forests growing on the edges of the valley).
The remaining three elements of a corridor (levees, drained meadows and the river
itself) were not considered in terms of division into stretches.
Racibórz Basin (class II) – the functioning of the ecological corridor in this part of the
valley is currently impossible. The restoration of this role requires rehabilitation of riverside
carrs and oak hornbeam forest on the most deforested fragments, with wet meadows on the
patches between them. The element which functions relatively well as an ecological corridor
is the forested area on the edges of the valley. The most dangerous ecological barrier is
constituted by the urban and industrial complex of the town of Kêdzierzyn-KoŸle, bridging
two river banks.
Wroc³aw Proglacial Stream Valley (class I). In this part of the valley the best functioning
fragment of the ecological corridor stretches between Narok and Lubi¹¿. In the upper
stretch of this tract it is necessary to restore, at least in some parts of the area, the riverside
carrs and oak hornbeam forests, as well as the wet meadows. The biggest ecological barrier
in this part of the Oder valley is the urban and industrial agglomeration of Wroc³aw. However,
quite significant number of parks and green belts in the city itself and along the canals
of the Oder minimizes, to some extent, the adverse impact of this barrier, so its effective
influence is limited to an 8-km long stretch of the Oder within the city centre.
214