The Biała Tarnowska River Valley is an important ecological corridor of both regional and national importance. It provides connectivity between Natura 2000 areas of the Alpine and continental ecoregions. It affords the possibility of spreading to many species of plants, and also allows numerous animals to migrate.
Due to high biodiversity, the river has been included in the European Natura 2000 network. The upper part of the valley above the village of Florynka is a bird refuge of the Low Beskids (PLB180002). Practically the whole riverbed and coastal floodplains of Biala are within the refuge habitats of Biala Tarnowska (area code PLH120090).
The Biała Tarnowska River is a right-bank tributary of the Dunajec. It took its name from the ground through which it flows – a marl of light, creamy color. The river is 101.8 km long, and its catchment area is about 983.3 km2. The sources are in the Low Beskids on the northeastern slope of Lackowa Mountain, in the central part of the Polish Flysch Carpathians near the village of Ropki. Its main left-bank tributaries are: Banica, Czyrnianka, Mostysza (Florynka), Binczarówka, Pławianka, Wojnarówka, Brzanka, Jastrzębianka, Kipsznianka, Mesznianka, Rychwałdzianka, Rzuchowianka, and Zimna Woda. The most important right-bank tributaries are: Lipka, Czertyżnianka, Stukajanka, Czarna, Sudoł, Polnianka, Stróżnianka, Zborowianka, Ostruszanka, Rzepianka, Rostówka, Szwedka, Radlanka, Dębnica, Wątok, Stary Wątok and Chyszowski Rów.
Within the Biała Tarnowska catchment area three distinct parts can be distinguished:
- southern – with a mountain pattern, mostly forested, lying within the Low Beskids, accounting for about 25% of the catchment area;
- central – with a foothill relief, with deep river valleys cutting through deforested and mainly agricultural hills of the Rożnowskie and Ciężkowickie Foothills, constituting almost 70% of the entire catchment area;
- northern – covering the estuary section of the Biała Tarnowska valley and low hills within the Sandomierska Valley, constituting about 5% of the catchment area.
In the southern part, especially in deforested areas, in the upper parts quite often there is deep erosion of the riverbed, while in the lower sections there are sandbanks and gravel islands. The physicochemical parameters of the water in Biała Tarnowska, from the town of Grybów to the estuary section, are at the level III quality, and in the estuary section at level IV, mainly due to the amount of total suspension, phosphorus and BOD5 indicator.
Anthropogenic degradation has been observed in the Biała Valley for many years. The hydrotechnical buildings in the riverbed impaired the ecosystem by disrupting geomorphological and biological continuity as well as the structure of plant and animal assemblies. River and riverine habitats have changed, they have been defragmented and rebuilt, preventing migration of both fish and other water-dependent organisms. Human activity has reduced not only the natural beauty, but also utility values of the Biała Tarnowska River. Permanent indentation of its trough (vertical erosion) is the result of, among others things, an increase of river transport capacity caused by regulatory works increasing its unit slope. As a result of the straightening of the river, while narrowing its bed and reducing the supply of dragged debris from the higher sections, the granulation of gravel and the proportion of mud fractions changed. Erosion has increased and is still increasing by systematic stealing of gravel from the river. As a consequence, it negatively affected the ecological status and water quality. As a result, Biała Tarnowska was classified as having heavily changed rivers and the existing hydrotechnical buildings on the river contributed to breaking the ecological corridor.
Plant and animal species
There are many valuable plant and animal species in the Biała Valley. In the upper reaches, the river crosses patches of forest habitats and arable land or meadows. In the lower parts of the river, riverside alders appear, forming a subtype of alluvial forests. On the section between Śnietnica and Brunary there are riparian habitats associated with gravel bars. The river meanders on this section, creates rocky islands in the current. These places are occupied by three natural habitats: the initial stages of overgrowing of riverside stones, scrubs of coastal German Tamarisk and willow thickets. The occurrence of a rare German tamarisk (Myricaria germanica) is particularly important. After all, there are many valuable plant and animal species in the Biała Valley. Upstream, the river crosses patches of forest habitats and arable land or meadows. In the lower parts of the river, riverside alders appear, forming a subtype of alluvial forests. On the section between the villages of Śnietnica and Brunary there are riverside habitats associated with gravel point bars. The river meanders on this section, creating gravel islands in the river channel. In these places there are three types of habitats: initial stages of overgrowing of riverside stones, scrubs of German gravel tamarisk and willow thickets. The occurrence of a rare German tamarisk is particularly important.
The river stretch from Brunary to Florynka is a place where willow thickets can be found, without the bitter willow (Salix eleagnos). In some places, there are patches of older thickets or forest, with the participation of gray alder, Prunus padus, known as bird cherry, sycamore (Acer pseudoplatanus), ash (Fraxinus) and elm (Ulmus sp). In the further away, lower course of the river, the thicket and forest patches assume the character of typical riverside willow riparian forests mixed with alder, mixed with sycamore and elm. Alluvial forests and vegetation of mountain streams gravel bars (willow German tamarisk shrubs) are protected.
16 species of fish were found in Biała Tarnowska. The dominant species are common minnows, chub and Carpathian barbel. Upstream live brown trout. Other species are grayling, alpine bullhead, Stone loach, vimba bream (Vimba vimba), common nase, spirlin (Alburnoides bipunctatus). Biała Tarnowska is considered one of the most important migratory fish spawning grounds in the Vistula basin and is included in a restitution program of diadromic fishes. The river was restocked (unsuccessfully so far), by salmon and sea trout. On the Biała River one can also find bird species typical for this type of habitats, among others: common ringed plover, common sandpiper, northern lapwings, gulls, wagtails, swallows, common tern, mallards, gray herons.
Otters and beavers also occur in the Biała Tarnowska Valley, especially downriver.
Endangered species of fish (barbel, asp and salmon), amphibians (the yellow-bellied toad and crested newt), birds (e.g. golden eagle, storks, numerous species of woodpeckers and corn crake) and mammals – bats, like the lesser horseshoe bat (Rhinolophus hipposideros) and greater mouse-eared bat are associated with the river. In Bobowa village there are bat refuges around the hill Bukowiec (PLH120020).
All activities carried out under the project are part of both the Water and Environmental Program for Poland and the provisions of the Water Framework Directive (2000/60 / EC) and the Habitats Directive (1992/43 / EEC). As a result of their implementation, the connectivity of plant and animal habitats will be restored, and the Biała Tarnowska River will be able to fulfill the role of an ecological corridor for both aquatic organisms and those found in its valley, e.g. in thickets of riparian zone.