The river flows through the
East Carpathian Biosphere Reserve, with its basin area including both the
Uzh National Nature Park and
Poloniny National Park, as well as the
Stužica primeval beech forest in the
Bukovec Mountains, a UNESCO
World Heritage Site, representing some of the last remnants of the
virgin forest ecosystems that once covered much of
temperate Europe.
Beech or
fir forests predominate in the basin area, while
scrub beechwoods and
polonynas occur at higher elevations. Notable plant species include
Lady Josika's lilac (
Syringa josikaea), with many others listed in the
Red Data Book of Ukraine. The forest
canopy supports the
saproxylic alpine longhorn beetle (
Rosalia alpina). Wetland communities of birds and amphibians, such as the
Carpathian newt (
Lissotriton montandoni) are found along the middle course of the river. The basin is one of the few areas in Central Europe where three large carnivores,
brown bears,
Eurasian lynx, and
wolves coexist. The territory supports the
black stork and the
golden eagle. The river is home to
salmonid fish, including the
European grayling (
Thymallus thymallus), subject to local conservation protection, and historically provided habitat for the
Danube salmon (
Hucho hucho), now critically reduced across its native range. == Regions ==