Location
The Zwolenka river valley (1934.6 ha.) is situated in mazowieckie voivodeship, near Radom. It includes following communes Chotcza, Przylek, Zwolen.

Ecosystem
The area has exceptional natural and landscape values. Every year in early spring the river valley is flooded and the river meanders, creates watercourses and peat-holes. Extremely valuable wet and dry habitats occur in Zwolenka valley. The area is dominated by agricultural habitats, they cover about 60% of the whole area. There are also lots of meadow habitats, scrubs communities and coniferous forests.

In flooded areas you can meet riparian forests and willow riverside scrubs, as well as four other types of habitats extremely important for Europe.

• xserothermic grassland (the most important the ones with significant orchid habitats);
• watercourses and others, euthrophic water bodies;
• lowland and mountain meadows used extensively;
• dry, mainland sand grassland.

Flora and fauna
The site is one of the richest and most valuable refuges of wetland fauna. The common species are: Round Leaved Sundew, Dwarf Everlast, Common Clubmoss, Bogbean, Yellow Pond Lilly, White Water Lilly, Floating Watermoss, European Cranberrybush.

The fauna of the habitat is rich in various species: 17 fishes, 10 amphibians and about 79 nesting birds. Worth of notice is invertebrate fauna represented by 25 dragonfly species, 21 land snails and 43 water snails.

The symbol of the site is European Pond Turtle extremely rare reptile in Poland. Among amphibians you can mention about: Yellow Bellied Toad, European Common Toad, European Greek Toad, European Spadefoot Toad, Moor Frog, Water Frog, Pool Frog, Marsh Frog, European Common Frog, Smooth Newt. Most valuable birds are: Marsh Harrier, Corn Crake, Black Tern, Common Kingfisher. Unique species of invertebrate fauna are: Narrow-mouthed Whorl Snail, Green Club Tailed Dragonfly, Lecorrhina pectoralis, Aeschna Viridis.

Threats
The greatest threats for natural values of the area are temporary and local pollution of waters of Zwolenka river and small water bodies (in holes after peat extraction) overgrowing of abandoned meadows and pastures by trees and bushes which causes elimination of woodlots.

Existing forms of nature conservation:

• Borowiec nature reserve
• Dolina Rzeki Zwoleńki Area of Protected Landscape
• Promotional Forest Complex of Lasy Puszczy Kozienickiej