Location
The site covers 260 km long tract of the Bug River valley between the mouth of the Krzna River and Lake Zegrzynskie.

History and Landscape
Well-formed flood terraces occur in the river Bug valley. There also are numerous inland dunes, hills and sand-winded fields. The kem terraces cover many places at the edge of the valley. The remaining fragments of moraine landscape are diversified by smaller river valleys which are tributaries of the Bug River.

Ecosystem
The variety of natural habitats in this area is impressive. 16 types of habitats listed in Annex I of Habitat Directive have been identified here. At the bottom of the area, except the main riverbed, you can admire numerous water courses overgrown with water and swamp vegetation. Moreover, we can distinguish patches of reedbeds communities with Water Horsetail, Lakeshore Bulrush, Water Manngrass, Narrowleaf and Broadleaf Cattail and Branched Bur-reed. The riverside is overgrown with extremely valuable willow-poplar and elm-ash woodlands.

Marshy areas are situated mainly near the mouths of the Bug River tributaries and around the remaining fragments of old riverbeds. Major part of the valley is covered by dry, extensively used pastures and meadows (40 % of the area). Arable lands cover 30 % of the site and forests overgrown less than 20 % of it. The variety of natural habitats makes it home for various rare and endangered plant and animal species.

Among the most interesting plants one can list: Thesium Ebracteatum, Angelica Palustris, Ground Cedar, Silene Lithuanica, Anemona Silvestris, Twinflower, Lesser Rattlesnake Plantain.

The world of fauna in the area is also very rich especially in species connected with water-mud habitats. You can meet birds and mammals including: beavers, otters, wolves, White-tailed Eagle, Lesser Spotted Eagle, Black Stork, Common Crane, Corn Crake, Great Bittern and Eagle-owl.

The water fauna is so interesting. In riverbeds you can meet European Pond Turtle, Fire-bellied Toad and Great Crested Newt - all three species confirmed as priority species for the conservation of European nature.

River Bug is also home for rare and protected fish species for example: Golden Spined Loach, Goat Goby and White Finned Gudgeon.

Threats
The biggest threat to the natural values of the refuge are dams, especially those piled up near riverbeds. This leads to separating water courses from the main riverbed which causes them to become more shallow and overgrowing with all sort of vegetation. Cutting down riparian forests and regulation of small water bodies is also very damaging. Building up infrastructure for tourists coming to visit this unique region has also had negative influence for the natural values of the site.

Nature conservation
The site was included into the European program Natura 2000 as the site of community importance. The following forms of nature conservation exist within the site: Landscape Parks: Podlaski Przelom Bugu and Nadbuzanski, Nadbuzanski Area of Protected Landscape and nature reserves:

• Szwajcaria Podlaska - with landscape values including moisture broad leaved forests, riverside is willow-poplar woodlands and Bug water courses;
• Leg Debowy - forest including complex of old oak stands and rare oak riparian forest;
• Zabuze - forest-landscape protecting oak and oak-pine stands with vast Mount of monument trees;
• Przekop - forest protecting natural broad leaved forests;
• Wydma Molozewska - protecting fauna of the large piece of pastures changing into sandy beaches. Established in order to protect migrating bird species resting there;
• Skarpa Molozewska - floristic;
• Debniak - protecting natural oak forests;
• Kaliniak - forest;
• Kozki - ornithological includes old water courses and near grasslands communities.