Areas having essential value for the environmental, scientific, cultural and landscape reasons in natural or slightly changed - ecosystems, refuges and natural sites. They also protect habitats of plants, animals, fungi and formations and elements of inanimate nature.

Depending on the aim of the protection, the following types of nature reserves:
- forest (residues and fragments of primeval forests, forest community types, tree sites in their natural habitats);
- water (lake, river, stream, and sea waters along with plant communities and animal species);
- steppe (xerothermic grasslands, mainly on calcareous and gypsum soil);
- halophyte (seaside and inland halophytes);
- fauna (populations and habitats of mammals, birds, reptiles, amphibians, fish and invertebrates);
- flora (populations and habitats of species or species groups of cryptogams, flowers, mushrooms, and lichens);
- peat-bog (communities and species of lowmoor, transitional, and raised bogs);
- inanimate nature (geological outcrops, karst formations, soil, rock formations, caves, dripstone decorations, fossils, places of erosion and other processes shaping the Earth's surface, geological forms, dunes);
- landscape (landscape with natural features, typical of certain geographical regions, often with historical sites).

• Act of 16 April 2004 on Nature Protection
  Place of publication: (Dz. U. z 2023 r. poz. 1336, z późn. zm.)

• Protection of nature