The most important assets of the nature reserve are its population of wood ants (Formica aquilonia) that is one of the largest in Estonia, its versatile forest biocoenoses, and varying landscape. The purpose of the nature reserve is to protect the population of wood ants, other protected species, their habitats, forest biocoenoses, and Kärgandi kame field.
The total area of the reserve is 1,547 hectares. There are about 1,500 mounds on the territory of the nature reserve featuring various types of forests. The larger mounds are over 1.5 m high, and the diameter of the mounds is over 2.5 m.
The nature reserve is rich in different species of birds, including the lesser spotted eagle, the European roller, white-backed woodpecker, Eurasian eagle owl and capercaillie.