a preserve in Spassk Raion, Riazan’ Oblast, in the southeastern part of the Meshchera Lowland, along the left bank of the Pra River.
The Oka Preserve was established in 1935 to preserve and restore the natural environment of Meshchera. In 1970 its area totaled 22,900 hectares (ha), including more than 18,000 ha of forest. The protected area covers 17,500 ha, including the flooded Oka meadows and the right bank of the Pra River. Pine forests with birch and a mixture of broad-leaved trees predominate. There also are oak groves, and swamps occupy considerable areas.
Common animals in the Oka Preserve include the elk, wild boar, fox, otter, ermine, marten, raccoon dog, muskrat, squirrel, bats, capercaillie, hazel hen, grouse, crane, ducks (mainly mallard and teals), great snipe, whole snipe, woodcock, black kite, and buzzard. The most common fishes are the perch, pike, crucian carp, ide, roach, silver bream, and European bream. Other mammals and birds encountered include the badger, mink, lynx, white-tailed eagle, and black stork. Also inhabiting the waters of the preserve are the Aspius aspius, pikeperch, sterlet, and sheatfish. The Japanese deer has been acclimatized to the region, and the beaver, which had left the Oka Preserve and spread throughout Meshchera, has been reacclimatized. Work on the restoration of a herd of bison (as of January 1974 they numbered 32) began in 1959.
The preserve has a center for tagging animals. Records are kept of game animals, the dynamics of the animals’ numbers, and the role of invertebrates in the forest biocenosis are being studied. The Oka Preserve has a museum.