Limietberg is an important water catchment for the Breede and Berg rivers, which flow through the reserve and feed the Wemmershoek, Stettynskloof, Theewaterskloof and Voëlvlei dams.

Limietberg is covered in mountain fynbos, with some indigenous forest vegetation in the wetter areas. Alien trees, including black wattle, hakea and pine, have invaded sections of the reserve.

The reserve is home to dassies, klipspringers, baboons, as well as the seldom-seen caracal and leopard. Two endemic birds, the Cape sugarbird and the protea canary, inhabit the area. Visitors may also spot black eagles and various other raptors. Three endemic and increasingly threatened fish species occur in the Berg and Breede rivers. Trout was introduced to the area before the reserve was established.