Strict Nature Reserve

A strict nature reserve (IUCN category Ia) or wilderness area (IUCN category Ib), is the highest category of protected area recognised by the World Commission on Protected Areas (WCPA), a body which is part of the International Union for Conservation of Nature (IUCN). These category I areas are the most stringently protected natural landscapes.

Strict nature reserves and wilderness areas are protected areas that are created and managed mainly for the purposes of research or for the protection of large, unspoiled areas of wilderness. Their primary purpose is the preservation of biodiversity and as essential reference areas for scientific work and environmental monitoring.

Usage and intrusion are strictly controlled. As a result, strict nature reserves often form the core zones, with wilderness areas acting as a buffer zone, similar to the concept used for national parks (which are IUCN category II), but also for UNESCO World Heritage Sites.

In Austria, only one area has been designated as an IUCN category I protected area:

In their national strategy for biological diversity out to 2020 published in 2007, the German Federal Government set the aim of allowing 2% of the area of Germany to develop naturally and in an undisturbed way into wilderness areas.

Officially created in the 1950s, Integral Biological Reserves (Réserves Biologiques Intégrales, RBI) were dedicated to man free ecosystem evolution, on the contrary of Managed Biological reserves (Réserves Biologiques Dirigées, RBD) where a specific management is applied to conserve vulnerable species or threatened habitats.

Integral Biological Reserves occurs in French State Forests or City Forests and are therefore managed by the National Forests Office. In such reserves, all harvests coupe are forbidden excepted exotic species elimination or track safety works to avoid fallen tree risk to visitors (already existing tracks in or on the edge of the reserve).

...
Wikipedia