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. Purpose 
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. IUCN category Ia strict nature reserves are generally established exclusively for scientific field work. IUCN category Ib wilderness areas are defined as "large unmodified or slightly modified areas, retaining their natural character and influence, without permanent or significant human habitation, which are protected and managed so as to preserve their natural condition." 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. Protected areas

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

 Urwald Rothwald (IUCN Ia) in the Wildnisgebiet Dürrenstein (Ib), Lower Austrian Eisenwurzen

British Indian Ocean Territory 
Parts of Diego Garcia and other islands in the British Indian Ocean Territory are protected as strict nature reserves. France
Officially created in the 1950s, Integral Biological Reserves (, RBI) were dedicated to man free ecosystem evolution, on the contrary of Managed Biological reserves (, 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). At the end of 2014, there were 60 Integral Biological Reserves in French State Forests for a total area of  and 10 in City Forests for a total of . Germany 
The German federal government's national strategy for biological diversity up to 2020 published in 2007 set the aim of allowing 2% of the area of Germany to develop naturally and in an undisturbed way into wilderness areas. United States 
In the U.S. wilderness areas (NWPS) are the strictest category of protected area. They are designated by law in accordance with the Wilderness Act of 1964 by the United States Congress. They must be large enough to adequately preserve their resources and may only be entered on foot, by canoe or on horseback. Limited exceptions are the extensive areas of wilderness in Alaska. There are over 800 recognised wilderness areas. Complete List of IUCN category 1a and 1b sites 
The complete list of countries (as of 2016) with IUCN category 1b sites can be found in the Management Guidelines for IUCN Category 1b (wilderness) Protected Areas. The most up-to-date resource is the Protected Planet World Database on Protected Areas, which can be searched by many filters including IUCN category levels and country. See also 
 IUCN protected area categories
 Natural landscape
 Wilderness

Sources 
 
 Casson, S. et al. (Ed.s). (2016). Wilderness Protected Areas: Management Guidelines for IUCN Category 1b (wilderness) Protected Areas

References

External links 
 IUCN - World Commission on Protected Areas (engl.) IUCN Protected Area Category 1b Management Guidelines, (engl.) IUCN-Schutzgebietskategorien (pdf)
 World Database of Protected Areas, UNEP-WCMC.org

Wilderness areas
Protected areas
Nature reserves