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.
- 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 
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.
In Germany the following IUCN category I area has been designated:
- Königsbrücker Heide (IUCN Ib)
United States 
In the USA Wilderness Areas 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 cover an area of at least 20 km² (with the exception of islands) and may only be entered on foot, by canoe or on horseback. Exceptions are the extensive areas of wilderness in Alaska. At the beginning of 2010 there were over 750 recognised Wilderness Areas.
See also 
- Nigel Dudley (25 September 2012). Guidelines for applying protected area management categories (2008 , pdf in en, fr, es). IUCN. ISBN 978-2-8317-1086-0. Retrieved January 17, 2013.
- www.blickpunkt-brandenburg.de. Accessed on 11 Jun 2011.