IUCN Management Category Ia (Strict Nature Reserve) refers to those areas that receive the least amount of human impact. They are defined by IUCN as “strictly protected areas set aside to protect biodiversity and also possibly geological/geomorphological features, where human visitation, use and impacts are strictly controlled and limited to ensure protection of the conservation values”. ¹ The primary objective of protected areas in this category is to conserve regionally, nationally or globally outstanding ecosystems, species (occurrences or aggregations) and/or geodiversity features: these attributes will have been formed mostly or entirely by non-human forces and will be degraded or destroyed when subjected to all but very light human impact. Other objectives include to secure undisturbed examples of the natural environment for scientific studies and to conserve cultural values associated with nature.

Developed by the International Union for Conservation of Nature (IUCN) with support of the World Commission on Protected Areas (WCPA) and other international institutions such as the Convention on Biological Diversity (CBD), and assigned by national governments.

The current IUCN Categories were approved in 1994, and revised guidelines were published in 2008. ¹

Globally applicable.

The area should generally: ¹

• Have a largely complete set of expected native species in ecologically significant densities or be capable of returning them to such densities through natural processes or time limited interventions;
• Have a full set of expected native ecosystems, largely intact with intact ecological processes, or processes capable of being restored with minimal management intervention;
• Be free of significant direct intervention by modern humans that would compromise the specified conservation objectives for the area, which usually implies limiting access by people and excluding settlement;
• Not require substantial and on-going intervention to achieve its conservation objectives;
• Be surrounded when feasible by land uses that contribute to the achievement of the area’s specified conservation objectives
• Be suitable as a baseline monitoring site for monitoring the relative impact of human activities;
• Be managed for relatively low visitation by humans;
• Be capable of being managed to ensure minimal disturbance (especially relevant to marine environments).

These areas are managed for strict protection and this can be carried out by a range of actors depending on the governance type. See IUCN Protected Area Management Categories for information on governance types.

Legal and compliance – The classification of a Category Ia protected area requires that such areas are managed for conservation by legal or other effective means, and therefore legal recognition and protection at the national or sub-national level is likely to be present in these sites. The level of legal protection will however vary between countries, and will depend on the governance type of the area, as they receive differing levels of recognition by government in different countries. Nonetheless a number of national laws are likely to apply to these sites that deter economic activities in order to maintain the conservation values.

As designated protected areas, these sites receive international attention and have been incorporated into a number of environmental safeguard standards. These include those of multilateral financial institutions, such as but not limited to the World Bank ² and the International Finance Corporation ³. For details on environmental safeguard standards which are applicable to all protected areas, please see the Protected Areas page.

In addition, a number of sector specific safeguard standards refer to protected areas, many of which are related to certification programs, including the Roundtable on Sustainable Biomaterials (RSB) that declares categories I to IV as ‘no-go’ areas. ⁴ For details on certification programmes which are applicable to all protected areas, please see the Protected Areas page. 

Biodiversity importance – These areas are strictly protected for their biodiversity conservation values. While the actual biodiversity criteria used to identify and designate these sites will vary between countries and between areas, based on the level of protection afforded, high biodiversity values can be expected within these site-scale areas. They are therefore of high relevance for mitigating and avoiding risk from biodiversity loss.

Socio-cultural values – These areas are strictly protected from any form of human activity, and therefore the presence of socio-cultural values is unlikely due to a lack of human presence and intervention at sites. Nonetheless, these areas can be of religious or spiritual significance (such as a sacred natural site), in which case there may be sites within the area that can be visited by a limited number of people engaged in faith activities. ¹ Furthermore, these areas can form the core area of a larger area with multiple uses, and therefore can play an important role in maintaining resources utilised by communities in the wider landscape.