Biospheres and the IUCN classification  In 1996, the IUCN and MAB published a guideline for how to assess UNESCO biosphere reserves in the IUCN classification system. For that to work, the IUCN distinguish between the biosphere core, buffer, and transition zones, and also between each individual biosphere reserve. The most important feature for the assessment is the biosphere's management objective. Given that one of the main objectives of biospheres are scientific work, generally speaking, this would put biosphere core zones in the IUCN category I; either Ia (strict nature reserve) or Ib (wilderness area). Biosphere buffer zones would fall in category IV, V or VI and transition zones would be categorized as either V or VI if at all possible . 238x238px|León holds the greatest concentration of Biosphere Reserves in the World with nearly 17\% of the territory declared .
Biospheres and the IUCN classification 238x238px|Province of León in Spain holds the greatest concentration of Biosphere Reserves in the World with nearly 17\% of its territory declared. In 1996, the IUCN and MAB published a guideline for how to assess UNESCO biosphere reserves in the IUCN classification system. For that to work, the IUCN distinguish between the biosphere core, buffer, and transition zones, and also between each individual biosphere reserve. The most important feature for the assessment is the biosphere's management objective. Given that one of the main objectives of biospheres are scientific work, generally speaking, this would put biosphere core zones in the IUCN category I; either Ia (strict nature reserve) or Ib (wilderness area). Biosphere buffer zones would fall in category IV, V or VI and transition zones would be categorized as either V or VI if at all possible .
A
238x238px|Province of León in Spain holds the greatest concentration of Biosphere Reserves in the World with nearly 17\% of its territory declared.
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. 238x238px|León holds the greatest concentration of Biosphere Reserves in the World with nearly 17\% of the territory declared