Megadiverse countries#Cancún initiative and declaration of like-minded megadiverse countries

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{{short description|Nation with extremely high biological diversity or many endemic species}}

File:Map of the megadiverse countries.svg]]

A megadiverse country is one of a group of nations that house the majority of Earth's species and high numbers of endemic species. Conservation International identified 17 megadiverse countries in 1998,{{cite web |url=http://www.environment.gov.au/soe/2001/publications/theme-reports/biodiversity/biodiversity01-3.html |title=Biodiversity Theme Report |last=Williams |first=J. |date=2001 |website=environment.gov.au |access-date=2019-10-02 |archive-url=https://web.archive.org/web/20081208141905/http://www.environment.gov.au/soe/2001/publications/theme-reports/biodiversity/biodiversity01-3.html |archive-date=2008-12-08 |url-status=dead}}{{Cite web |url=https://www.biodiversitya-z.org/content/megadiverse-countries |title=Megadiverse Countries definition| Biodiversity A-Z |website=biodiversitya-z.org}} all of which are located at least partially in tropical or subtropical regions.

Megadiversity means to exhibit great biodiversity. The main criterion for megadiverse countries is endemism at the level of species, genera and families. A megadiverse country must have at least 5,000 species of endemic plants and must border marine ecosystems.