Status and Trends of Biodiversity
Given its situation in the zone of confluence of the Nearctic and Neotropical biogeographic regions, its very varied topography and climate, its long history of in situ evolution and the manipulation and domestication of plant populations and species by indigenous people, Mexico is one of the five foremost biologically “megadiverse” countries in the world: It has five of the eight principal terrestrial biomes, and has one of the greatest assemblages of ecosystem diversity anywhere on the planet – a facet of biodiversity shared only with China, India, Peru and Colombia. Mexico’s share of global biodiversity is estimated at between 10 to 12% of all species, on a land area representing only 1.5% that of the Earth’s total. Mexico is ranked 2nd in the world for the diversity of its reptiles (804 species – behind Australia, with 880), 3rd for its mammals (530 species, behind Indonesia and Brazil with 667 and 578 species respectively), and 4th for its amphibians (361 species). In all, Mexico’s terrestrial vertebrate fauna (i.e., not including fish) numbers over 2,800 species, of which 974 – almost one third – are endemic to the country (including 65% of amphibians and 57% of reptiles). Its known vascular flora numbers 23,522 species, although estimates put the total at closer to 31,000, of which between 50 to 60% (around 15,000) are endemic, although levels of endemicity are even higher for certain plant families (83% of species of Cactaceae, 66% of Asteraceae, 63% of Orquidaceae and 58% of Fabaceae, for example). The aquatic and marine environments are no less diverse, with an estimated 3,500 species of marine fish – a diversity surpassed only by the Asia-Pacific region, which is 20 times larger–, while the world’s second largest coral Barrier Reef is shared by the Caribbean coasts of Mexico and Belize. Over 2,200 species of freshwater fish are documented from Mexico, of which 32% are endemic. Mexico’s great cultural diversity, with at least 60 surviving indigenous languages, has always been closely associated with its environmental diversity, and the origin of agriculture in Mesoamerica and the domestication of at least 118 economically important plant species in Mexico are only two facets of the human contribution to the country’s biodiversity: Maize, beans, squash, cacao, tomatoes and the avocado were all domesticated here. Among current threats to Mexico’s biodiversity are deforestation for land use change (principally for agriculture, but urban, industrial and infrastructural development also contribute), forest fires, illegal logging and species over exploitation (including fisheries), with invasive species, climate change and other factors currently of lesser importance, but with potential for greater impact.
Number and Extent of Protected Areas
Mexico has 159 federal reserves, covering a total of 22,275,672 hectares, with Biosphere Reserves comprising around 50% of the total area. 77% of this total comprises terrestrial ecosystems, while the remaining 23% protects marine environments, including coral reefs and coastal habitats. Mexico also has 67 Ramsar sites for wetland protection, with a surface of more than 5 million hectares – the second country with highest number of wetlands of international importance in the world.
Percentage of Forest Cover
73% of Mexico’s total land surface, that is over 140 million of a total of 194.3 million hectares, is covered by natural vegetation. Of this, a little over 71 million hectares (36.5% of Mexico’s territory) is forested (ecosystems in which trees predominate), while the remainder is mostly desert scrub and natural grasslands. Of the forested area, over 33 million hectares comprises secondary forest, while over 37 million hectares is considered primary forest (equivalent to 19% of the total land surface of Mexico).