Map of the world's biodiversity hot spots, all of which are heavily threatened by habitat loss and degradation
Abiodiversity hotspot is abiogeographic region with significant levels ofbiodiversity that is threatened by human habitation.[1][2][3]Norman Myers wrote about the concept in two articles inThe Environmentalist in 1988[4] and 1990,[5] after which the concept was revised following thorough analysis by Myers and others into "Hotspots: Earth's Biologically Richest and Most Endangered Terrestrial Ecoregions"[6] and a paper published in the journalNature, both in 2000.[7]
To qualify as a biodiversity hotspot on Myers' 2000 edition of the hotspot map, a region must meet two strict criteria: it must contain at least 1,500 species ofvascular plants (more than 0.5% of the world's total) asendemics, and it has to have lost at least 70% of its primary vegetation.[7] Globally, 36 zones qualify under this definition.[8] These sites support nearly 60% of the world's plant, bird, mammal, reptile, and amphibianspecies, with a high share of those species as endemics. Some of these hotspots support up to 15,000 endemic plant species, and some have lost up to 95% of their natural habitat.[8]
Biodiversity hotspots host their diverse ecosystems on just 2.4% of the planet's surface.[2] Ten hotspots were originally identified by Myer;[1] the current 36 used to cover more than 15.7% of all the land but have lost around 85% of their area.[9] Thisloss of habitat is why approximately 60% of the world's terrestrial life lives on only 2.4% of the land surface area. Caribbean Islands like Haiti and Jamaica are facing serious pressures on the populations of endemic plants and vertebrates as a result of rapid deforestation. Other areas include the Tropical Andes, Philippines, Mesoamerica, and Sundaland, which, under the current levels at which deforestation is occurring, will likely lose most of their plant and vertebrate species.[10]
Only a small percentage of the total land area within biodiversity hotspots is now protected. Several international organizations are working to conserve biodiversity hotspots.
Critical Ecosystem Partnership Fund (CEPF) is a global program that provides funding and technical assistance to nongovernmental organizations in order to protect the Earth's richest regions of plant and animal diversity, including biodiversity hotspots, high-biodiversity wilderness areas and important marine regions.
TheWorld Wide Fund for Nature has devised a system called the "Global 200 Ecoregions", the aim of which is to select priority ecoregions for conservation from fourteen terrestrial, three freshwater, and four marine habitat types. They are chosen for species richness, endemism, taxonomic uniqueness, unusual ecological or evolutionary phenomena, and global rarity. All biodiversity hotspots contain at least one Global 200 Ecoregion.
Birdlife International has identified 218 "Endemic Bird Areas" (EBAs) each of which holds two or more bird species found nowhere else. Birdlife International has identified more than 11,000 Important Bird Areas[11] all over the world.
Alliance for Zero Extinction is an initiative of scientific organizations and conservation groups who co-operate to focus on the most threatened endemic species of the world. They have identified 595 sites, including manyBirdlife's Important Bird Areas.
TheNational Geographic Society has prepared a world map[12] of the hotspots and ArcView shapefile and metadata for the Biodiversity Hotspots[13] including details of the individual endangered fauna in each hotspot, which is available fromConservation International.[14]
Biodiversity hotspots. Original proposal in green, and added regions in blue.[15]
Most biodiversity exists within the tropics; likewise, most hotspots are tropical.[16] Of the 34 biodiversity hotspots, 15 are classified as old, climatically-buffered, infertile landscapes (OCBILs).[17] These areas have been historically isolated from interactions with other climate zones, but recent human interaction and encroachment have put these historically safe hotspots at risk. OCBILs have mainly been threatened by the relocation of indigenous groups and military actions, as the infertile ground has previously dissuaded human populations.[18] The conservation of OCBILs within biodiversity hotspots has started to garner attention because current theories believe these sites provide not only high levels of biodiversity, but they have relatively stable lineages and the potential for high levels of speciation in the future. Because these sites are relatively stable, they can be classified asrefugia.[19]
The high profile of the biodiversity hotspots approach has resulted in some criticism. Papers such as Kareiva & Marvier (2003)[22] have pointed out that biodiversity hotspots (and many other priority region sets) do not address the concept of cost,[23] and do not considerphylogenetic diversity.[24]
^Russell A. Mittermeier, Norman Myers and Cristina Goettsch Mittermeier,Hotspots: Earth's Biologically Richest and Most Endangered Terrestrial Ecoregions, Conservation International, 2000ISBN978-968-6397-58-1
