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Biodiversity hotspot

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A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is under threat from humans.

The concept of biodiversity hotspots was originated by Dr. Norman Myers in two articles in “The Environmentalist” (1988[1] & 1990[2]), revised after thorough analysis by Myers and others in “Hotspots: Earth’s Biologically Richest and Most Endangered Terrestrial Ecoregions” (1999). The hotspots idea was also promoted by Russell Mittermeier in the popular book “Hotspots revisited” (2004), although this has not been subjected to scientific peer-review like the other hotspots analysis.

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 0.5% or 1,500 species of vascular plants as endemics, and it has to have lost at least 70% of its primary vegetation[3]. Around the world, at least 25 areas qualify under this definition, with nine others possible candidates. These sites support nearly 60% of the world's plant, bird, mammal, reptile, and amphibian species, with a very high share of endemic species.

Hotspot conservation initiatives

Only a small percentage of the total land area within biodiversity hotspots is now protected. Several international organizations are working in many ways to conserve biodiversity hotspots.

  • Conservation International applies innovations in science, economics, policy and community participation to protect the Earth's richest regions of plant and animal diversity including: biodiversity hotspots, high-biodiversity wilderness areas and important marine regions. CI works in more than 40 countries on four continents, with headquarters near Washington, D.C..[5]
  • The World Wildlife Fund has derived a system called the “Global 200 Ecoregions”, the aim of which is to select priority Ecoregions for conservation within each of 14 terrestrial, 3 freshwater, and 4 marine habitat types. They are chosen for their species richness, endemism, taxonomic uniqueness, unusual ecological or evolutionary phenomena, and global rarity. All biodiversity hotspots contain at least one Global 200 Ecoregion.
  • Alliance for Zero Extinction is an initiative of a large number 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 a large number of Birdlife’ s Important Bird Areas.

These initiatives are all based on scientific criteria and quantitative thresholds.

The biodiversity hotspots by region

North and Central America

South America

Europe and Central Asia

Africa

Asia-Pacific

Critiques of Hotspots

The high profile of the biodiversity hotspots approach has resulted in considerable criticism. Papers such as Kareiva & Marvier (2003) [7] have argued that the biodiversity hotspots:

  • Do not adequately represent other forms of species richness (e.g. total species richness or threatened species richness).
  • Do not adequately represent taxa other than vascular plants (e.g. vertebrates, or fungi).
  • Do not protect smaller scale richness hotspots.
  • Do not make allowances for changing land use patterns. Hotspots represent regions that have experienced considerable habitat loss, but this does not mean they are experiencing ongoing habitat loss. On the other hand, regions that are relatively intact (e.g. the Amazon Basin) have experienced relatively little land loss, but are currently losing habitat at tremendous rates.
  • Do not protect ecosystem services
  • Do not consider phylogenetic diversity.

A recent series of papers has pointed out that biodiversity hotspots (and many other priority region sets) do not address the concept of cost [8]. The purpose of biodiversity hotspots is not simply to identify regions that are of high biodiversity value, but to prioritize conservation spending. The regions identified include regions in the developed world (e.g. the California Floristic Province), alongside regions in the developing world (e.g. Madagascar). The cost of land is likely to vary between these regions by an order of magnitude or more, but the biodiversity hotspots do not consider the conservation importance of this difference.

References

  1. ^ Myers, N. The Environmentalist 8 187-208 (1988)
  2. ^ Myers, N. The Environmentalist 10 243-256 (1990)
  3. ^ Myers, N. et al. Nature 403, 853–858 (2000)
  4. ^ The Critical Ecosystem Partnership FundOfficial website
  5. ^ About Conservation International, retrieved 10/1/2007CI's Mission
  6. ^ Conservation International (2007) BIODIVERSITY HOTSPOTS Resources
  7. ^ Kareiva, P. and M. Marvier (2003) Conserving Biodiversity Coldspots, American Scientist, 91, 344-351.
  8. ^ Possingham, H. and K. Wilson (2005) Turning up the heat on hotspots, Nature, 436, 919-920.
General references
  • Myers, N., R. A. Mittermeier, C. G. Mittermeier, G. A. B. da Fonseca, and J. Kent. 2000. Biodiversity hotspots for conservation priorities. Nature 403:853-858

Further reading

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