Hotspots and threatened habitats

Posted: 6 May 2008

Biodiversity is highest in the tropics, but this is where human populations tend to be growing fastest, exacerbating the conflict between human populations and biodiversity.

  • More than 1.1 billion people live in the 25 biodiversity hotspots identified by Conservation International. In 19 of these areas population is growing faster than the world average (see chart).

  • Some 75 million people live in the three largest tropical wilderness areas: the Upper Amazon, the Congo River Basin, and the New Guinea-Melanesia complex of islands. Population in these areas is growing at 3.1 per cent per year, more than double the world average.

  • Several of the hotspots in developed countries are also places where human population growth is more rapid than national averages, as people migrate to warmer or more attractive areas. This applies, for example, to New Zealand, Western Australia, Florida, Hawaii and California.

  • The California Floristic Province hosts 28,000 species of insect, of which 9,000 are endemic, 340 birds, 157 mammals, 69 reptiles and 46 amphibians (of which over half are endemic). It also has over 2,000 endemic species of plant. Yet human population has grown here from 1 million in 1850 to more than 35 million in 2002, and it is the fastest growing state in the USA. Only 1 per cent of California's original grassland remains, along with only 15 per cent of the original redwood forests and 6 per cent of the interior wetlands. In 2004, 33 of California's terrestrial vertebrate species were listed as threatened.

  • There is a close link between the level of pollution in rivers and human population density in the watershed: the higher the density, the higher the levels of nitrates in the water.

See Hotspots Map

Sources:Conservation International: Biodiversity HotspotsPaul Harrison, The Third Revolution, Penguin Books, London, 1993.Richard Cincotta and Robert Engelman, Nature's Place, Population Action International, Washington, 2000.