New global map that charts plant diversity

By Kirtiman Awasthi
Published: Thursday 31 May 2007

-- now it will be easier to gauge the likely impact of climate change on the services plants provide human beings. Researchers at the University of California and the University of Bonn in Germany have produced a global map of estimated plant species' richness. The map, which accompanies a study published on April 3, 2007, in the Proceeding of National Academy of Sciences (Vol 104, No 14) highlights areas of particular concern for conservation.

"Plants provide important services to humans--ornaments, food, materials for drugs and alternative fuels--that increase in value with their richness," says Walter Jetz, assistant professor of biology at ucsd and one of the authors of the paper. Tropical countries are almost 10 to 100 times more in richness than most parts of the us or Europe.

The researchers found that richness in a region is based on its environmental conditions."Given that it is difficult to know the individual distribution of the world's 300,000-odd plant species, we investigated how well the richness of plants can be predicted from environmental conditions," Jetz said.

The researchers analysed about 40 indicators (such as daily temperature, number of dry/wet days, latitude, annual rainfall) in 1,032 geographic regions. These represented natural (mountain ranges, desert) and political units (countries, provinces, national parks).

The study concluded that evapotranspiration, number of wet days per year, topographical characteristics and diversity of habitat are the major factors responsible for species richness. For example, the South African Cape region contains more than twice as many species as expected by the global environmental model.

"The map highlights areas of particular concern for conservation and helps pinpoint areas that deserve further attention for the discovery of plants. It also helps assess impact of climate change," Jetz said.

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