Threats to biodiversity rise in the world's Mediterranean-clima...( In the first systematic analysis of ...)

In the first systematic analysis of threats to the biodiversity of the world's mediterranean-climate regions, scientists at The Nature Conservancy and UC Davis report that these conservation hotspots are facing significant and increasing pressure. The study, which appears in this week's edition of the journal Diversity and Distributions, is part of a global conservation assessment of the rare mediterranean biome.

"Throughout human history, the mild climates of mediterranean regions have fostered growth of major urban centers, vast agricultural zones and dense human populations all in the midst of some of the rarest biodiversity on Earth", says Dr. Rebecca Shaw, a scientist with The Nature Conservancy's California program and the leader of the global assessment.

Mediterranean climates characterized by warm, dry summers and cool, wet winters are extremely rare, found on only 2% of the Earth's land surface: portions of California/Baja California, South Africa, Australia, Chile, and the Mediterranean Basin. Increasing the pace and scale of conservation in mediterranean regions is critically important to biodiversity protection, because these regions contain 20% of the world's plant species.

"If we are to reduce rates of biodiversity loss, then understanding patterns and trends in threats is of paramount importance," says lead author Dr. Emma Underwood, a research scientist at the Information Center for the Environment at the University of California, Davis.

To this end, scientists from The Nature Conservancy and U. C. Davis analyzed changes in land use and population density in the world's five mediterranean-climate regions.

Overall, population density and urban areas increased in these regions by 13 percent from 1990 to 2000, while agricultural areas spread by 1 percent. Population grew by over 34 million people from 1990 to 2000, twice the population of Chile. Urban areas expanded by 2,110 square mile
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