| Three years http://egotastic.in.net/ egotasticallstars.com The filling of the Chiew Larn Reservoir in southern Thailand in 1986 and 1987 created more than 100 islands and presented a rare opportunity to study the effects of sudden isolation on small-mammal communities. In the early 1990s, a team led by population geneticist David Woodruff of the University of California, San Diego, set traps to survey small mammals on 12 of the islands, ranging in size from 0.3 to 56.3 hectares. They found that after 5 to 7 years of isolation, the three biggest islands were still home to seven to 12 species of mice, rats, squirrels, and shrews. The range of species was similar to that found in a large, undisturbed forest on the nearby mainland. On the small islands, however, the researchers found just one to three species, indicating a rapid decline in diversity, presumably because the islands were too small to sustain animal communities. |
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