CONSERVATION in many parts of the tropics relies on preserving fragments of forest left over after farmers have cleared the rest. But such efforts may be wasted on areas of 100 hectares or less, which new research suggests are too small to remain as self-regenerating ecosystems.
Julieta Benitez-Malvido of the National University of Mexico in Morelia studied 11 fragments of forest ranging in size from 1 to 100 hectares near Manaus, Brazil. She found that the density of shade-tolerant seedlingswhich represent the majority of treesdecreases dramatically towards the forest edge, and is up to 40 per cent less in the corners of a fragment than in the centre. She concludes that below a certain size, rainforest segments cannot contain enough seedlings to fully regenerate the plant species within them (
"When I started the project, I thought seedling density would be higher closer to forest ...
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