National Geographic : 2002 Jul
Spilled along the Pacific's edge, the 7,000 islands of the Philippines rose from the collision of tectonic plates and vol canic activity. Plants and animals evolved in iso lation, migrating to other islands mainly during Ice Age low water. Coral reefs of the Calamian islands in Palawan (left) sustain fishermen in out rigger bancas. (h S. Sa Old-growth forest SUBTERRATEA 1960 NATIONAL m 1992 SReef 0mi 100 0km 100 IMAGEBY ROBERTSTACEY. WORLDSATINTERNATIONALINC. " SOURCES: CONSERVATIONINTERNATIONAL; FORESTCOVERBYHEANEYAND REGALADO(1998), MODIFIEDFROM DEVELOPMENTALTERNATIVESINC. f4® (1992) ANDHUKE11963);REEFDATA BY WORLDRESOURCESINSTITUTE NATIONALGEOGRAPHICMAPS volcanoes. The islands emerged from the grind of tectonic plates in the Pacific some 50 million years ago. Their shorelines fell and rose with the ice ages, and they were sometimes linked to one another by land bridges. But the Asian mainland remained hundreds of miles away, except for a few stepping-stone islands. Migra tion back and forth was impossible for most creatures, so each Philippine island evolved in virtual isolation, with its own unique species. Forests once carpeted 96 percent of the archipelago's landmass-mangrove swamp, lowland rain forest, montane forest in the foot hills, and mossy forest on the summits. That cover has now dwindled to less than 18 per cent, with only 7 percent of the original uncut forest left. Commercial and small-time logging for Philippine mahogany, slash-and-burn farming, and mining have nearly ruined some islands, leaving them vulnerable to severe ero sion, floods, and droughts. The thin layer of topsoil has simply run into the ocean, and what remains is virtually bereft of nutrients, useless even for agriculture. This runoff has led to spoiled waters as well. River silt has killed coral reefs by denying them sunlight. Many poor fishermen add to reef destruction by using cyanide to stun and cap ture live fish for the aquarium trade. Others dynamite the reefs to blast food fish to the surface. Miles of reefs have been bleached by recent El Nifo hot spells. The Visayas, the smaller islands wedged between Luzon in the north and Mindanao on the south, are at seri ous risk of economic collapse. "Look at Cebu, an island that's 99 percent denuded," said Danilo "Danny" Balete, a biolo gist with Laksambuhay Conservation, an envi ronmental NGO in Manila. "It's mainly forest over limestone. Now only a tiny layer of soil is left clinging to the deforested areas. You can plant some corn if you're lucky. Once you've THE PHILIPPINES Btan Is.