1 Tahrcountry Musings: World’s tropical forests – A look in to what future holds

Saturday, January 17, 2009

World’s tropical forests – A look in to what future holds

The recent Smithsonian’s Symposium: “Will the rainforests survive? New Threats and Realities in the Tropical Extinction Crisis” had some interesting observations. It brought together the world's foremost authorities on different aspects of rainforest science.
One of the main arguments put forward was that the extinction crisis might not be as bad as predicted due to the significance of secondary forests and other degraded landscapes, which may allow the preservation of certain species. Robin Chazdon, a professor at the University of Conneticut who has studied secondary forests for twenty-five years, stated that secondary forests and other non-primary growth landscapes has great relevance for biodiversity conservation. According to him these are the areas that needs focused attention in order to conserve most of our biodiversity. A study in Veracruzm Mexico came up with the finding that bird biodiversity was actually greater in shade grown coffee farms than in the forest. In the Western Ghats of India, where cultivation has been practiced for 2,000 years, arecanut agriculture retains 90 percent of the bird biodiversity of the forest. In the largely degraded and devastated Atlantic Forest of Brazil chocolate grown under the canopy provides homes for 70 percent of many species, including birds, bats, butterflies, mammals, ferns, lizards and frogs. In Costa Rica, scientists discovered that a forest less than twenty years old had 90 percent of forest tree species either already growing or as seedlings. On the other hand soybean fields have been found to be devoid of biodiversity. Biodiversity is abysmally poor in palm oil plantations. Palm oil plantations have been shown to retain only 15 percent of species from the lost forest.
Entomologist Nigel Stork from the University of Melbourne argued that the scientists who predicted extinction rates of 50-75 percent did not take into account that certain groups of species, such as birds and mammals, are more prone to extinction than other groups like insects. Large body size, small restricted range, low number of young, top of the food chain, high specificity to another organism, and low physiological adaptation make a species more vulnerable to extinction.
One place where the scientists at the Symposium largely agreed was the threat posed by climate change to the tropics and the inability to know how it would affect biodiversity in the region. All the participants believe that this is a much greater threat to biodiversity in the tropics than habitat destruction. Tropical species are much more sensitive to small increases in temperature than temperate species. Tropical species would have to travel much greater distances than temperate species to find habitat within their normal range of temperatures.
According to Gregory Asner of the Carnegie Institution, deforestation is still the dominant pattern in tropical forests worldwide. To be precise it is on the rise. With the globalization of trade, deforestation mainly occurs for industrialized agriculture, such as soy and palm oil, and for logging to produce wood products meant for export to the West. Consumption by wealthy nations, and not local needs, is largely driving contemporary deforestation.
At the end of the symposium all the speakers foresaw mass extinction in the future of the tropics, unless drastic ameliorative actions are taken on a war footing. While the extinction may not reach 50-75 percent, since insects dominate the world, it would certainly have a devastating effect on the world’s vertebrates. Robin Chazdon argued that in order to ensure enough habitats, secondary forests and agroforestry should be supported. A conservation action plan for such areas is the need of the hour.

No comments: