Collapse_ How Societies Choose to Fail or Succeed - Jared Diamond [227]
The other two most serious forms of habitat destruction in China besides deforestation are destruction or degradation of grasslands and wetlands. China is second only to Australia in the extent of its natural grasslands, which cover 40% of its area, mainly in the drier north. However, because of China’s large population, that translates into a per-capita grassland area less than half of the world average. China’s grasslands have been subject to severe damage by overgrazing, climate change, and mining and other types of development, so that 90% of China’s grasslands are now considered degraded. Grass production per hectare has decreased by about 40% since the 1950s, and weeds and poisonous grass species have spread at the expense of high-quality grass species. All that degradation of grassland has implications extending beyond the mere usefulness to China of grassland for food production, because China’s grasslands of the Tibetan Plateau (the world’s largest high-altitude plateau) are the headwaters for major rivers of India, Pakistan, Bangladesh, Thailand, Laos, Cambodia, and Vietnam as well as of China. For example, grassland degradation has increased the frequency and severity of floods on China’s Yellow and Yangtze Rivers, and has also increased the frequency and severity of dust storms in eastern China (notably in Beijing, as seen by television viewers around the world).
Wetlands have been decreasing in area, their water level has been fluctuating greatly, their capacity to mitigate floods and to store water has decreased, and wetland species have become endangered or extinct. For example, 60% of the swamps in the Sanjian Plain in the northeast, the area with China’s largest freshwater swamps, have already been converted to farmland, and at the present ongoing rate of drainage the 8,000 square miles remaining of those swamps will disappear within 20 years.
Other biodiversity losses with big economic consequences include the severe degradation of both freshwater and coastal marine fisheries by overfishing and pollution, because fish consumption is rising with growing affluence. Per-capita consumption increased nearly five-fold in the past 25 years, and to that domestic consumption must be added China’s growing exports of fish, molluscs, and other aquatic species. As a result, the white sturgeon has been pushed to the brink of extinction, the formerly robust Bohai prawn harvest declined 90%, formerly abundant fish species like the yellow croaker and hairtail must now be imported, the annual take of wild fish in the Yangtze River has declined 75%, and that river had to be closed to fishing for the first time ever in 2003. More generally, China’s biodiversity is very high, with over 10% of the world’s plant and terrestrial vertebrate species. However, about one-fifth of China’s native species (including its best-known one, the Giant Panda) are now endangered, and many other distinctive rare ones (such as Chinese Alligators and ginkgos) are already at risk of extinction.
The flip side of these declines in native species has been a rise in invasive species. China has had a long history of intentionally introducing species considered beneficial. Now, with the recent 60-fold increase in international trade, those intentional introductions are being joined by accidental introductions of many species that no one would consider beneficial. For example, in Shanghai Harbor alone between 1986 and 1990, examination of imported materials carried by 349 ships from 30 countries revealed as contaminants almost 200 species of foreign weeds. Some