Sunday, April 11, 2010
Siberian Crane, CR ( critically endangered)
CR, (critically endangered)
mixed media, hand sewn and beaded painted leather figure seated on hand made wooden chair
photograph by Bruce Mathews
CR, (critically endangered)
Adult Siberian cranes stand five feet tall and weigh only thirteen pounds. Females generally lay two goose-sized olive green eggs which are incubated for twenty-nine days. Rarely do both chicks live. Siberian cranes are omnivores. Whilst living on the breeding grounds, they will hunt rodents,fish, insects, and gather cranberries. On migration and whilst living on wintering grounds these cranes dig up nutrient rich roots and tubers from the wetlands. The oldest living documented Siberian crane lived to be eighty-three years old.
Nine of the fifteen species of cranes worldwide are threatened with extinction. The Siberian crane with a rapidly declining population of less than three thousand is listed as critically endangered. Historically there were three populations of Siberian cranes.
The western population's breeding ground is in Russia just south of the Ob River and east of the Ural Mountains. They migrate southward to a single site along the south coast of the Caspian Sea in Iran. The crane's primary threat here comes from human hunters.
There is little doubt that the central population has been extirpated. This population once nested in western Siberia and migrated south to India, spending a resting period in Afghanistan. The last documented sighting of a Siberian crane in India during the winter months was in 2002.
The eastern population which makes up 95% of the entire Siberian crane global population locates its nesting grounds on the lowland tundra of northeastern Siberia near the Arctic Circle in wetlands, bogs, and marshes. These cranes winter along the lower Yangtze River (Chang Jing) in China. It is here, in China, where the species is threatened with losing its critical wetland habitat.
This wetland habitat is Poyang Hu lakes, a maze of small lakes and marshes filled with shallow water, wet meadows, and broad mudflats. During summer floods, this area grows into a single lake which shrinks every year becoming the perfect wetland habitat for cranes and numerous other migratory waterfowl. This critical habitat is in the lower Yangtze River basin in southeastern China.
Siberian cranes are threatened in these wetlands by commercial hunters and by farmers who are draining the pools of water, gaining new cropland. A growing human population also threatens this habitat. But by far the most imposing imminent threat to the very survival of this population is the manmade Three Gorges Dam. This hydroelectric dam spans the Yangtze River, upriver from the Poyang ecosystem. Below this dam, plans are to deepen and re-channel the lower river to improve transportation, agriculture, and industry. These changes will disrupt the seasonal flow of the river and change water levels in the lowlands. This dam also threatens other endangered species such as the Yangtze dolphins, Chinese sturgeons, Chinese tigers, Chinese alligators, and giant pandas.