Characteristics and conservation priority of threatened plants in the Yangtze valley

One hundred and twenty-seven threatened species listed in the China Plant Red Data Book were found in the Yangtze valley. One-third of them belonged to four families with high economic value, including Pinaceae, Magnoliaceae, Lauraceae and Ranuculaceae. Of all the plants, 66.9% grew in forests and 71.7% were threatened with damage to habitats. The threatened plants in the studied region formed a geographical pattern with two large and six small distribution centers. The two large centers were in the high mountains in western Sichuan and northern Yunnan or around the Sichuan Basin. The six small centers were situated in fragmented montane forests in the eastern part of the Yangtze valley. To determine a plant's threat category, the number of populations less than or equal to10 was used as the basic criterion as accorded with the China Plant Red Data Book. The threatened plants in the valley could be divided into five ranks of priority for conservation. The plants in the first rank comprised eight species endemic to the valley, with only one population, which should be first preserved. It was concluded that human activity was the main factor threatening the survival of plants, and protecting forests had been the most effective approach in saving the threatened plants in the valley.