Natural Distribution and Ex Situ Conservation of Endemic Species Myricaria laxiflora in Water-level-fluctuation Zone within Three-Gorges Reservoir Area of Changjiang River

Myricaria laxiflora is a narrowly distributed species endemic to the water-level-fluctuation zone within the Three-Gorges Reservoir Area of Changjiang River. The construction of Three-Gorges Dam will raise the water level, which will completely submerge the wild populations of the species. This paper updated information of M. laxiflora natural distribution by a recent survey that extensively collected data in its geographic distribution, natural habitat and community structure of the species. The data showed that a total of 31 populations of approximate 90000 plants were grown in alluvial strips along the Changjiang River in 12 counties from Chongqing to Yichang. New distributions in 7 counties were found in this survey, and 18 more populations, 80000 more plants investigated than that of previous studies. The species was also found to have several unique characteristics such as, warm climate and moisture loving, opposite seasonal growing (growing in winter), numerous seeded, easily clonal propagation by cuttings. There are only few other species in its natural community of M. laxiflora, and the species number and structure in the community varies according to the water level fluctuation. The paper also reviewed current research progresses in ex situ conservation for rescuing the species and discussed ecological adaptation, evolutionary history, possible spreading mechanism and causes of the species endangerment. Suggestion for further conservation of the species was proposed.