A preliminary study on conservation genetics of an endangered orchid (Paphiopedilum micranthum) from southwestern China.

Knowledge about genetic diversity and population genetic structure is a good baseline for formulating effective conservation plans, and can often provide novel, conservation-relevant insights (Avise, 1996; Geburek, 1997; Hamrick and Godt, 1996). An effective conservation strategy for a species can be made only after detailed population genetic information becomes available (Hamrick and Godt, 1996). Nevertheless, studies on population genetics of orchid species are relatively limited given that Orchidaceae is one of the largest families of flowering plants (Ackerman and Ward, 1999; Ehler and Pedersen, 2000; Wong and Sun, 1999). Among the vast variety of orchid species, the genus Paphiopedilum holds a special place in the minds of orchid growers for their exotic, large flowers on small plants (Cribb, 1998). Because of their spectacular flowers and the technical difficulties associated with their ex situ cultivation and propagation, many Paphiopedilum species are faced with increasing collection pressure. In addition, decades of agriculture, silviculture, grazing, and urbanization have caused habitat destruction and degradation, which has significantly decreased both the extent and density of their populations (Cribb, 1998). These threats have brought them to the edge of extinction in the wild (Cribb, 1998; Tsi et al., 1999). Paphiopedilum micranthum is one of the most northerly distributed species in the genus Paphiopedilum and is restricted to the karst limestone hills of southwestern China, including southeastern Yunnan, northern and western Guangxi, and southwestern Guizhou (Fig. 1) (Chen and Tsi, 1998; Lang et al., 1999). Despite its