POPULATION GENETIC-STRUCTURE AND CONSERVATION OF AN ENDANGERED CONIFER, CATHAYA-ARGYROPHYLLA (PINACEAE)

Cathaya argyrophylla is an endangered conifer restricted to subtropica l mountains of China, with total number of individuals less than 4,000 . To assess levels and patterns of genetic diversity of C. argyrophyll a, eight populations representing four widely separated regions were a nalyzed for allozyme variation, using 13 enzymes. In comparison with o ther coniferous species, C. argyrophylla possesses a low amount of var iation, particularly at the population level (A = 1.38; P = 30.4; H-e = 0.102). By contrast, the level of population differentiation is much higher (F-ST = 0.441) compared to other conifers, and significant dif ferentiation occurs both between regions and between populations withi n a region. Climate, geologic, and fossil data suggest that historical factors are mainly responsible for the unique population genetic stru cture in C. argyrophylla. These factors include severe bottleneck and subsequent genetic drift during Quaternary glaciations and habitat det erioration and fragmentation in postglaciation. In addition, reduced g ene flow and relatively high rates of inbreeding may be factors that l ead to low population variability and marked genetic differentiation a mong populations. Implications for the development of conservation str ategies for this endangered species are discussed on the basis of thes e findings.