Low genetic diversity in marginal populations of Bletilla striata (Orchidaceae) in southern Korea: Insights into population history and implications for conservation

The warm-temperate vegetation of Korea, currently limited to southern coastal areas, shifted southward during the Last Glacial Maximum towards glacial refugia putatively located in southern Japan and/or southern China. We hypothesized two scenarios of postglacial re-colonization of warm-temperate species: (i) that extant Korean populations originated from a single source or (ii) that they are derived from multiple source populations. To test which of these scenarios is more likely, we investigated the patterns of genetic diversity in 16 populations of the warm-temperate terrestrial orchid Bletilla striata, employing 20 allozyme loci. Levels of genetic variation in B. striata were substantially lower than those reported in most other terrestrial orchids. However, the degree of genetic differentiation among populations was moderate. These results suggest a pattern of post-glacial re-colonization fitting the first scenario. Both in situ and ex situ conservation strategies are suggested to preserve the genetic variation of B. striata in Korea. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.