Extremely Low Levels of Allozyme Variation in Southern Korean Populations of the Two Rare and Endangered Lithophytic or Epiphytic Bulbophyllum Drymoglossum and Sarcanthus Scolopendrifolius (Orchidaceae): Implications for Conservation

Abstract

Allozyme variation was investigated in two local populations of Bulbophyllum drymoglossum and three populations Sarcanthus scolopendrifolius, two rare and endangered lithophytes and epiphytes from South Korea. Genetic diversity was extremely low within populations (mean H e = 0.011 for B. drymoglossum; 0.002 for S. scolopendrifolius). Among the putative screened 21 loci, we found only one polymorphic locus for each species. Only one polymorphic locus, detected just one population of each species, revealed significantly high degree of population differentiation between and among populations (F ST = 0.253 for B. drymoglossum and F ST = 0.899 for S. scolopendrifolius). These results suggest that genetic drift (consequence of a very small effective population size), coupled with a limited gene flow would play a major role in shaping population genetics of these species in South Korea. The current status of both species (small population sizes, spatially isolated populations, and highly localized habitats) in addition to the extremely low levels of genetic diversity and reckless collection of endangered orchids by plant sellers, significantly threaten the long-term survival of these species in Korea. Conservation of the two species requires both in situ strategies, by introducing of genets to increase effective population sizes by minimizing adverse effects (e.g., outbreeding depression and genetic swamping by non-native genotypes), and ex situ strategies, such as collection of genets from clonal ramets.

Extremely low levels of genetic diversity in the terrestrial orchid Epipactis thunbergii (Orchidaceae) in South Korea: implications for conservation

“…According to the literature, a total lack of genetic variation, or extremely low levels, has often been documented in terrestrial orchids (Scacchi, De Angelis & Corbo, 1991; Bornbusch, Swender & Hoogerwert, 1994; Case, 1994; Sun, 1997; Ramsey & Stewart, 1998; Chung et al ., 2007; Chung, Park & Chung, 2007). In addition, levels of genetic diversity in an orchid species vary substantially depending on location (Bornbusch et al ., 1994; Case et al ., 1998; Wong & Sun, 1999; Gustafsson, 2000).…”

Population history of the terrestrial orchidCremastra appendiculatavar.variabilisfrom Korea, inferred from levels and distribution of genetic diversity

“…Source references: 1, Chung et al . (); 2, Chung, Park & Chung (); 3, Chung et al . (); 4, this study; 5, Chung & Chung (); 6, Chung et al .…”

“…and Sarcanthus scolopendrifolius Makino (Table ). These lithophytic species are extremely rare in southern Korea and are characterized by small, highly isolated populations (Chung, Park & Chung, ). This genetic pattern would fit better with a scenario of migration from a single glacial refugium, although low rates of recurrent gene flow among the highly isolated Korean populations could be an alternative or complementary explanation.…”

“…The few available pollen records suggest that the warmtemperate and subtropical vegetation, in contrast to temperate and boreal vegetation adapted to colder habitats, was probably absent from the Korean Pen-insula during the Last Glacial Maximum (LGM, c. 21 000 years ago) (e.g. Choi, 1998;Chung, Lim & Yoon, 2006;Chung, 2007;Chung, Lim & Lee, 2010;Yi & Kim, 2010). The warmer and more humid conditions of the Holocene allowed the return of the warmtemperate and subtropical vegetation, the first appearance of which on the peninsula has been dated at c. 8500 years ago (Chung, 2011), and somewhat earlier on Jeju Island (Fig.…”

“…The warmer and more humid conditions of the Holocene allowed the return of the warmtemperate and subtropical vegetation, the first appearance of which on the peninsula has been dated at c. 8500 years ago (Chung, 2011), and somewhat earlier on Jeju Island (Fig. 1; c. 12 000-10 000 years BP; Chung, 2007). Thus, the most plausible scenario for the dynamics of the warm-temperate and subtropical vegetation during the last glacial/interglacial cycle of the Quaternary is survival in southern glacial refugia followed by post-glacial migrations into the Korean Peninsula, rather than its persistence in domestic (i.e.…”