Spatial genetic structure of an endangered orchid Cypripedium calceolus (Orchidaceae) at a regional scale: limited gene flow in a fragmented landscape

Abstract

Plant species that are capable of propagating clonally are expected to be less vulnerable to habitat fragmentation due to their long life span. Cypripedium calceolus L. is a rare, clonal, long-lived orchid species. It has suffered marked decline because of habitat loss and fragmentation and over-collection, yet an IUCN report on this species does not regard fragmentation as a major threat to the species. We applied 13 nuclear microsatellites and cpDNA sequences to identify the patterns of population structure, genetic diversity and connectivity of six remnant local populations of C. calceolus in highly fragmented Gdańsk Pomerania region (N Poland). Despite severe (80%) loss of localities in the studied area we found that the local populations retain high levels of clonal (R 0.86-1) and genetic diversity (H e = 0.572). However, their differentiation is relatively high (F ST = 0.132 for nuclear SSR and F ST = 0.363 for cpDNA) despite close geographic proximity (0.6-57 km). Bayesian clustering classified populations according to their geographic origin with little admixture. Low genetic connectivity between the remnant populations shows that the current gene flow is too low to serve as a cohesive force in a fragmented habitat, which may impede a quick response to environmental change. The species' ability to retain ancestral variation may help withstand fragmentation, but in the light of observed extirpation rate it should be rather considered as a factor that only delays local populations' extinction. This leads to the conclusion that habitat loss and fragmentation should be regarded as a real threat to stability of C. calcelolus populations.

Conserving on the edge: genetic variation and structure in northern populations of the endangered plant Dracocephalum ruyschiana L. (Lamiaceae)

“…Compared with other threatened plants (e.g. Tero et al 2005;Dostálek et al 2010; but see Minasiewicz et al 2018), the genetic variation in the studied D. ruyschiana sites seem to be moderate. As different genetic markers have been applied in these studies, the interpretation of genetic variation should be treated cautiously.…”

“…4) studied so far. However, spatial genetic structuring may also be present even at a local scale (Minasiewicz et al 2018;Tero et al 2005) and regions such as the valleys stretching north-westwards, represented by few sites and/or individuals, should be further explored for undetected genetic variation in D. ruyschiana.…”

Comparative Plastid Genomics of Neotropical Bulbophyllum (Orchidaceae; Epidendroideae)

“…Owing to their high mutation rates (Gemayel et al, 2010), SSRs have been extensively used in populations genetic and phylogenetic studies (Kartzinel et al, 2013;Minasiewicz et al, 2018). Here, a total of 54 polymorphic SSRs were identified.…”

The Impact of Human Pressure and Climate Change on the Habitat Availability and Protection of Cypripedium (Orchidaceae) in Northeast China

“…In this study, we investigated the impact of human activities on the environment and climate change on the distribution of three Cypripedium species in northeast China. In recent decades, overcollection, habitat loss and fragmentation have led to substantial decreases in the distribution and abundance of lady’s slipper orchids in China and elsewhere in the world [ 47 , 48 , 49 ]. Maxent and ArcGIS were used to assess the importance of multiple environmental variables (including bioclimatic and topographical variables, soil type, vegetation type and human activities) determining the distribution of lady’s slipper orchids in northeast China.…”