Genetic structure in Pinus cembra from the Carpathian Mountains inferred from nuclear and chloroplast microsatellites confirms post-glacial range contraction and identifies introduced individuals

Abstract

Genetic differentiation of scattered populations at neutral loci is characterized by genetic drift counteracted by the remaining gene flow. Populations of Pinus cembra in the Carpathian Mountains are isolated and restricted to island-like stands at high-elevation mountain ranges. In contrast, paleobotanical data suggest an extended early Holocene distribution of P. cembra in the Carpathians and its surrounding areas, which has contracted to the currently disjunct occurrences. We analyzed the genetic variation of 11 Carpathian populations of P. cembra at chloroplast and, in part newly developed, nuclear microsatellites. Both marker types revealed low levels of genetic differentiation and a lack of isolation by distance, reflecting the post-glacial retraction of the species to its current distribution. Stronger effects of genetic drift were implied by the higher genetic differentiation found for haploid chloroplast than for diploid nuclear markers. Moreover, we found no association between the values of population genetic differentiation for the two marker types. Several populations indicated recent genetic bottlenecks and inbreeding as a consequence of decline in population sizes. Moreover, we found individuals in two populations from the Rodnei Mountains that strikingly differed in assignment probabilities from the remaining specimens, suggesting that they had been introduced from a provenance outside the studied populations. Comparison with Eastern Alpine P. cembra and individuals of the closely related Pinus sibirica suggests that these individuals presumably are P. sibirica. Our study highlights the importance of the maintenance of sufficiently large local population sizes for conservation due to low connectivity between local occurrences.

Genetic evidence of human mediated, historical seed transfer from the Tyrolean Alps to the Romanian Carpathians in Larix decidua (Mill.) forests

“…Of particular interest is that in R3 (which is obviously from north-eastern Tyrolian origin), no first-generation migrants from autochthonous Romanian populations were detected. Our results of nuclear microsatellite diversity are similar to other studies on L. decidua (King et al 2013;Pluess 2011;Wagner et al 2012) and to other conifer species with similar habitat demands in boreal or temperate forest associations such as P. abies (King et al 2013;Tollefsrud et al 2009), P. cembra (Dzialuk et al 2014;Lendvay et al 2014), or Pinus sylvestris (Pazouki et al 2016). In general, high levels of diversity within populations in long-lived, outcrossing, and late successional coniferous taxa were obtained.…”

Biogeography of the Carpathians: evolutionary and spatial facets of biodiversity

“…The evolutionary importance of the south‐western edge of the Carpathians was recently supported by the phylogeographical structure of the montane plant Onobrychis transylvanica (Fabaceae; Băcilă et al ., ). The same area also hosted a divergent population of Pinus cembra (Pinaceae), probably derived from a spatially restricted relict lineage in an otherwise homogeneous Carpathian gene pool (Lendvay et al ., ). It also emerged as a likely centre of relict diversity in a study on a complex of poorly dispersing freshwater amphipods (Copilaş‐Ciocianu & Petrusek, ).…”

Development of nuclear microsatellite loci for Pinus albicaulis Engelm. (Pinaceae), a conifer of conservation concern

“…albicaulis , including 14 loci from P . cembra L. (Swiss stone pine) [ 64 , 65 ], three loci from P . parviflora (Japanese white pine) [ 66 ], 13 loci from P .…”