Genetic Diversity and Spatial Genetic Structure in Isolated Scots Pine (Pinus sylvestris L.) Populations Native to Eastern and Southern Carpathians

Nicolae Șofletea,Elena Ciocîrlan,Alexandru Lucian Curtu,Georgeta Mihai

doi:10.3390/f11101047

Abstract

Small, isolated populations are more vulnerable to natural disturbances and loss of genetic diversity. Scots pine, an abundant tree species in the boreal forest of Eurasia, has a scattered natural distribution across Eastern and Southern Carpathian Mountains, where only a few relict populations still exist. We estimated genetic diversity and spatial genetic structure in Scots pine on the basis of microsatellite nuclear markers (nSSR) data. We found a relatively high level of genetic diversity (He = 0.697) within populations and no evidence of recent bottlenecks. Genetic diversity was lower in peat bog populations, as compared to populations that grow on rocky slopes or acidic soils and nutrient-poor sites. Population genetic structure was weak, and genetic discontinuities among populations were detected. Spatial genetic structure (SGS) was observed in nearly all Scots pine populations. The strength of SGS, quantified by Sp statistics, varied greatly among populations, ranging from 0.0011 to 0.0207, with an average of 0.01. Our study highlights that Eastern and Southern Carpathian populations still possess high within-population diversity in spite of the recent fragmentation and reduction of the Scots pine natural distribution range. We discuss the importance of spatial patterns of genetic diversity for developing strategies of conservation and sustainable use of Scots pine genetic resources in the Carpathian region.

Highlights

Relict forest tree populations, i.e., populations that are presently confined to a small territory, but whose original distribution range was much larger in the past, may contribute substantially to the genetic diversity of a particular species [1]
Isolated populations, which are located at the margins of species distribution range, may harbor rare, unique genetic variants that might be of importance for species survival under changing environmental conditions [2,3]
Spatial genetic structure (SGS) within natural tree populations derives from a series of interacting genetic and demographic processes, which may be difficult to disentangle [6,7,8]

Summary

Introduction

Relict forest tree populations, i.e., populations that are presently confined to a small territory, but whose original distribution range was much larger in the past, may contribute substantially to the genetic diversity of a particular species [1]. Isolated populations, which are located at the margins of species distribution range, may harbor rare, unique genetic variants that might be of importance for species survival under changing environmental conditions [2,3]. The genetic diversity of geographically marginal populations, which are typically small and island-like, may be reduced due to higher genetic drift, increased inbreeding, limited or lack of gene flow from other populations, and natural selection after long periods of time of survival in new ecological settings [4,5]. A stronger SGS is expected in gravity-dispersed than in wind-dispersed tree species [9]

Methods

Results

Discussion

Conclusion