Genetic perspective on forest management of Scots pine (Pinus sylvestris L.) in protected areas

Silviculture in the past involved the movement of seeds across large geographical areas. Such planted forests of unknown origin occur within the borders of some recently established national parks and other protected areas. Identification of such populations of anthropogenic origin is important for the maintenance of stands of primeval nature. In the presented study, we analysed natural and putatively planted (seminatural) Scots pine populations (total of 207 trees) derived from Roztocze National Park (Roztoczański Park Narodowy - RPN) which was established in 1974 to protect the unique natural forests and landscape of the geographical region Roztocze in south-eastern Poland. The genetic profiles of pines in RPN were analysed using polymorphism of mitochondrial DNA (mtDNA) regions and a set of nuclear loci (nDNA). We used the data to investigate the genetic relationships between the analyzed stands, infer fine-scale population structure, and find any trace of foreign origin of some populations. The genetic diversity of pines in the RPN was compared with each other and with the set of oldest lowland and mountain populations of the species in Poland (436 trees). The most common haplotypes in mtDNA were present in all populations, providing weak evidence of a significant spatial structure of pines studied in RPN. The vast majority of genetic variation (∼99 %) in nuclear markers was present in every population and a similar level of genetic variation within the population was observed in the RPN populations and most reference stands. Population structure, phylogeographic and molecular variance analysis indicated some divergence in three RPN populations (2 planted and one natural) driven by the presence of individuals genetically similar to Scots pine from the Tatra and Pieniny mountains. Other populations of the RPN were genetically very similar to each other and lowland Scots pine stands, including the oldest populations of the species and stands from other geographical locations. Demographic analysis showed that the populations in the analysed distribution of Scots pine have a common origin and their divergence started relatively recently as a result of population isolation, differentiation due to genetic drift, and the likely influence of natural selection. If the seminatural populations in the RPN are of anthropogenic origin, they were planted from seeds collected locally. The results indicate that the genetic variation of Scots pine in Roztocze National Park is maintained in natural populations and active management of planted stands will not affect the gene pool of the species in this area. This research highlight the importance of genetic studies of keystone species at protected areas to advance conservation and management of such ecosystems.