Fragmentation-related patterns of genetic differentiation in pedunculate oak (<i>Quercus robur</i>) at two hierarchical scales

Abstract

Highlights• While long-lived, widespread tree species should be resistant to genetic impoverishment, we detected high differentiation among populations and pronounced genetic structure within populations of Quercus robur in Finland.• These patterns seem indicative of population processes active at range margins, and of disequilibrium following historic habitat change. • Preservation of remaining genetic variation is thus important in the conservation of Q. robur. AbstractPopulations at species' range margins are expected to show lower genetic diversity than populations at the core of the range. Yet, long-lived, widespread tree species are expected to be resistant to genetic impoverishment, thus showing comparatively high genetic diversity within populations and low differentiation among populations. Here, we study the distribution of genetic variation in the pedunculate oak (Quercus robur L.) at its range margin in Finland at two hierarchical scales using 15 microsatellite loci. At a regional scale, we compared variation within versus among three oak populations. At a landscape scale, we examined genetic structuring within one of these populations, growing on an island of ca 5 km 2 . As expected, we found the majority of genetic variation in Q. robur to occur within populations. Nonetheless, differentiation among populations was markedly high (F ST = 0.12) compared with values reported for populations of Q. robur closer to the core of its range. At the landscape level, some spatial and temporal sub-structuring was observed, likely explained by the history of land-use on the island. Overall, Q. robur fulfils the expectation of the central-marginal hypothesis of high differentiation among marginal populations, but the notable population differentiation has most likely been influenced also by the long, ongoing fragmentation of populations. Finnish oak populations may still be adjusting to the drastic habitat changes of the past centuries. Preservation of genetic variation within the remaining stands is thus an important factor in the conservation of Q. robur at its range margin.

Genetic diversity and differentiation among populations of the pedunculate oak (Quercus robur) at the eastern margin of its range based on a new set of 95 SNP loci

“…The breaks between pedunculate oak generations in Russia are 60-80 years. It is possible that the relatively small and fragmented populations in this study are not yet in a stage of serious decreasing genetic diversity due to genetic drift (Pohjanmies et al 2016). Earlier it was noted that genetically effective long-distance pollen flow can be a factor in maintaining relatively similar genetic diversity in these populations (Buschbom et al 2011).…”

Climate and host genotype jointly shape tree phenology, disease levels and insect attacks

“…We have previously used 15 nuclear microsatellite loci to characterize genetic variation in the study landscape, including the five mother trees included in the current study. These studies revealed substantial genetic variation within the study landscape, with support for two genetic clusters (Pohjanmies et al 2015(Pohjanmies et al , 2016. While the five genotypes are selected from, and reflective of this landscape scale, we do note that the number of genotypes selected are too few to thoroughly represent the genetic variation at the landscape scale.…”

Genetic diversity in oak populations under intensive management for fuelwood in the Sierra de Zongolica, Mexico

“…Quercus species with authors Q. ilex (Michaud et al, 1995) Q. chrysolepis (Montalvo et al, 1997) Q. petraea(1) (Streiff et al, 1998) Q. robur(1) (Streiff et al, 1998) Q. robur(2) (Degen, Streiff, & Ziegenhagen, 1999) Q. suber(1) (Jiménez, Agundez, Alia, & Gil, 1999) Q. petraea(2) (Bruschi, Vendramin, Bussotti, & Grossoni, 2000) Q. pubescens(1) (Bruschi et al, 2000) Q. petraea(3) (Gömöry, Yakovlev, Zhelev, Jedináková, & Paule, 2001) Q. robur(3) (Gömöry et al, 2001) Q. petraea(4) (Mariette, et al, 2002) Q. robur(4) (Mariette et al, 2002) Q. shumardii (Aldrich et al, 2003) Q. palustris (Aldrich et al, 2003) Q. robur(5) (Muir & Schlötterer, 2005) Q. petraea(5) (Muir & Schlötterer, 2005) Q. aquifolioides (Zhang, Korpelainen, & Li, 2006) Q. suber(2) (Lopez-Aljorna, Bueno, Aguinagalde, & Martin, 2007) Q. gemminata(1) (Cavender- Bares & Pahlich, 2009) Q. virginiana(1) (Cavender- Bares & Pahlich, 2009) Q. engelmannii (Ortego, Riordan, Gugger, & Sork, 2012) Q. suber 3 Q. liaotungensis (Wang et al, 2014) Q. lobata (Ashley, Abraham, Backs, & Koenig, 2015) Q. petraea(6) (Curtu, Craciunesc, Enescu, Vidalis & Sofletea, 2015) Q. robur(6) (Curtu et al, 2015) Q. pubescens(2) (Curtu et al, 2015) Q. frainetto (Curtu et al, 2015) Q. robur(7) (Moracho et al, 2016) Q. robur(8) (Pohjanmies et al, 2016) Q. rubra (Sullivan, Owusu, Weber, Hipp, & Gailing, 2016) Q. ellipsoidalis (Sullivan et al, 2016) Q. coccinea (Sullivan et al, 2016) Q. velutina (Sullivan et al, 2016) Q. infectoria Q. mulleri …”