Could clonality contribute to the northern survival of grey alder [Alnus incana (L.) Moench] during the Last Glacial Maximum?

Abstract

Reconstruction of the glacial and postglacial history of a species, including lifehistory traits, provides valuable insights into the relationships between ecological and genetic factors shaping phylogeographic patterns. Clonality appears as a trait of high importance for survival in northern refugia. In the present study, the phylogeographic structure of 24 Alnus incana (grey alder) populations and clonal structure in seven populations were analyzed utilizing four microsatellites markers. Palaeobotanical data were collected and combined with the genetic results in order to support the possibility that this species survived in northern refugia. Our study indicated that: (i) Balkan populations are the most divergent, which likely reflects their long-term in-situ existence, (ii) Western Alpine populations are genetically different from other European populations, which corresponds with palaeobotanical data, suggesting that this region served as a refugium for this species, (iii) the macrofossil data indicate that the Scandinavian and northeastern Polish populations are likely derived from the refugia located in northern latitudes, (iv) Western and Eastern Carpathian populations form separate groups, which indicate that both regions could serve as refugia. Clonality was an important factor in allowing grey alder to survive in northern regions during the last glaciation. However, this mode of reproduction has also influenced the population genetic structure, as we noted rather low level of gene diversity, H E = 0.386 and low allelic variability, A = 3.8, in this species.

Genetic Diversity and Population Structure of Alnus cremastogyne as Revealed by Microsatellite Markers

“…Overall, the 14 A. cremastogyne populations all have relatively high levels of genetic diversity (Na = 5.83, Ht = 0.630), with the Liangshan Prefecture populations (Meigu, Mianning) and Ganzi population (Luding) having the highest level of genetic diversity. Based on the SSR data, the genetic diversity of A. cremastogyne is higher than that of A. maritima (Na = 4.70, He = 0.45) [11] and A. incana (Na = 3.31, He = 0.386) [41]. Meanwhile, the genetic diversity of A. cremastogyne is similar to that of the whole European population (Na = 6.70, He = 0.643) [35], the Irish, Scottish, and French population (Na = 6.61, He = 0.64) [17], as well as that of A. glutinosa population located at the border of Belgium, Luxembourg, and France (Na = 7.34, He = 0.64) [41].…”

Tertiary remnants and Holocene colonizers: Genetic structure and phylogeography of Scots pine reveal higher genetic diversity in young boreal than in relict Mediterranean populations and a dual colonization of Fennoscandia

“…Both palaeobotanical and molecular data have provided evidence that southern margins of the European continent acted as refugia for many European tree species in Late Pleniglacial (LPG; 24–14.6 ka) during which the most extreme glacial conditions prevailed and the Scandinavian Ice Sheet (SIS) attained its maximal size. However, in the case of some species, a specific set of life history traits may have enabled them to maintain additional refugial populations sparsely distributed closer to the ice margins (Bhagwat & Willis, ; Dering, Latałowa, Boratyńska, Kosiński, & Boratyński, ). This idea of northern refugia has been a subject of vivid debate for over a decade, during which supporting arguments of enthusiasts and doubts of sceptics have been colliding (de Lafontaine, Amasifuen Guerra, Ducousso, & Petit, ; Parducci et al., ; Tzedakis, Emerson, & Hewitt, ; Willis & van Andel, ).…”

Genetic diversity and differentiation of the riparian relict tree <i>Pterocarya fraxinifolia</i> (Juglandaceae) along altitudinal gradients in the Hyrcanian forest (Iran)

“…The number of observed (Na) and effective alleles (Ne), observed and expected heterozygosity, inbreeding index, clonal structure and gene flow among the populations were calculated by the GenAlEx software (Peakall and Smouse 2006). Clonal structure in studied populations was calculated using genotype diversity according to the formula R = (G − 1)/(N − 1), where G is the number of total genotypes detected and N is the number of individuals collected along both river gradients (Dering et al 2017).…”

“…Moreover, multidirectional genetic diversity and allelic richness in all of the studied populations attests to sufficient gene flow and thus proves the genetic capacity of P. fraxinifolia to cope with environmental changes and global warming. In the case of the P. fraxinifolia population, growing along the Talar and Tajan rivers, we have not discovered a high level of clonality, typical for riparian species such as Alnus incana (L.) Moench (Dering et al 2017), Populus nigra (Barsoum et al 2004) or Populus euphratica Olivier, where in the most extreme situation a single genet can be determined (Sękiewicz, unpublished data). This occurs despite the severe degradation of the habitats of this species, especially in the plain region of the Hyrcanian region.…”