Genetic diversity and population structure of boreal white spruce (Picea glauca) in pristine conifer-dominated and mixedwood forest stands

Abstract

White spruce ( Picea glauca (Moench) Voss) is a characteristic primary species of the Canadian boreal forest region, where it occurs in conifer-dominated and mixedwood forest types. Genetic diversity and population structure of white spruce may differ between the conifer-dominated and mixedwood forest types owing to the inherent differences in stand structure and dynamics. The objective of our study was to determine genetic diversity and population structure of pristine white spruce stands as they occur in conifer-dominated and mixedwood forest types at the EMEND (Ecosystem Management Emulating Natural Disturbance) study sites in northern Alberta. Nuclear microsatellite DNA markers were used to examine genetic diversity and population structure of 16 pristine natural old-growth (≥100 years) white spruce stands (subpopulations) of fire origin; 8 from conifer-dominated and 8 from neighboring mixedwood forest types. High levels of genetic diversity were observed, as expected. The genetic diversity and genetic constitution of white spruce were similar between the conifer-dominated and mixedwood forest types. Most of the genetic variation resided within subpopulations, with only about 2% genetic differentiation detected among 16 subpopulations as well as among 8 subpopulations within the same forest type. The mean genetic distances among subpopulations within and between the forest types were similar. Our study suggests that white spruce genetic resources are similar in the conifer-dominated and mixedwood forest types located in the EMEND study area in northern Alberta, and it provides the benchmarks for determining and monitoring the genetic diversity impacts of forest harvesting and forest fires.

Genetic Sustainability of Fragmented Conifer Populations from Stressed Areas in Northern Ontario (Canada): Application of Molecular Markers

“…Overall, the genetic distance analysis showed a high level of homogeneity among populations which could be due to the species characteristics. In fact, the relative small genetic distance values reported in the present analysis are consistent with other studies on Picea glauca populations in various provinces that used various molecular markers and allozymes (Rajora et al, 2005;Tremblay and Simon, 1989;Alden and Loopstra, 1987). In general, the genetic similarity among the populations suggests that these populations could have originated from a common source.…”

“…The fact that Picea glauca populations are fairly distributed should promote the exchange of genes among populations. Hence, it is rare to find alleles that are unique to a given populations, and the frequencies of the main alleles are generally similar from one population to another (Rajora et al, 2005;Tremblay and Simon, 1989;Alden and Loopstra, 1987).…”

Estimation of population structure in coastal Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] using allozyme and microsatellite markers

“…The mean number of alleles, observed and expected heterozygosities for SSR loci (A=11-36; H o =0.549-0.718; H e =0.877-0.944; see Electronic supplementary materials, Appendix 1) were also relatively higher than those estimated with the same type and number of markers in conifers with wide geographical distributions, such as Larix occidentalis (A=5.5, H o =0.521, H e =0.580; Khasa et al 2006), Pinus strobus (A=9.6, H o =0.522, H e =0.607; Rajora et al 2000;Marquardt and Epperson 2004), Pinus contorta (A=21.0, H e =0.425; Thomas et al 1999), Picea glauca (A=16.4, H o =0.649, H e =0.851; Rajora et al 2005), and also P. menziesii (A=7.5, H e =0.673; Amarasinghe and Carlson 2002) studied earlier. The difference can be explained by the fact that the SSR loci in our study were preselected as the most polymorphic.…”

Process to extinction and genetic structure of a threatened Japanese conifer species,Picea koyamae

“…Low F IS values have been reported for other Picea spp., such as P. alcoquiana (0.018; Aizawa et al 2008), P. asperata (0.005; Luo et al 2005), P. breweriana (0.003; Ledig et al 2005), P. mariana (-0.025; Gamache et al 2003;0.02;Perry and Bousquet 2001) and P. rubens (0.021; Rajora et al 2000). In addition, significantly positive F IS values have been reported for P. chihuahuana (0.185; Ledig et al 1997), P. glauca (0.226; Rajora et al 2005) and P. sitchensis in peripheral areas (0.17; . A clear relationship is not shown between the (Table 4) indicate that any population of P. koyamae that was derived from a small number of related individuals in core or peripheral areas might increase the degree of inbreeding.…”

“…Although the analysis of BOTTLENECK indicated that these populations have not experienced a recent reduction in effective population size, it does not deny that they experienced bottlenecks in the far past. Some populations of Picea have shown high fixation indices (Ledig et al 1997;Rajora et al 2005) and the existence of selfing (Innes and Ringius 1990;Ledig et al 2000;Flores-Lopéz et al 2005). These results suggest that over several generations, small and isolated populations of P. koyamae have survived with little gene flow, and have sustained themselves while increasing the degree of inbreeding.…”