Spatial Genetic Structure in Natural Populations of Phragmites australis in a Mosaic of Saline Habitats in the Yellow River Delta, China

Abstract

Determination of spatial genetic structure (SGS) in natural populations is important for both theoretical aspects of evolutionary genetics and their application in species conservation and ecological restoration. In this study, we examined genetic diversity within and among the natural populations of a cosmopolitan grass Phragmites australis (common reed) in the Yellow River Delta (YRD), China, where a mosaic of habitat patches varying in soil salinity was detected. We demonstrated that, despite their close geographic proximity, the common reed populations in the YRD significantly diverged at six microsatellite loci, exhibiting a strong association of genetic variation with habitat heterogeneity. Genetic distances among populations were best explained as a function of environmental difference, rather than geographical distance. Although the level of genetic divergence among populations was relatively low (F’ST = 0.073), weak but significant genetic differentiation, as well as the concordance between ecological and genetic landscapes, suggests spatial structuring of genotypes in relation to patchy habitats. These findings not only provided insights into the population dynamics of common reed in changing environments, but also demonstrated the feasibility of using habitat patches in a mosaic landscape as test systems to identify appropriate genetic sources for ecological restoration.

What's the meaning of local? Using molecular markers to define seed transfer zones for ecological restoration in Norway

“…Studies published so far focus on single species restoration (e.g. Gao et al 2012;Gibbs et al 2012;Michalski and Durka 2012) or on regional scale (e.g. Krauss and Koch 2004;Krauss and He 2006;Malaval et al 2010).…”

Increased invasive potential of non‐native Phragmites australis: elevated CO2 and temperature alleviate salinity effects on photosynthesis and growth

“…The EU-type as well as the Delta-type occur in the inner marshes and in the upper less saline parts of the delta wetlands (personal observation). A field investigation has shown that increasing soil salinity was negatively correlated with the genetic diversity within natural P. australis populations, pointing to distinct environmental optima that affect fitness, as important factors for microenvironmental selection of individual genotypes (Gao et al, 2012).…”

Contribution of genetics to ecological restoration

“…Landscape genetics was used (although rarely) as an additional and informative approach to determine whether population differentiation is best explained as a function of environmental differences rather than geographical distances (Gao et al . ), ultimately allowing the identification of appropriate source populations.…”

“…Studies used a wide variety of methods to delineate seed transfer zones, including analysis of molecular variance (Krauss & He 2006), principal component analysis (Lloyd et al 2011), clustering methods (Broadhurst 2011), spatial autocorrelation (Krauss & Koch 2004), isolation by distance calculated through Mantel tests (Gonzalo-Turpin et al 2010) and estimation of gene flow (Tanaka et al 2011). Landscape genetics was used (although rarely) as an additional and informative approach to determine whether population differentiation is best explained as a function of environmental differences rather than geographical distances (Gao et al 2012), ultimately allowing the identification of appropriate source populations.…”