Landscape genomics reveals altered genome wide diversity within revegetated stands of Eucalyptus microcarpa (Grey Box)

Abstract

In order to contribute to evolutionary resilience and adaptive potential in highly modified landscapes, revegetated areas should ideally reflect levels of genetic diversity within and across natural stands. Landscape genomic analyses enable such diversity patterns to be characterized at genome and chromosomal levels. Landscape-wide patterns of genomic diversity were assessed in Eucalyptus microcarpa, a dominant tree species widely used in revegetation in Southeastern Australia. Trees from small and large patches within large remnants, small isolated remnants and revegetation sites were assessed across the now highly fragmented distribution of this species using the DArTseq genomic approach. Genomic diversity was similar within all three types of remnant patches analysed, although often significantly but only slightly lower in revegetation sites compared with natural remnants. Differences in diversity between stand types varied across chromosomes. Genomic differentiation was higher between small, isolated remnants, and among revegetated sites compared with natural stands. We conclude that small remnants and revegetated sites of our E. microcarpa samples largely but not completely capture patterns in genomic diversity across the landscape. Genomic approaches provide a powerful tool for assessing restoration efforts across the landscape.

Evidence of genomic adaptation to climate in Eucalyptus microcarpa: Implications for adaptive potential to projected climate change

“…Results of the Mantel test (Mantel r = 0.738, p = .001) and ordination of the 4218 filtered SNPs indicated a clinal population structure, the latter reflecting E. microcarpa 's geographic distribution (Figure a). These support previous findings in this species (Jordan et al., ). The first axis (PC1) represented a strong latitudinal cline from central NSW to central Victoria, with the second axis (PC2) showing an east–west separation of western Victorian sites from more eastern central Victoria and southern NSW sites.…”

“…DNA was extracted from approximately 20 mg of freeze‐dried leaf material using a modified CTAB method as per Jordan, Dillon, Prober, and Hoffmann (). Approximately 400 ng of DNA per sample was sent in two batches to Diversity Arrays Technology Pty Ltd, Canberra, for individual Eucalyptus DArTseq, a reduced‐representation genomic approach (Sansaloni et al., ; see Supporting Information—Supplementary methods for further details).…”

Standing genomic variation within coding and regulatory regions contributes to the adaptive capacity to climate in a foundation tree species

“…Collectively, these studies highlight implications for future evolution and ecosystem management as widespread eucalypts are foundation species in forest and woodland ecosystems. Low differentiation is common among widespread Eucalyptus species due to high levels of gene flow and connectivity (Byrne, ; Dillon et al, ; Jordan, Dillon, Prober, & Hoffmann, ; Mora, Arriagada, Ballesta, & Ruiz, ; Steane et al, ; ). Similarly, analysis here shows low levels of population structure in C. calophylla , as illustrated by the high admixture among putative genetic clusters and low estimate of population differentiation that was similar to previous estimates using nuclear microsatellite markers ( F ST = 0.033; Sampson et al, ).…”

Landscape drivers of genomic diversity and divergence in woodland Eucalyptus

“…The applicability of these results and conclusions to future generations of these species is uncertain. Individuals from later generations show reduced but still high genetic and/or phenotypic diversity in recent studies of related Eucalyptus species (Broadhurst, ; Jordan, Dillon, Prober, & Hoffmann, ; Supple et al, ), although these studies examined planted individuals, either in provenance trials or revegetation efforts (Costa e Silva, Hardner, Tilyard, & Potts, ). Further research on the differences in genetic diversity between remnant stands and younger cohorts is warranted.…”