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Molecular insights into the dynamics of species invasion by hybridisation in Tasmanian eucalypts


Pfeilsticker, TR and Jones, RC and Steane, DA and Vaillancourt, RE and Potts, BM, Molecular insights into the dynamics of species invasion by hybridisation in Tasmanian eucalypts, Molecular Ecology pp. 1-17. ISSN 1365-294X (2023) [Refereed Article]

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Copyright Statement

2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs (CC BY 4.0) License, ( which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

DOI: doi:10.1111/mec.16892


In plants where seed dispersal is limited compared with pollen dispersal, hybridisation may enhance gene exchange and species dispersal. We provide genetic evidence of hybridisation contributing to the expansion of the rare Eucalyptus risdonii into the range of the widespread E. amygdalina. These closely related tree species are morphologically distinct, and observations suggest that natural hybrids occur along their distribution boundaries and as isolated trees or in small patches within the range of E. amygdalina. Hybrid phenotypes occur outside the range of normal dispersal for E. risdonii seed, yet in some hybrid patches small individuals resembling E. risdonii occur and are hypothesised to be a result of backcrossing. Using 3,362 genome-wide SNPs assessed from 97 individuals of E. risdonii and E. amygdalina and 171 hybrid trees, we show that (i) isolated hybrids match the genotypes expected of F1/F2 hybrids, (ii) there is a continuum in the genetic composition among the isolated hybrid patches from patches dominated by F1/F2-like genotypes to those dominated by E. risdonii-backcross genotypes; and (iii) the E. risdonii-like phenotypes in the isolated hybrid patches are most-closely related to proximal larger hybrids. These results suggest that the E. risdonii phenotype has been resurrected in isolated hybrid patches established from pollen dispersal, providing the first steps in its invasion of suitable habitat by long-distance pollen dispersal and complete introgressive displacement of E. amygdalina. Such expansion accords with the population demographics, common garden performance data and climate modelling which favours E. risdonii and highlights a role of interspecific hybridisation in climate change adaptation and species expansion.

Item Details

Item Type:Refereed Article
Keywords:Eucalyptus amygdalina, Eucalyptus risdonii, dispersal mechanism, genetics, species expansion, climate change, admixture
Research Division:Biological Sciences
Research Group:Evolutionary biology
Research Field:Evolutionary biology not elsewhere classified
Objective Division:Plant Production and Plant Primary Products
Objective Group:Forestry
Objective Field:Native forests
UTAS Author:Pfeilsticker, TR (Ms Thais Ribeiro Pfeilsticker)
UTAS Author:Jones, RC (Dr Rebecca Jones)
UTAS Author:Steane, DA (Dr Dorothy Steane)
UTAS Author:Vaillancourt, RE (Professor Rene Vaillancourt)
UTAS Author:Potts, BM (Professor Brad Potts)
ID Code:155252
Year Published:2023
Funding Support:Australian Research Council (DP160101650)
Deposited By:Office of the School of Natural Sciences
Deposited On:2023-02-07
Last Modified:2023-03-20
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