Author
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Gaskin, John |
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Submitted to: Annals of Botany
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/17/2016 Publication Date: 12/26/2016 Citation: Gaskin, J.F. 2016. The role of hybridization in facilitating tree invasion. Annals Of Botany. 9(1):plw079. doi:10.1093/aobpla/plw079. Interpretive Summary: Hybridization, the crossing of two different species, can generate additional genetic diversity and create invasive plant species. Invasive tree species are a growing ecological concern worldwide, and some of these invasions involve hybridization events. There are 19 hybrid invasive tree taxa in 14 genera (10 plant families) discussed here. Abundance of hybrids comprised an average of 54% of the invasion. Only in six hybrid taxa did researchers identify characteristics that may make hybrids better invaders. Nine hybrid tree taxa involved cross-breeding between hybrids and parents, and more hybrids involved all non-native taxa than native x non-native species. Ten hybrid species were the result of unintentional crosses rather than breeding programs, and all hybrid tree invasions involved intentional introduction of either one or more parental species or the hybrid itself. The knowledge gaps in some hybrid tree species can weaken our effectiveness in predicting and controlling invasions, as hybrids can add a level of complexity to control of an invasion by being hard to distinguish from parental species, causing genetic pollution of a native parental taxon, or moving adaptive traits from native to hybrid species through sexual reproduction. Technical Abstract: Hybridization events can generate additional genetic diversity on which natural selection can act and at times enhance invasiveness of the species. Invasive tree species are a growing ecological concern worldwide, and some of these invasions involve hybridization events pre- or post-introduction. There are 19 hybrid invasive tree taxa in 14 genera (10 plant families) discussed here. When reported, abundance of hybrids comprised an average of 54% of the invasion, the remainder being parental taxa. Only in six hybrid taxa did researchers identify phenotypes that may make hybrids better invaders. Nine hybrid tree taxa involved introgression, and more hybrids involved all non-native taxa than native x non-native taxa. Ten hybrid taxa were the result of unintentional crosses rather than breeding programs, and all hybrid tree taxa involve intentional introduction of either one or more parental taxon or the hybrid itself. The knowledge gaps in some hybrid tree taxa can weaken our effectiveness in predicting and controlling invasions, as hybrids can add a level of complexity to control of an invasion by being morphologically cryptic, causing genetic pollution of a native parental taxon, or assimilating adaptive traits from native to hybrid taxa through gene flow. |
