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Evidence that divergent selection shapes a developmental cline in a forest tree species complex


Costa e Silva, J and Harrison, PA and Wiltshire, R and Potts, BM, Evidence that divergent selection shapes a developmental cline in a forest tree species complex, Annals of Botany, 122, (1) pp. 181-194. ISSN 0305-7364 (2018) [Refereed Article]

Copyright Statement

The Author(s) 2018. All rights reserved.

DOI: doi:10.1093/aob/mcy064


Background and Aims: Evolutionary change in developmental trajectories (heterochrony) is a major mechanism of adaptation in plants and animals. However, there are few detailed studies of the variation in the timing of developmental events among wild populations. We here aimed to identify the climatic drivers and measure selection shaping a genetic-based developmental cline among populations of an endemic tree species complex on the island of Tasmania.

Methods: Seed lots from 38 native provenances encompassing the clinal transition from the heteroblastic Eucalyptus tenuiramis to the homoblastic Eucalyptus risdonii were grown in a common-garden field trial in southern Tasmania for 20 years. We used 27 climatic variables to model the provenance variation in vegetative juvenility as assessed at age 5 years. A phenotypic selection analysis was used to measure the fitness consequences of variation in vegetative juvenility based on its impact on the survival and reproductive capacity of survivors at age 20 years.

Key Results: Significant provenance divergence in vegetative juvenility was shown to be associated with home-site aridity, with the retention of juvenile foliage increasing with increasing aridity. Our results indicated that climate change may lead to different directions of selection across the geographic range of the complex, and in our mesic field site demonstrated that total directional selection within phenotypically variable provenances was in favour of reduced vegetative juvenility.

Conclusions: We provide evidence that heteroblasty is adaptive and argue that, in assessing the impacts of rapid global change, developmental plasticity and heterochrony are underappreciated processes which can contribute to populations of long-lived organisms, such as trees, persisting and ultimately adapting to environmental change.

Item Details

Item Type:Refereed Article
Keywords:heteroblasty, heterophylly, ontogeny, heterochrony, neoteny, vegetative juvenility, provenance variation, phenotypic selection, climate change, aridity, Eucalyptus risdonii, Eucalyptus tenuiramis
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Ecological impacts of climate change and ecological adaptation
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Harrison, PA (Dr Peter Harrison)
UTAS Author:Wiltshire, R (Dr Robert Wiltshire)
UTAS Author:Potts, BM (Professor Brad Potts)
ID Code:126982
Year Published:2018
Web of Science® Times Cited:9
Deposited By:Plant Science
Deposited On:2018-07-05
Last Modified:2019-03-26

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