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Multivariate selection mediated by aridity predicts divergence of drought-resistant traits along natural aridity gradients of an invasive weed

journal contribution
posted on 2024-11-02, 20:34 authored by Carter Carvalho, Rochelle Davis, Tim Connallon, Roslyn Gleadow, Joslin Moore, Akane UesugiAkane Uesugi
Geographical variation in the environment underpins selection for local adaptation and evolutionary divergence among populations. Because many environmental conditions vary across species' ranges, identifying the specific environmental variables underlying local adaptation is profoundly challenging. We tested whether natural selection mediated by aridity predicts clinal divergence among invasive populations of capeweed (Arctotheca calendula) that established and spread across southern Australia during the last two centuries. Using common garden experiments with two environmental treatments (wet and dry) that mimic aridity conditions across capeweed’s invasive range, we estimated clinal divergence and effects of aridity on fitness and multivariate phenotypic selection in populations sampled along aridity gradients in Australia. We show that: (1) capeweed populations have relatively high fitness in aridity environments similar to their sampling locations; (2) the magnitude and direction of selection strongly differs between wet and dry treatments, with drought stress increasing the strength of selection; and (3) differences in directional selection between wet and dry treatments predict patterns of clinal divergence across the aridity gradient, particularly for traits affecting biomass, flowering phenology and putative antioxidant expression. Our results suggest that aridity-mediated selection contributes to trait diversification among invasive capeweed populations, possibly facilitating the expansion of capeweed across southern Australia.

Funding

Evolution of chemical warfare in invasive plants

Australian Research Council

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History

Journal

New Phytologist

Volume

234

Issue

3

Start page

1088

End page

1100

Total pages

13

Publisher

Wiley-Blackwell Publishing

Place published

United Kingdom

Language

English

Copyright

© 2022 The Authors New Phytologist © 2022 New Phytologist Foundation This is an open access article under the terms of the Creative Commons Attribution License

Former Identifier

2006115806

Esploro creation date

2022-06-05

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