Professor Susanne Renner, Ludwig-Maximilians-Universität München
Are asymmetric invasion patterns in the Northern hemisphere explained by phenological differences among the woody plants of Asia, Europe, and North America? Hmm…
Many more woody species from East Asia and Europe are invasive in the Eastern United States than the other way around, and this asymmetric invasion success has been linked to earlier leaf-out in spring or longer growing seasons of Asian and European species compared to Americans (e.g., Harrington et al. 1989; Xu et al. 2007; Fridley 2012, Nature 485, 359–362; Laube et al. 2014; Polgar et al. 2014). The evolutionary mechanisms determining growing season length (GSL), i.e., the period between bud break and chlorophyll breakdown, however, are understudied. Thus, any innate GSL differences between Eastern North American, European, and East Asian species have neither been experimentally tested nor explained, nor is it known whether GSLs differ between introduced species that become invasive and those that do not (obviously answering these questions requires controlling for phylogeny). Constantin Zohner and I have analysed GSLs in 396 woody species grown in a common garden and found that Eastern North American species on average have a three-week shorter growing season than East Asian and European species, in part because they leaf out 13 ± days later, in part because they break down their chlorophyll 11 ± 4 days earlier. In my talk, I will provide a historical explanation for this finding and answer the question posed in the title.
Zohner, C. M.. B. M. Benito, J-C. Svenning, and S. S. Renner. 2016. Day length unlikely to constrain climate-driven shifts in leaf-out times of northern woody plants Nature Climate Change 6: 1120-1123.
Zohner, C. M., B. M. Benito, J. D. Fridley, J.-C. Svenning, and S. S. Renner. 2017. Spring predictability explains different leaf-out strategies in the woody floras of North America, Europe, and East Asia. Ecology Letters, in press
Zohner, C. M., and S. S. Renner. North American species have innate shorter growing seasons than Eurasian species, explaining native/non-native phenological asymmetries (in review)