Abstract
The seasonal growth advantage hypothesis posits that plant species that grow well during seasonal drought will increase in abundance in forests with increasing seasonality of rainfall both in absolute numbers and also relative to co-occurring plant species that grow poorly during seasonal drought. That is, seasonal drought will give some plant species a growth advantage that they lack in aseasonal forests, thus allowing them attain higher abundance. For tropical forest plants, the seasonal growth advantage hypothesis may explain the distribution of drought-adapted species across large-scale gradients of rainfall and seasonality. We tested the seasonal growth advantage hypothesis with lianas and trees in a seasonal tropical forest in central Panama. We measured the dry-season and wet-season diameter growth of 1,117 canopy trees and 648 canopy lianas from 2011 to 2016. We also evaluated how lianas and trees responded to the 2015-2016 El Niño, which was the third strongest el Niño drought on record in Panama. We found that liana growth rate was considerably higher during the dry-season months than the wet-season months in each of the five years. Lianas achieved one-half of their annual growth during the 4-month dry season. By contrast, trees grew far more during the wet season; they realized only one-quarter of their annual growth during the dry season. During the strong 2015-2016 El Niño dry season, trees essentially stopped growing, whereas lianas grew unimpeded and as well as during any of the previous four dry seasons. Our findings support the hypothesis that seasonal growth gives lianas a decided growth advantage over trees in seasonal forests compared to aseasonal forests, and may explain why lianas peak in both absolute and relative abundance in highly seasonal tropical forests. Furthermore, the ability of lianas to grow during a strong el Niño drought suggests that lianas will benefit from the predicted increasing drought severity, whereas trees will suffer, and thus lianas are predicted to increase in relative abundance in seasonal tropical forests.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.