2017 ESA Annual Meeting (August 6 -- 11)

PS 26-118 - Woody seed plants show two contrasting drought survival strategies: desiccation tolerance and avoidance

Tuesday, August 8, 2017
Exhibit Hall, Oregon Convention Center
Liang Wei1, Chonggang Xu2, Hang Zhou3, Bradley Christofferson1, Steven Jansen4, William T. Pockman5, Richard S. Middleton1 and Nathan G. McDowell6, (1)Earth and Environment Sciences, Los Alamos National Lab, Los Alamos, NM, (2)Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, (3)Department of Geography, University of Idaho, Moscow, ID, (4)Institut für Systematische Botanik und Ökologie, Universität Ulm, Ulm, Germany, (5)Department of Biology, University of New Mexico, Albuquerque, NM, (6)Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM
Background/Question/Methods

Drought-associated woody plant mortality is expected to increase with global warming. Accurate prediction requires understanding of how woody plants’ drought strategies enable survival under different environmental conditions. Woody plants survive the drought through multiple strategies, but comprehensive knowledge is lacking regarding these strategies, precluding process-based modeling of vegetation survival under novel climate conditions. We constructed a simple survival-trait system to group freestanding woody plants (tree and shrub) species based on how they survive in multidimensional environmental spaces with their variable traits for temperate species of the Northern Hemisphere. We performed cluster analysis using the “mclust” package in R to automatically search for groups based on plant traits and their tolerance to light and drought

Results/Conclusions

We found a clear separation of temperate woody species into two groups with contrasting drought strategies based on species’ mean xylem embolism resistance, shade tolerance, and habitat aridity: desiccation tolerators and desiccation avoiders. The embolism resistance of desiccation tolerators is coordinated with habitat aridity while a tradeoff exists between shade tolerance and habitat aridity. Desiccation avoiders may have both low shade tolerance and low embolism resistance, but some can survive in particularly arid environments through embolism-avoiding strategies rather than via embolism resistant xylem. Our results demonstrate how two woody plant groups differ clearly in drought responses and how plant traits are related to such drought responses. We anticipate the two-group separation to be a new framework for studying plant traits that will benefit understanding and modeling of plants’ drought responses.