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.