Print PageThe desert-chaparral transition represents an intersection of two major vegetation types in California and contains a mix of chaparral and desert shrubs, as well as endemic species that only occur along this margin. This vegetation boundary has large potential for drought-induced vegetation change because nearly all species are at the edge of their range. We studied 17 species to determine how drought avoidance and resistance strategies such as drought deciduousness, rooting depth, and vulnerability to xylem cavitation promote species co-existence in an arid ecosystem of considerable floristic complexity.
Results/Conclusions
We identified several major trade-offs in hydraulic strategies. Leaf area:sapwood area increased with xylem vulnerability illustrating a trade-off in hydraulic architecture. Species with high rates of hydraulic conductivity had greater vulnerability to xylem cavitation illustrating a trade-off between safety and efficiency of water transport. Rooting depth and minimum seasonal water potential also played key roles in determining plant strategies and likely contribute to species coexistence in this functionally diverse arid ecosystem.
