Functional Traits Explain Variation in Chaparral Shrub Sensitivity to Altered Water and Nutrient Availability

Area of Science:

• Ecology
• Plant Biology
• Environmental Science

Background:

• Drylands face resource availability changes due to global environmental shifts.
• Functional traits can predict species' responses to altered nutrient and water availability.
• Existing research often overlooks traits related to nutrient budgets and allocation.

Purpose of the Study:

• To compare functional trait responses in serpentine and nonserpentine congener pairs from California chaparral.
• To investigate how plants respond to contrasting soil nutrient and moisture conditions.
• To integrate mineral nutrition traits into functional trait frameworks for understanding environmental change responses.

Main Methods:

• Common garden greenhouse experiment with six plant species (Arctostaphylos, Ceanothus, Quercus).
• Contrasting soil nutrient and moisture treatments were applied.
• Measured physiological, growth, and mineral nutrient traits, including nutrient use efficiency.

Main Results:

• Plant growth and phosphorus use efficiency were highest in low water, high nutrient conditions.
• Species variation and plasticity were linked to mineral nutrition traits, not biomass allocation or specific leaf area.
• Nonserpentine species showed greater plasticity and biomass response to resource addition than serpentine species.

Conclusions:

• Mineral nutrition-based traits, including nutrient allocation and use efficiency, are crucial for predicting species' responses to environmental change.
• Faster-growing species allocate more nitrogen and phosphorus to leaves and have higher phosphorus use efficiency.
• Understanding these traits helps explain species' varying sensitivity to anthropogenic changes in soil resource availability.