Convergence in water use efficiency within plant functional types across contrasting climates

Area of Science:

• Ecology
• Remote Sensing
• Plant Physiology

Background:

• Water use efficiency (WUE) links plant carbon uptake and water loss, crucial for understanding ecosystem responses to climate.
• ECOSTRESS provides high-resolution thermal data for detailed WUE analysis.

Purpose of the Study:

• To analyze the spatial distribution of WUE using ECOSTRESS data across different plant functional types.
• To investigate if WUE converges to common global optima within specific plant functional types.

Main Methods:

• Utilized ECOSTRESS thermal radiometer data from the International Space Station.
• Analyzed Water Use Efficiency (WUE) data, focusing on distribution and convergence patterns.
• Compared WUE values across nine plant functional types globally.

Main Results:

• Despite local variability, WUE converged to common global optima for five plant functional types: grassland, permanent wetland, savannah, deciduous broadleaf, and deciduous needleleaf forests.
• This convergence was observed across diverse geographic regions and climates.
• Optimized WUE distributions showed low variance (<0.5 g C per kg H2O) and high kurtosis (>3.0).

Conclusions:

• Global plant functional types exhibit convergent water use efficiency patterns, indicating predictable ecosystem functions.
• ECOSTRESS data reveals universal optima in WUE, irrespective of geographic location or climate for certain vegetation types.
• These findings enhance our understanding of ecosystem function and climate interactions.