Thermal Decoupling May Promote Cooling and Avoid Heat Stress in Alpine Plants

Area of Science:

• Ecology
• Plant Physiology
• Climate Change Biology

Background:

• Alpine ecosystems face low temperatures, favoring prostrate growth for thermal resistance.
• Climate change and heatwaves may challenge the adaptive value of thermal decoupling in alpine plants.

Purpose of the Study:

• To evaluate how thermal decoupling (TD) influences heat resistance (LT50) in six alpine species.
• To understand the interplay between TD, environmental factors, and plant traits in alpine heat resistance.

Main Methods:

• Combined microclimatic and plant characterization.
• Utilized infrared thermal imaging and leaf photoinactivation.
• Assessed six alpine species from the Nevados de Chillán volcano complex.

Main Results:

• Most species exhibited negative TD, staying cooler than ambient air (mean difference of 6.7 K).
• Shorter, rounded plants showed stronger negative TD.
• All species displayed high heat resistance (mean LT50 = 46 °C), with shrubs showing a positive correlation between LT50 and TD.

Conclusions:

• Thermal decoupling is a key factor in alpine plant heat resistance, with variations across species and growth forms.
• Alpine plants possess significant heat resistance despite negative TD, highlighting adaptive strategies.
• Findings offer insights into alpine plant responses to climate change-induced heat stress.