Hydrothermal physiology and climate vulnerability in amphibians

Area of Science:

• Ecology
• Physiology
• Climate Change Biology

Background:

• Global climate change necessitates understanding organismal responses to environmental shifts.
• Organismal thermal physiology is crucial, but the combined effects of temperature and hydration on performance are understudied, particularly in amphibians.

Purpose of the Study:

• To investigate the interplay between functional performance, hydration state, and temperature in three amphibian species.
• To determine how temperature and water loss concurrently limit amphibian activity.

Main Methods:

• Empirical measurement of functional performance across varying hydration states and temperatures.
• Development of species-specific biophysical models integrating hydrothermal performance data.

Main Results:

• Amphibian performance remained stable until a critical dehydration threshold (20-30% mass loss), after which it declined rapidly.
• Warmer temperatures accelerated performance decline due to dehydration.
• Biophysical models indicated dehydration could restrict activity up to 60% more than temperature alone.

Conclusions:

• Hydration physiology is a critical factor in predicting amphibian responses to climate change.
• Current climate vulnerability assessments may underestimate risks by not integrating hydration physiology.
• Future conservation strategies must consider both thermal and hydric stress for amphibians.