Cold waves in the Amazon rainforest and their ecological impact.

Area of Science:

• Ecology
• Climate Change Biology
• Zoology

Background:

• Cold waves in the Amazon rainforest are rare but impactful events.
• Climate change may alter the frequency and intensity of these extreme weather phenomena.
• Understanding the impact of cold waves on Amazonian fauna is crucial for conservation.

Purpose of the Study:

• To document an extensive cold wave in the Amazonian-Andean forests in June 2023.
• To assess the impact of this cold wave on lowland insect and wild mammal communities.
• To compare environmental temperatures with the experimentally determined thermal tolerances of these animals.

Main Methods:

• Monitoring environmental temperatures during the June 2023 cold wave.
• Measuring the thermal tolerance limits of Amazonian lowland animals (insects and mammals).
• Analyzing animal activity abundance and insect biomass before and after the cold wave.

Main Results:

• A significant reduction in the activity abundance of all studied animal groups was observed during the cold wave.
• Tropical lowland animals exhibited thermal tolerance limits lower than the minimum temperatures recorded.
• While mammal activity and most insect biomass recovered, dung beetle biomass remained depressed post-cold wave.

Conclusions:

• The study highlights the vulnerability of Amazonian lowland fauna to extreme cold events.
• A quarter of insect species had narrow thermal safety margins, indicating high sensitivity to cold.
• Increased cold wave intensity due to climate change could threaten cold-sensitive Amazonian animal communities.