Mapping tree canopy thermal refugia for birds using biophysical models and LiDAR

Area of Science:

• Ecology and climate change biology
• Avian ecophysiology
• Landscape modeling

Background:

• Accurate prediction of animal exposure to climate change necessitates evaluating warming effects on microclimates.
• Birds utilize cool vegetation microsites during hot weather.
• Subtropical African savannas face increasing temperatures.

Purpose of the Study:

• To evaluate current and future availability of cool avian microsites in a savanna landscape.
• To model bird exposure to heat stress under climate change scenarios.

Main Methods:

• Combined LiDAR-based tree canopy mapping with biophysical modeling.
• Developed species-specific models for bulbul and hornbill.
• Modeled exposure to body temperatures exceeding 42°C.

Main Results:

• Currently, 34.5% of trees offer suitable cool microclimates for both species.
• Under RCP 8.5, cool microsite availability will plummet to 0.4% (bulbuls) and 3.8% (hornbills) by century's end.
• Exposure to temperatures >42°C will increase significantly for both species.

Conclusions:

• Savanna birds face drastic reductions in thermal refugia under a business-as-usual emissions scenario.
• Climate change poses a significant threat to avian populations in African savannas.
• Urgent mitigation strategies are needed to preserve critical avian habitats.