Climate-Induced Physiological Stress Drives Rainforest Mammal Population Declines

Area of Science:

• Ecology
• Climate Change Biology
• Conservation Science

Background:

• Climate change is a primary driver of biodiversity loss globally.
• The specific mechanisms linking climate change to population declines in mammals are not well understood.
• Previous models often fail to integrate physiological constraints with population dynamics.

Purpose of the Study:

• To develop and apply a novel modeling framework to understand climate change impacts on mammalian herbivore populations.
• To investigate the causes of population declines in two species of Australian ringtail possums (Pseudochirops archeri and Hemibelideus lemuroides).
• To bridge the gap between mechanistic and statistical modeling approaches for ecological studies.

Main Methods:

• Integrated biophysical, nutritional, and population modeling.
• Quantified species-specific temperature and water stress, and foraging limitations.
• Linked physiological constraints with 30-year population monitoring data and nutritional quality using an open population model.

Main Results:

• Climate change impacts possum populations through physiological stress in a species-specific manner.
• Both Pseudochirops archeri and Hemibelideus lemuroides experienced population collapses at lower elevations and in low-nutritional sites.
• Pseudochirops archeri declines were linked to reduced survival (overheating, dehydration) and recruitment (limited foraging); Hemibelideus lemuroides declines were primarily linked to foraging constraints.

Conclusions:

• Climate change affects possum populations via direct physiological stress and indirect foraging limitations.
• Understanding species-specific responses is crucial for effective conservation.
• The developed framework provides mechanistic insights for targeted conservation strategies against climate change impacts.