Environment and physiology shape Arctic ungulate population dynamics.

Area of Science:

• Ecology and Conservation Biology
• Arctic Wildlife Dynamics
• Population Modeling

Background:

• Arctic ecosystems face rapid environmental changes due to global warming.
• Understanding species' responses to environmental shifts is crucial for conservation.
• Muskoxen populations are vulnerable to changes in forage availability and environmental conditions.

Purpose of the Study:

• To model the impact of environmental variables on muskox life history and population dynamics.
• To identify key drivers of seasonal energy storage and population fluctuations.
• To assess the long-term consequences of altered forage accessibility on muskox populations.

Main Methods:

• Developed a parameterized, full life cycle, individual-based energy budget model for muskoxen.
• Integrated year-round environmental data with detailed metabolic physiology.
• Simulated various scenarios of snow depth, plant biomass, and quality.

Main Results:

• Winter forage accessibility, determined by snow depth, was the primary factor influencing muskox population dynamics.
• Calf recruitment was highly sensitive to winter forage accessibility, with impacts ranging from ±10-80%.
• Snow-rich winters had cumulative, long-term effects on population growth and structure, with recovery times exceeding 10 years.

Conclusions:

• Alterations in winter forage accessibility, particularly snow depth, significantly impact northern herbivore population dynamics.
• The developed model provides a framework for assessing future environmental change scenarios on Arctic wildlife.
• Conservation strategies must consider the critical role of winter conditions and forage access for muskox survival and recovery.