Cumulative adversity and survival in the wild

Area of Science:

• Ecology and evolutionary biology
• Wildlife population dynamics
• Environmental stress research

Background:

• Assessing the impact of multiple early-life stressors on natural populations is complex.
• Cumulative risk models, successful in human health, offer a potential framework for ecological studies.
• Wild yellow-bellied marmots (Marmota flaviventer) serve as a model organism for this research.

Purpose of the Study:

• To adapt and apply cumulative adversity indices (CAIs) to a wild mammal population.
• To investigate the relationship between cumulative early-life adversity and fitness indicators (pup survival, lifespan).
• To evaluate the utility of CAI models compared to traditional multivariate approaches.

Main Methods:

• Development and testing of various cumulative adversity indices (CAIs) across different stressor types and time windows.
• Analysis of CAIs in relation to pup survival and adult lifespan in a wild yellow-bellied marmot population.
• Comparison of CAI model performance against multivariate models incorporating factors like weaning date and environmental variables.

Main Results:

• All tested CAIs were significantly associated with decreased pup survival.
• Moderate and acute CAIs, but not standardized CAIs, correlated with reduced lifespan.
• CAI models demonstrated superior predictive power for lifespan compared to multivariate models.

Conclusions:

• The cumulative stress hypothesis is supported in wild yellow-bellied marmots, showing the enduring effects of early adversity.
• CAI approaches provide a powerful and insightful framework for ecological and conservation research on stress impacts.
• This study highlights the development and utility of CAI for understanding population fitness under multiple stressors.