Eco-evolutionary processes underlying early warning signals of population declines

Area of Science:

• Ecology
• Evolutionary Biology
• Population Dynamics

Background:

• Environmental changes can destabilize ecosystems and cause population declines.
• Early warning signals (EWS) based on population abundance have limited success in predicting wild population collapses.
• Trait-based EWS, focusing on shifts in fitness-related traits like body size, are emerging as alternatives.

Purpose of the Study:

• To investigate how ecological and evolutionary factors affect population stability and the detectability of abundance- and trait-based EWS.
• To explore the influence of reproductive rate, genetic variation, and plasticity on population dynamics under environmental change.
• To assess the combined predictive power of trait and abundance data for forecasting population declines.

Main Methods:

• Applied a trait-based demographic approach to analyze population and trait dynamics.
• Investigated population responses to gradual and increasing environmental changes.
• Utilized analytical methods and simulations to explore ecological and evolutionary constraints.

Main Results:

• Both abundance- and trait-based EWS are significantly influenced by ecological and evolutionary factors.
• The strength of these warning signals varies depending on underlying population characteristics.
• Combining trait dynamics with abundance data enhances the accuracy of predicting population declines.

Conclusions:

• Ecological and evolutionary factors critically shape population stability and the effectiveness of EWS.
• Integrating trait information with traditional abundance-based signals offers a more robust approach to forecasting ecological futures.
• This integrated approach promises more accurate predictions of biological system states.