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Updated: Jun 23, 2026
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Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter
Published on: March 12, 2013
Cascading extinctions and community collapse in model food webs
Jennifer A Dunne1, Richard J Williams
1Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA. jdunne@santafe.edu
Summary
Ecosystems face secondary extinctions from species loss. Realistic food-web models show increased diversity and complexity enhance robustness against species removals, unlike simpler models.
Area of Science:
- Ecology
- Theoretical Ecology
- Food Web Dynamics
Background:
- Species loss can trigger secondary extinctions through complex ecological interactions.
- Understanding food web structure is crucial for predicting ecosystem stability and resilience.
Purpose of the Study:
- To compare secondary extinction levels across different food-web structural models.
- To assess the impact of species loss sequences on food-web integrity.
- To relate structural integrity metrics to model assumptions, diversity, and complexity.
Main Methods:
- Simulated sequential primary species removals in five distinct food-web models (four structural, one null).
- Analyzed food-web structural integrity, including robustness, community collapse, and threshold periods.
- Examined relationships between structural integrity and measures of diversity (species richness S) and complexity (connectance C).
Main Results:
- Hierarchical feeding structures, while realistic, can reduce food-web robustness.
- Exponential link distributions in realistic models generally enhance structural robustness compared to less skewed distributions.
- Increased species richness (S) and connectance (C) in realistic models correlate with greater robustness and less community collapse.
- Realistic models show unexpected sensitivity to the removal of species with few links.
Conclusions:
- Food-web structure significantly influences secondary extinction dynamics and ecosystem resilience.
- Realistic food-web models incorporating exponential link distributions offer greater robustness.
- Diversity and complexity are key factors in maintaining food-web structural integrity against species loss.
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