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Published on: January 11, 2015
Predicting ecological consequences of marine top predator declines
Michael R Heithaus1, Alejandro Frid, Aaron J Wirsing
1Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA. heithaus@fiu.edu
Trends in Ecology & Evolution
|March 1, 2008
Summary
Marine top predator declines trigger ecological cascades. Effective conservation requires managing predators for both direct mortality and behavioral risk effects on prey.
Area of Science:
- Marine ecology and conservation biology
- Trophic cascade dynamics
- Predator-prey interactions
Background:
- Significant declines in marine top predators are occurring globally.
- These declines can initiate trophic cascades, altering entire ecosystems.
- Predator impacts include direct mortality and indirect behavioral changes in prey (risk effects).
Purpose of the Study:
- To outline the direct and indirect consequences of marine predator declines.
- To propose an integrated framework for predicting ecological impacts, including risk effects.
- To inform management strategies for marine predator conservation.
Main Methods:
- Review and synthesis of existing studies on marine predator impacts.
- Development of a conceptual framework integrating mortality and risk effects.
- Analysis of factors influencing the strength of risk effects (e.g., prey lifespan, resource availability).
Main Results:
- Both predator-inflicted mortality and risk effects are crucial in marine communities.
- Focusing solely on mortality underestimates predator importance.
- Risk effects are strongest in long-lived prey species and under high resource conditions.
Conclusions:
- Marine predators must be managed to maintain both density- and risk-driven ecological processes.
- Conservation efforts should not solely focus on predator population numbers (demographic persistence).
- An integrated approach is necessary for effective marine ecosystem management.
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