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Updated: Apr 28, 2026

Predicting the Effectiveness of Population Replacement Strategy Using Mathematical Modeling
Published on: July 4, 2007
Commentary on Holmes et al. (2007): resolving the debate on when extinction risk is predictable
Stephen P Ellner1, Elizabeth E Holmes
1Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-2701, USA. spe2@cornell.edu
This study reconciles narrow quasi-extinction risk confidence intervals with theory predicting wide ones. It provides an approximation for precise population viability analysis (PVA) estimates, defining safety, danger, and uncertainty regions.
Area of Science:
- Ecology
- Conservation Biology
- Population Dynamics
Background:
- Previous theory predicted wide confidence intervals for quasi-extinction risk.
- Holmes et al. observed narrow confidence intervals for many vertebrates of conservation concern.
- Reconciling these differing observations is crucial for accurate conservation planning.
Discussion:
- This study extends population viability analysis (PVA) theory.
- It focuses on the precision of quasi-extinction estimates based on population parameters, prediction intervals, and thresholds.
- An approximation is developed to identify conditions yielding precise vs. imprecise estimates.
Key Insights:
- Developed an approximation to determine when quasi-extinction estimates are precise.
- Identified specific prediction interval and threshold combinations for precise estimates.
- Provides a framework for distinguishing between precise and imprecise PVA outcomes.
Outlook:
- Enables PVA practitioners to define regions of safety, danger, and uncertainty.
- Facilitates better-informed conservation decisions by clarifying risk assessment precision.
- Improves the reliability of quasi-extinction risk assessments for endangered species.
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