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Weak population regulation in ecological time series
Nicolas L Ziebarth1, Karen C Abbott, Anthony R Ives
1Department of Economics, Northwestern University, Evanston, IL 60202, USA.
Ecology Letters
|October 24, 2009
Summary
Many natural populations exhibit weak regulation, meaning their population sizes fluctuate significantly over time. This study analyzed ecological data, revealing that longer time series often indicate less regulated population dynamics.
Area of Science:
- Ecology
- Population Dynamics
- Statistical Ecology
Background:
- The degree of natural population regulation is a long-standing ecological question.
- Understanding population regulation is crucial for ecological management and conservation.
Purpose of the Study:
- To investigate population regulation in natural populations using stochastic dynamics.
- To quantify population regulation metrics and assess their empirical prevalence.
Main Methods:
- Discussed concepts of population regulation for stochastic dynamics.
- Analyzed large ecological datasets using autoregressive-moving average (ARMA) models.
- Employed model selection to identify best-fitting models and estimated population regulation metrics.
Main Results:
- Longer ecological time series were associated with weaker population regulation.
- Over 35% of datasets (length >= 20) showed characteristic return times exceeding 6 years.
- Nearly 30% of datasets exhibited stationary distribution variability significantly higher than maximal regulation.
Conclusions:
- Empirical evidence suggests many natural populations are weakly regulated.
- Population dynamics may be less predictable than often assumed.
- The findings have implications for ecological forecasting and management strategies.
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