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Published on: April 27, 2021
Regime shift indicators fail under noise levels commonly observed in ecological systems
Charles T Perretti1, Stephan B Munch
1Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, USA. cperrett@ucsd.edu
Summary
Early warning indicators for ecological regime shifts performed poorly in simulations of open systems with fluctuating noise. Rising variance was the most effective indicator, but more research is needed for real-world application.
Area of Science:
- Ecology
- Environmental Science
- Complex Systems
Background:
- Ecological regime shifts represent abrupt, long-lasting ecosystem state changes.
- Theoretical early-warning indicators exist but have limited empirical validation in open systems.
- Field studies often involve complex conditions like fluctuating noise and sparse data.
Purpose of the Study:
- To evaluate the performance of early-warning indicators for ecological regime shifts.
- To test indicators under realistic conditions of open ecological systems.
- To identify robust indicators for detecting impending regime shifts.
Main Methods:
- Utilized a three-species model simulating open ecological systems.
- Incorporated large correlated fluctuations in extrinsic noise.
- Applied a rapidly changing driving variable and sparsely sampled time series for indicator calculation.
Main Results:
- All tested early-warning indicators demonstrated poor performance.
- Indicator efficacy was particularly low at the onset of regime shifts.
- A rise in variance emerged as the most effective, though still limited, indicator.
Conclusions:
- Current early-warning indicators are unreliable under complex, open-system conditions.
- Future research must focus on establishing benchmark values for indicators.
- Developing indicators robust to sparsely sampled data is crucial for practical application.
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