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Updated: Jul 10, 2026
12:24
Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout (Salvelinus namaycush) from Its Prey
Published on: August 29, 2014
Leading indicators of trophic cascades
S R Carpenter1, W A Brock, J J Cole
1Center for Limnology, University of Wisconsin, Madison, WI 53706, USA. srcarpen@wisc.edu
Ecology Letters
|November 21, 2007
Summary
Ecosystem regime shifts, or major changes, can be predicted by monitoring key variables. Early warning signals, like wider population swings, appear in food webs even before the shift occurs.
Area of Science:
- Ecology
- Environmental Science
- Systems Biology
Background:
- Ecosystems undergo abrupt and long-lasting regime shifts.
- These shifts are often unpredictable but may have detectable leading indicators.
- Early warning signals can include changes in population dynamics and recovery rates.
Purpose of the Study:
- To evaluate leading indicators of ecosystem regime shifts.
- To investigate if signals of impending regime shifts cascade through food webs.
- To determine if these signals are detectable in phytoplankton.
Main Methods:
- Utilized a food web model calibrated with long-term whole-lake experimental data.
- Simulated regime shifts driven by increased exploitation of top predators.
- Analyzed changes in standard deviations, return rates, and spectral properties of ecosystem variables.
Main Results:
- Significant changes in standard deviations, return rates, and spectra were observed near the regime shift point.
- These signals were detectable even in variables two trophic levels removed from the fish regime shift.
- Early warning signals can be discerned in phytoplankton, indicating cascading effects.
Conclusions:
- Leading indicators for ecosystem regime shifts are detectable in advance.
- Signals can be identified in lower trophic levels, such as phytoplankton, due to cascading effects.
- Further field validation of these ecological indicators is recommended.
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