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Temporal variation, dormancy, and coexistence: a field test of the storage effect
1Section of Ecology and Systematics, Corson Hall, Cornell University, Ithaca, NY 14853, USA.
Summary
The storage effect, involving long-lived eggs and environmental fluctuations, allows competing zooplankton (Daphnia) to coexist. This ecological mechanism is crucial for Daphnia galeata mendotae persistence, while Daphnia pulicaria relies on consistent recruitment.
Area of Science:
- Ecology
- Population Dynamics
- Environmental Science
Background:
- Theoretical models propose the "storage effect" allows competitors to coexist in fluctuating environments.
- Empirical evidence for the storage effect in natural populations remains limited.
Purpose of the Study:
- To mathematically analyze the storage effect's contribution to competing natural populations.
- To investigate the coexistence mechanisms of two Daphnia species in Oneida Lake.
Main Methods:
- Mathematical analysis of population dynamics.
- Analysis of 30 years of zooplankton data from Oneida Lake.
- Calculation of long-term population growth rates with and without environmental variation.
Main Results:
- A negative correlation was observed between Daphnia galeata mendotae and Daphnia pulicaria densities.
- Both species possess long-lived eggs, creating overlapping generations.
- Environmental variation and dormancy (storage effect) are essential for D. galeata mendotae persistence, while D. pulicaria relies on consistent recruitment.
Conclusions:
- The storage effect is a critical factor enabling the coexistence of competing Daphnia species.
- Environmental variability and prolonged dormancy are key to maintaining biodiversity in fluctuating ecosystems.
- Daphnia galeata mendotae persistence is contingent on the storage effect, unlike Daphnia pulicaria.