An experimental test of the effects of dispersal and the paradox of enrichment on metapopulation persistence
Bibliographic record
Abstract
Many species exhibit high‐amplitude, extinction‐prone cycles, for instance due to resource enrichment (called the paradox of enrichment). How do such species manage to persist? One possibility is metapopulation dynamics, but it is unclear if these can mitigate the paradox of enrichment. The paradox of enrichment might increase local population extinction rates, and might also increase the spatial synchrony of population fluctuations because population cycles are easily synchronized by even low rates of dispersal. Spatially‐synchronous population fluctuations would leave no scope for rescue effects, and spatially‐synchronous local extinctions would leave no source for recolonization. We conducted a protist microcosm experiment to test how dispersal and enrichment affect the persistence of predator–prey metapopulations by altering spatial synchrony. We assembled 54, 4‐patch metapopulations of the protist predator Euplotes patella and its protist prey Tetrahymena pyriformis . Each metapopulation experienced one of nine dispersal rates, crossed with one of six enrichment levels. We tested the effects of enrichment and dispersal on predator–prey cycle amplitude, predator population extinction risk, spatial synchrony of predator population fluctuations, and predator metapopulation persistence time. Enrichment increased predator–prey cycle amplitude but had no detectable effect on population extinction risk. Dispersal had no effect on predator–prey cycle amplitude. Spatial synchrony increased with enrichment and dispersal. Metapopulation persistence decreased with enrichment and spatial synchrony. We conclude that increasing enrichment reduced metapopulation persistence primarily by increasing spatial synchrony of local extinctions, rather than by increasing their frequency. These results highlight the importance of synchrony‐preventing mechanisms for metapopulation persistence.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".