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Record W1860217797 · doi:10.1890/14-0126.1

Detecting cyclicity in ecological time series

2015· article· en· W1860217797 on OpenAlexaff
Stilianos Louca, Michael Doebeli

Bibliographic record

VenueEcology · 2015
Typearticle
Languageen
FieldEnvironmental Science
TopicEcosystem dynamics and resilience
Canadian institutionsUniversity of British Columbia
Fundersnot available
KeywordsNull hypothesisNull (SQL)White noisePopulation cycleNull modelSeries (stratigraphy)PopulationNoise (video)UncorrelatedEcologyStatistical hypothesis testingStatistical physicsStatisticsBiological systemMathematicsEconometricsBiologyComputer scienceArtificial intelligenceData miningPhysics

Abstract

fetched live from OpenAlex

Cyclic population dynamics are of central interest in ecology. Reliably identifying and quantifying the cyclicity of populations is valuable for the understanding of regulatory mechanisms and their variability across spatiotemporal scales. Cyclicity can be detected using periodogram analysis of time series. The statistical significance of periodogram peaks is commonly evaluated against the null hypothesis of uncorrelated fluctuations, also known as white noise. Here, we show that this null hypothesis is inadequate for cycle detection in ecosystems with non‐negligible correlation times. As an alternative null hypothesis we propose the so‐called Ornstein‐Uhlenbeck state‐space (OUSS) model, which generalizes white noise to allow for temporal correlations. We justify its use on mechanistic principles and demonstrate its advantages using numerical simulations of simple population models. We show that merely contrasting cyclicity against white noise greatly increases the false cycle detection rate and can lead to wrong conclusions even for simple systems. A comparative statistical analysis of the Global Population Dynamics Database using both null hypotheses suggests that a significant number of populations might have been misinterpreted as cyclic in the past. Our proposed methods for cycle detection are available as an R package (peacots).

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesInsufficient payload (model declined to judge)
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.035
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.002

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.

Opus teacher head0.008
GPT teacher head0.212
Teacher spread0.205 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; both teacher heads agree on what is shown here.

Study designObservational
Domainnot available
GenreEmpirical

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".

Quick stats

Citations18
Published2015
Admission routes1
Has abstractyes

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