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Record W1892036403 · doi:10.1139/cjfas-2013-0594

Mediation functions in Ecopath with Ecosim: handle with care

2014· article· en· W1892036403 on OpenAlexvenueno aff
Chris J. Harvey

Bibliographic record

VenueCanadian Journal of Fisheries and Aquatic Sciences · 2014
Typearticle
Languageen
FieldEnvironmental Science
TopicMarine and fisheries research
Canadian institutionsnot available
Fundersnot available
KeywordsSigmoid functionBiomass (ecology)MediationEnvironmental scienceJuvenileZostera marinaEcologyAbundance (ecology)HabitatFisheryGeographyBiologyComputer scienceSeagrassSociology

Abstract

fetched live from OpenAlex

Ecosystem models are important tools for addressing complex issues such as the role of habitat in marine resource management. The Ecopath with Ecosim (EwE) software can represent several ecological processes via mediation functions, where the abundance of one group influences trophic interactions between two other groups. I ran a series of temporal simulations in EwE, in which eelgrass (Zostera marina) was refuge habitat for juvenile Pacific salmon (Oncorhynchus spp.), and the abundance of eelgrass mediated (reduced) the vulnerability of juvenile salmon to their predators. I compared the effects of eelgrass on salmon biomass across three shapes of mediation curve (linear, hyperbolic, sigmoid) and six different initial states along each curve. Salmon responded strongest to sigmoid mediation and least to hyperbolic mediation. Salmon responses were sensitive to initial conditions, particularly along sigmoid curves. As the lower limit of the mediation curve (Mmin) approached 0, model results became nonintuitive, particularly for sigmoid curves. Because these functions are difficult to quantify or scale from empirical or experimental studies, modelers must carefully account for uncertainty when using mediation relationships in EwE. Hyperbolic mediation curves may be the most conservative when empirical or theoretical knowledge is unavailable.

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 machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.004
metaresearch head score (Gemma)0.013
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.058
Threshold uncertainty score0.196

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0040.013
Meta-epidemiology (narrow)0.0020.001
Meta-epidemiology (broad)0.0010.002
Bibliometrics0.0010.001
Science and technology studies0.0010.001
Scholarly communication0.0020.003
Open science0.0040.004
Research integrity0.0010.003
Insufficient payload (model declined to judge)0.0580.009

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 head0.010
GPT teacher head0.195
Teacher spread0.185 · 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; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
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

Citations19
Published2014
Admission routes1
Has abstractyes

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