Unimodal relationship between adult and recruit density in barnacle populations
Bibliographic record
Abstract
Recruitment is a key demographic step for population persistence. This paper focuses on understanding barnacle ( Semibalanus balanoides ) recruitment. In rocky intertidal habitats from the Gulf of St. Lawrence coast of Nova Scotia (Canada), winter ice scour is common. At the onset of intertidal barnacle recruitment in the spring, mostly only adult barnacles and bare substrate are visible at high elevations on the shore. We conducted a multiannual study to investigate if small-scale barnacle recruitment could be predicted from the density of pre-existing adult barnacles. In a year that exhibited a wide adult density range (ca. 0–130 individuals dm -2 ), the relationship between adult density and recruit density (referred to the available area for recruitment, which excluded adult barnacles) was unimodal. In years that exhibited a lower adult density range (ca. 0–40/50 individuals dm -2 ), the relationship between adult and recruit density was positive but simply resembling the lower half of the unimodal relationship. Overall, adult barnacle density was able to explain 26–40 % of the observed variation in recruit density. The unimodal adult–recruit relationship is consistent with previously documented intraspecific interactions. Between low and intermediate adult densities, the positive nature of the relationship relates to the ability of adult barnacles to attract settlement-seeking larvae, likely enhancing local population persistence where it is most needed. Between intermediate and high adult densities, where population persistence may be less compromised and the abundant adults may be detrimental to recruit growth, the negative nature of the relationship suggests that larvae are stimulated to settle elsewhere. This unimodal pattern may be particularly common on shores with moderate rates of larval supply to the shore, as high larval supply rates may swamp the coast with settlers, decoupling recruit density from local adult abundance.
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".