Effects of dietary selenium on reproduction and body mass of captive lesser scaup
Bibliographic record
Abstract
The continental population of scaup has declined over the last three decades to levels that remain well below conservation goals. One proposed hypothesis for this decline is that increasing exposure to contaminants has led to decreased fitness in scaup, and selenium (Se) has been identified as a contaminant of concern. We conducted an experiment with captive scaup to simulate late spring migration exposure to environmentally relevant doses of dietary Se (control [<1 microg/g total Se], and 7.5 microg/g and 15 microg/g Se as selenomethionine) for 30 d, after which excess Se was removed from the diets prior to laying. Overall, we found no treatment effect on body mass, breeding probability, or clutch initiation dates. Egg Se concentrations of the 15 microg/g and 7.5 microg/g groups decreased rapidly after Se-supplemented diets were removed and within 12 and 8 d post treatment, respectively, were below the suggested egg teratogenicity threshold of 9 microg/g (dry wt). We found no significant intraclutch variation in egg Se deposition. Blood Se concentrations differed between groups in proportion to dose, with a half-life of 16 and 22 d for females when removed from the 15 and 7.5 microg/g treatments, respectively. Our findings suggest that exposure to dietary Se concentrations representative of spring-staging environments is insufficient to adversely affect body mass or reproduction in scaup that subsequently migrate to uncontaminated breeding areas (e.g., in prairie-parklands and boreal forest). Further studies of Se effects on scaup should focus on wintering birds in contaminated habitats.
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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 | 0.001 |
| 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 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".