Stable Isotopes of Carbon and Nitrogen in Female Qamanirjuaq Caribou ( <i>Rangifer tarandus groenlandicus</i> ) Antlers in Relation to Diet and Physiology
Bibliographic record
Abstract
ABSTRACT Populations of Arctic barren‐ground caribou ( Rangifer tarandus groenlandicus ) have fluctuated over the past few decades but are currently in decline. To support conservation efforts of caribou, it is integral to develop both historical and modern datasets; these datasets allow us to understand how caribou have adapted to past climatic shifts and may respond to future change. Caribou are the only extant species in which both males and females grow antlers each year, providing unique sex‐specific isotope datasets. Isotopic study of antlers is proving to be a source of annualized data on caribou diet and migration, but uncertainty remains in the magnitude and drivers of isotopic changes across individual antlers. Nitrogen (δ 15 N Col ) in male antlers from the Qamanirjuaq herd has been shown to increase along the main antler beam aligned with known shifts in seasonal diet and/or the increased energy requirements. We examined 19 female antlers from the same population to compare δ 13 C Col and δ 15 N Col between sexes and among varying reproductive statuses. Female antlers were found to be ~0.4‰ lower in δ 13 C Col at the bases of their antlers compared to males. In both sexes, caribou antler collagen varied in δ 13 C Col among individuals by ~2‰ (−20.0‰ to −18.1‰) and in δ 15 N col by ~5‰ (+2.3‰ to +7.3‰). We conclude that δ 13 C Col differences between sexes are the result of differing diets during the onset of antler formation, corresponding to the different seasons that females and males initiate antler growth. Despite dietary differences, both males and females increased in δ 15 N Col along the antler beam by approximately 1‰–1.5‰. Increases in δ 15 N Col along the antler beam coincide with the increased physiological stress and material demands during antler development. Antler tissue remains a promising resource for studying both short‐ and long‐term changes in male and female caribou ecology.
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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 | 0.000 |
| 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".