Black spruce regeneration at the treeline ecotone: synergistic impacts of climate change and caribou activityThis article is a contribution to the series Tree recruitment, growth, and distribution at the circumpolar forest–tundra transition.
Bibliographic record
Abstract
Tree regeneration at treeline is often inhibited by harsh climatic conditions and ecological constraints such as the presence of a continuous lichen cover. The objective of this study was to verify if recent climate warming and increased caribou (Rangifer tarandus L.) activity, which destroys the lichen cover, could act synergistically to increase black spruce (Picea mariana (Mill.) B.S.P.) regeneration. We collected cones produced in 2006–2007 to compare seed viability with data from 1989 to 1995. We conducted experimental plantations (field and controlled conditions) to determine if germination and seedling emergence were higher in disturbed environments where mineral soil was exposed. We sampled naturally established seedlings to evaluate the relationship between the year of establishment and caribou activity and to compare growth in disturbed and undisturbed environments. We found that seed viability was significantly higher in 2006–2007 compared with 1989–1995. The number of germinated seeds per cone increased by a factor >1000. Germination and seedling establishment were higher in the disturbed environment (mineral soil). Finally, although seedling establishment in areas with continuous lichen cover was rather constant over the last 50 years, 73.5% of the seedlings recorded on bare mineral soil became established in the years following high caribou activity. Our results suggest that climate warming and caribou activity are likely to act synergistically to promote black spruce regeneration at treeline.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".