Late Holocene Climate of the James Bay Area, Quebec, Canada, Reconstructed Using Fossil Beetles
Bibliographic record
Abstract
We used fossil beetles recovered from three peatlands of the James Bay area (Radisson, northern Quebec, Canada), and the mutual climatic range (MCR) method, to produce a quantitative reconstruction of summer temperatures during the last 5000 yr. Our main objective was to test the hypothesis that a significant climatic cooling episode occurred during the late Holocene epoch, leading to the opening up of the boreal forest, and to the progressive replacement of black spruce (Picea mariana) forests by jack pine (Pinus banksiana) stands. Beetle assemblages in the Radisson area were very stable during the late Holocene epoch. We used a total of 22 beetle species to conduct the MCR analyses. Reconstructed mean July temperatures ranged from 14.5 to 17.5°C, which is close to the present-day (A.D. 1977–1996) temperature range found in the Radisson area. The general stability of beetle assemblages, and the MCR analyses, suggest that there was no major change in July temperatures during the last 5000 yr in the Radisson area. This study provides no evidence that the progressive replacement of black spruce forests by jack pine stands in the Radisson area during the last 2700 yr can be explained by a longterm climatic cooling episode affecting the postfire regeneration potential of trees. Consequently, an alternative hypothesis (more frequent fires favoring jack pine) should be seriously considered to explain the late Holocene changes in the forest environment of the Radisson area.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".