Late Quaternary dynamics of tundra and forest vegetation in the southern Niagara Escarpment, Canada
Bibliographic record
Abstract
• Here, paleoecological studies from southern Ontario, Canada, are detailed to reconstruct vegetation history of the last 13 000 14 C year, with emphasis on late-glacial treeless vegetation. • Two sites (Crawford Lake and Twiss Marl Pond) were investigated using combined pollen and plant–macrofossil stratigraphic data. Comparison of multivariate analysis of pollen data with climate variations inferred independently from oxygen isotopes at the same site facilitated systematic evaluations of climate–vegetation interactions during different stages of vegetation development. • Pollen results show a distinctive successional change from Alnus – Dryas –Cyperaceae sparse tundra or periglacial desert to Salix – Juniperus –Cyperaceae dense tundra, with abundant arctic/alpine plant macrofossils, during the first few centuries after ice retreat. The area around the two sites was then dominated by Picea ( c. 12 000–10 000 14 C BP). Vegetation shifts, summarized by log-contrast principal component analysis of the pollen record, indicated a lagged response of forests to deglacial climate warming. The major vegetation shift at c. 7500 14 C BP from coniferous Pinus -dominated to mixed forests probably corresponded to a major shift from deglacial to full postglacial climates. Vegetation during the mid- and late Holocene responded more directly to natural (drought-triggered pathogen-induced Tsuga decline) and human disturbances (aboriginal and EuroCanadian settlements). • This study demonstrates that bedrock basins most faithfully recorded the earliest vegetation change because they usually experienced a short delay in lake formation after ice retreat.
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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 | 0.002 | 0.003 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".