Multiproxy lake sediment records at the northern and southern boundaries of the Aspen Parkland region of Manitoba, Canada
Bibliographic record
Abstract
Aspen parkland in central Canada may change substantially with increased warming and aridity as prairies replace forests, fire return intervals decrease and lake levels decline. We examined the relationships among vegetation, climate, fire and lake-ecosystem properties using lake sediment cores from the current northern and southern boundaries of the aspen parkland in southwestern Manitoba. We analyzed pollen, charcoal, sediment magnetics, biogenic silica, phosphorus, grain size and LOI, and dated the cores using 210 Pb and 14 C (AMS, calibrated). The Jones Lake record, from the southern edge of the parkland, began considerably earlier (~11 000 cal. BP) than the Mallard Pond record at the northern edge (~8600 cal. BP). These sites were characterized as prairie communities with low fire severity and relatively low lake productivity during the warm, dry period from 9000 to 6000 cal. BP. Beginning around 6500 cal. BP at Jones Lake and 3400 cal. BP at Mallard Pond, conditions appeared to get wetter as indicated by arboreal pollen percentage increases from ~30% to 40— 60%, concurrent with a rise in charcoal and proxies for lake productivity (biogenic silica and percent organic phosphorus). Similar to previous studies along the prairie—forest border, we found that charcoal increased during warmer, wetter periods with increased forest cover and fuel loading rather than during warmer, drier periods of prairie dominance. Our results underscore the importance of regional changes in moisture, and its effects on lake levels and forest biomass, as a dominant control of the aspen parkland dynamics.
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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 | 0.000 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".