Holocene Treeline and Climate Change in the Subalpine Zone near Stoyoma Mountain, Cascade Mountains, Southwestern British Columbia, Canada
Bibliographic record
Abstract
Multiproxy paleoecological investigation of a small lake in the high subalpine zone near Stoyoma Mountain, northern Cascade Mountains of British Columbia, reveals significant change in vegetation, limnic conditions, and inferred climate throughout the Holocene (last 10,000 radiocarbon years). Three zones of distinct pollen, plant macrofossil, and chironomid assemblages are apparent in the sediment core from 3M Pond (informal name). A dry, sparsely vegetated spruce parkland and a warm-adapted chironomid community existed in and around the study sites in the early Holocene (ca. 10,000 to 7000 14C yr BP). Between 7000 and 3500 14C yr BP, Engelmann spruce–subalpine fir forest conditions established and then declined around 3M Pond leading to modern subalpine parkland conditions from 3500 14C yr BP to present. Chironomid communities at 3M Pond between 7000 and 3500 14C yr BP are indicative of warmer waters than present, but show a transition to modern assemblages. Three climatic regimes are identified near Stoyoma Mountain: (1) the early Holocene xerothermic period (10,000 to 7000 14C yr BP, (2) a period of climatic transition in the mid-Holocene (7000 to 3500 14C yr BP), and (3) cool, modern neoglacial conditions (after 3500 14C yr BP). These findings confirm vegetation and inferred climate changes identified at Cabin Lake, British Columbia (a nearby lake in the subalpine forest). Changes in treeline position, plant communities, chironomid communities, and inferred climate are nearly synchronous and validate the multiproxy approach for paleoecological reconstruction. Chironomid-based paleotemperature reconstructions confirm earlier evidence that the early Holocene was significantly warmer than present, with estimated summer water surface temperatures up to 4°C higher than today.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".