A century of high elevation ecosystem change in the Canadian Rocky Mountains
Bibliographic record
Abstract
Mountain ecosystems serve as sentinels of change, and those in the Canadian Rocky Mountains have undergone a pronounced shift over the past century. We present quantitative analyses of 81 high-resolution image pairs of systematic historic surveys and repeat photographs of Canadian Rocky Mountain habitats, measuring treeline advance, changes in tree density, and shifts in growth form from krummholz to trees. With a time-lapse of 68 to 125 years (mean 93.5 years) between image pairs, these photographs contain novel information about long-term ecological change across broad spatial scales. In the 197 linear km of mountain habitat over 5 degrees of latitude examined, we found evidence of treeline advance at 90/104 sites, increases in tree density at 93/104 sites, and many sites (79/95) showing detectable changes in the growth form of trees from krummholz to erect tree form. Using generalized linear mixed models, we found that treeline at higher altitudes and further north had a greater probability of advancing while regional climate factors in our model did not significantly explain our results. Historic references, such as those documented here, are invaluable for providing conservation targets and for contextualizing disturbance and broad scale ecosystem change.
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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 | 0.001 | 0.002 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".