Reconstructing spruce budworm outbreak severity: a comparison of paleoecological and tree-ring signals
Bibliographic record
Abstract
Applying a centennial or millennial perspective to disturbance regimes permits an understanding of how these events have varied in the past in relation to climate change. Correctly interpreting this variability is crucial when preparing sustainable forest management practices for future warming. The eastern spruce budworm (Lepidoptera) is the most important biotic disturbance in the eastern Canadian boreal forest. Adult moths are covered by chitinous scales, and lepidopteran scale records in lake sediments have been analyzed to reconstruct Holocene spruce budworm populations. However, the magnitude of these scale accumulations has yet to be calibrated using an independent proxy. Here, we determine whether the impacts of spruce budworm defoliation are recorded by both sedimentary lepidopteran scale accumulations and tree-ring widths. Agreement between proxies was found at five of nine sites and strongest between the proportion of affected trees and scale accumulations while agreement in signal synchronicity was found at six of nine sites and strongest when comparing scale accumulations to a growth suppression index. A species-based composite chronology relying on white spruce produced the clearest outbreak record for both proxy records. Peak scale accumulations correlated well with smaller tree-ring widths, demonstrating that larger scale accumulations correspond to more severe defoliation events. Therefore, lepidopteran scales provide reliable records of spruce budworm abundance serving as a proxy record ameliorating our understanding of how budworm impacts have fluctuated at centennial and millennial time scales in the context of past climate 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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 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".