Lepidopteran scales in lake sediments as a reliable proxy for spruce budworm outbreak events in the boreal forest of Eastern Canada
Bibliographic record
Abstract
Characterizing disturbance regimes over long time scales is paramount for describing and identifying their variability. The most important biotic disturbance in the eastern Canadian boreal forest is the defoliation caused by the eastern spruce budworm, a moth of the insect order Lepidoptera. Lepidopteran scales have recently been used to reconstruct spruce budworm population fluctuations throughout the Holocene. However, this novel proxy has yet to be compared to an independent proxy. This study aimed to determine whether lepidopteran scales found in the surface sediments of boreal lakes tracked large spruce budworm populations, that is, outbreaks, using yearly aerial surveys (1967–present) of spruce budworm defoliation as an independent proxy. Scales were extracted (1 cm resolution) from the top 20 cm of 210 Pb-dated sediment cores recovered from nine lakes. To identify significant abundance peaks of scales in the time series, we removed background noise using a modified version of CharAnalysis. A 100-year smoothing window width combined with a 60th percentile threshold yielded the highest true positive and true negative occurrences, and the lowest false positive and false negative occurrences, with values of 0.69 and 0.70 for Cohen’s Kappa and Matthews correlation coefficient, respectively. Our findings demonstrate that lepidopteran scales are a suitable proxy for identifying spruce budworm outbreaks in the sediment record enabling the reconstruction of budworm and other lepidopteran species outbreak dynamics at millennial timescales.
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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 | 0.001 | 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 | 0.000 |
| 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".