Exotic earthworm invasion increases soil carbon and nitrogen in an old-growth forest in southern Quebec
Bibliographic record
Abstract
To test whether invasion of exotic earthworms affects soil carbon (C) and nitrogen (N), we sampled the litter and upper mineral soil (to 30 cm) at a series of sites varying in their earthworm populations in an old-growth beechmaple forest at Mont St. Hilaire, southern Quebec. We measured earthworm abundance and biomass using hand-sorting and chemical extraction (allyl isothiocyanate) methods. They gave similar results, though there was evidence of size and species-specific biases. Abundance and biomass of the earthworms ranged from <10 to >100 earthworms·m2 and from <10 to 125 g·m2, respectively, and were correlated with distance from a nearby lake (negatively) and soil pH (positively). The presence of earthworms was associated with a decrease in the mass and thickness and an increase in the C/N quotient of the litter layer. There were no significant changes in C and N mass of the mineral soil between 0 and 10 cm, but the underlying layers (1020 and 2030 cm) in sites with >10 earthworms·m2 showed significantly (p < 0.05) greater concentrations and masses of both C and N than did sites with <10 earthworms·m2. The overall profile (litter plus soil to 30 cm) average C was 13.7 and 10.1 kg·m2 with and without earthworms, respectively, and the equivalent figures for N were 1.01 and 0.68 kg·m2. These results demonstrate that invasion of earthworms into deciduous forests affects both the litter and mineral soil, and sampling to a depth of 30 cm suggests that earthworm invasion (from <10 to >10 earthworms·m2) may increase overall C and N.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".