Sexual reproduction of Japanese knotweed (<i>Fallopia japonica</i> s.l.) at its northern distribution limit: New evidence of the effect of climate warming on an invasive species
Bibliographic record
Abstract
PREMISE OF THE STUDY: In response to climate warming, plant species may shift their distribution northward, but such a process is slow and hard to detect. Alternatively, phenological changes (earlier flowering) are expected as first adaptations for populations located near their distribution limit. That could be the case for the invasive Japanese knotweed (Fallopia japonica s.l., including the hybrid Bohemian knotweed F. ×bohemica). We hypothesized that climate warming now allows the species to produce viable seeds in the northernmost populations. METHODS: Seeds were collected along a 550 km long transect in Quebec, Canada, and tested for germination. The genetic diversity of a population was determined using polymorphic microsatellite markers to verify whether the species is actually producing new individuals through sexual reproduction. KEY RESULTS: Japanese knotweed produces, in Quebec, a large number of seeds with a high germination rate (up to 93%). The geographical limit for viable seed production in North America has been extended to Quebec City, about 500 km north of the formerly reported limit. Bohemian knotweeds are genetically diverse, while true Japanese knotweeds all share a common multilocus genotype. This suggests that Bohemian knotweed stands mostly arose from seed, while true Japanese knotweeds result only from the propagation of rhizome or stem fragments. CONCLUSIONS: The effect of climate change is already palpable on the phenology of invasive plant species at their northern distribution limit. Bohemian knotweed, which until recently was rare in Quebec, could rapidly spread in the near future with the help of an additional diaspore type (seeds).
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".