Conservation genetics of Hill’s thistle (<i>Cirsium hillii</i>)
Bibliographic record
Abstract
Populations at the edges of their geographical ranges are often characterized by reduced genetic diversity and increased genetic differentiation. These patterns may be exacerbated by specialized associations between plants and uncommon habitats. Together, reduced diversity and increased subdivision may increase the risk of population extirpation, an issue that is particularly important for plants classified as rare or threatened. Hill’s thistle (Cirsium hillii (Canby) Fernald), is a perennial herb endemic to the Great Lakes region and is considered threatened in Canada where its northernmost distribution occurs. We used microsatellite markers to genotype plants from 11 populations of Hill’s thistle that span the range of the species distribution within Canada. These data were used to investigate levels of genetic diversity within populations and genetic differentiation between populations, and to evaluate associations between patterns of genetic variation and those expected under ongoing habitat loss. Genetic differentiation among populations was low, although significant pairwise FST values, along with the presence of private alleles in most populations, was consistent with moderate to low gene flow. Nevertheless, in comparison with a congeneric rare species (Cirsium pitcheri) that occurs in the same geographical region in Canada, genetic diversity within most populations was high, and we suggest that this is at least partially attributable to this species’ combination of sexual and clonal reproduction. Despite high levels of genetic diversity, Hill’s thistle should probably remain a designated species at risk because of ongoing habitat loss; however, our data suggest that Hill’s thistle is unlikely to suffer from reduced genetic diversity in the foreseeable future.
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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 | 0.000 | 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) | 0.001 | 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".