Genetic erosion and population resilience in <i>Daphnia longispina</i> O.F. Müller under simulated predation and metal pressures
Bibliographic record
Abstract
This study investigated the effects of nonselective predation (culling) and metal toxicity on the genetic diversity of laboratory populations of the cladoceran Daphnia longispina. Populations, comprising five clones differing in their sensitivity to lethal concentrations of a metal-rich mine drainage effluent, were subjected to all possible combinations of three levels (absent, weak, and strong) of each stressor. Observed population densities were compared to those expected from a life history experiment, and clone frequencies were determined by allozyme profiling. Culling did not affect population density, although clonal diversity was higher than the control. Populations stressed by mine drainage recovered to their initial densities within 12 days, though the most sensitive genotypes disappeared under both weak and strong metal stress levels. Because the surviving resistant clones were shown to be the most sensitive ones to other chemicals (Cd and H+), it is suggested that successive inputs of partially lethal concentrations of different chemicals can lead to the disappearance of the population, even if the time between inputs is large enough to allow density recovery. These results suggest that changes in abundance are not enough to evaluate ecological effects of chemicals on the environment and information on co-tolerance and multiple tolerance within populations is highly valuable to prevent their extinction. Moreover, populations exposed to low levels of both stressors showed clonal diversity levels identical to controls, highlighting the importance of low level effects of nonselective stressors in the maintenance of high clonal diversity levels in Daphnia populations, and thus further supporting the intermediate disturbance hypothesis.
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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 | 0.000 | 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 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".