Community consequences of indirect interactions between waterfowl and tiger salamanders in prairie potholes
Bibliographic record
Abstract
Waterfowl are attracted to prairie wetlands or "potholes" to satisfy nutritional demands for reproduction and brood rearing during the breeding season. Although most potholes in the Minnedosa, Manitoba, area are devoid of native fish populations, many are occupied by tiger salamanders ('Ambystoma tigrinum'). To test the hypotheses that waterfowl influence pothole community structure and indirectly interact with tiger salamanders, I completed a series of observational and manipulative studies. I determined that tiger salamander occupancy rates of potholes were high (75-80%) but densities ranged widely. Trophic structure varied according to tiger salamander density but greater contrasts in invertebrate abundance and phytoplankton standing crop were obtained between high and low densities rather than simple presence or absence. I interpreted positive relationships between tiger salamander density and phytoplankton standing crop as an indirect effect of nutrient recycling and transfer by tiger salamanders rather than direct consumer-resource interactions between trophic levels. I compared dietary and pothole overlap between ducks (Subfamily Anatinae) and tiger salamanders to estimate the potential for indirect interactions. I found that dabbling ducks had greater overlap in diet with tiger salamanders than diving ducks, but that diving ducks overlapped more among potholes with tiger salamanders than dabbling ducks. Using exclosures, I determined that invertebrate populations increased and phytoplankton standing crop decreased in the absence of duck, grebe and coot predation. However, the effects of waterfowl exclusion on pothole trophic structure were obscured by the presence of tiger salamanders, especially at high densities. This indirect interaction is an example of compensatory predation and it indicates that either waterfowl or tiger salamanders can control pothole trophic structure. Subsequently, I manipulated tiger salamander densities to test for the effects of food web variation on waterfowl. Within potholes I found that waterfowl preferentially foraged where tiger salamander densities were lower and among potholes I found that American coot ('Fulica americana') chick growth rates were decreased in the presence of tiger salamanders. These results indicate that waterfowl and tiger salamanders exert trophic control on prairie potholes by competing for shared prey and that community studies of prairie potholes are incomplete without the inclusion of tiger salamanders.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".