Factors driving switches in the primary producer communities of shallow lakes of the Boreal Plains, Alberta, Canada
Bibliographic record
Abstract
The mechanisms that contribute to the frequent switching of primary producer communities in shallow lakes on the Boreal Plains of Alberta, Canada were explored. The lakes tend to be clear and macrophyte-rich (61% of lakes) or turbid and phytoplankton-rich (30% of lakes). The study is based on surveys of twenty-three lakes on the Boreal Plains, Alberta, Canada monitored from 2001 to 2007. I examined the effect of annual fluctuations in precipitation on the limnological conditions of the study lakes and the primary producer communities. Drought concentrated nutrients, phytoplankton biomass and turbidity, decreasing macrophytes cover and promoting a phytoplankton-rich regime. Macrophyte abundance was better predicted by lake depth. During the study SAV cover increased with lake depth and was significantly higher in 2007 following three years of high water levels. Precipitation-induced switches occur because the lakes are small, isolated and the water budget is dominated by precipitation inputs and evaporative outputs with little surface or groundwater fluxes. The lake and landscape factors affecting the persistence of the macrophyte-rich regime and phytoplankton-rich regime were assessed. The macrophyte-rich regime was more persistent in shallow lakes (max. depth < 112 cm) with high macroinvertebrate predator biomass (> 580 µg L-1) and low TP concentration (< 58 µg L-1) (variance explained = 0.66). Lakes with high Daphnia dominance (> 61% of the Cladocera community) and higher TP concentration (> 67 µg L-1) were associated with a more persistent phytoplankton-rich regime (variance explained = 0.50). I examined the importance of food web structure in maintaining the alternative regimes. Food web structure appears important in maintaining the resilience of the macrophyte-rich regime in fishless lakes on the Boreal Plains. The macrophyte-rich regime is reinforced (stabilized) by top-down control of phytoplankton and periphyton by macroinvertebrates and zooplankton. In contrast, food web effects appear weak or absent in the phytoplankton-rich regime.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 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".