Invertivory by northern pike (<i>Esox lucius</i>) structures communities of littoral macroinvertebrates in small boreal lakes
Bibliographic record
Abstract
Recent comparative studies suggest that macroinvertebrates in small Boreal Plains lakes respond to large fluctuations in fish densities caused by winterkill and subsequent recovery even when such fluctuations involve the normally piscivorous northern pike (Esox lucius). We introduced pike into a boreal lake made fishless by a past winterkill to isolate experimentally the effects of pike on littoral macroinvertebrates. We compared postmanipulation macroinvertebrate data from the experimental lake (EXP) to premanipulation data from the same lake, to parallel data from 2 unmanipulated reference lakes (R1 and R2) containing pike, and to data from mesocosms within EXP. Pike in all 3 lakes preyed heavily upon macroinvertebrates; diets consisted predominantly of the amphipod Gammarus lacustris in R1 and R2 and erpobdellid leeches in EXP. Principal components analysis (PCA) of macroinvertebrate communities distinguished between systems with and without fish and detected a shift in the macroinvertebrate community of EXP and predator-exposed control mesocosms away from large conspicuous taxa (e.g., odonates, coleopterans, and leeches) toward less-conspicuous taxa such as dipterans and trichopterans following manipulation. Responses of individual taxa were generally in agreement with PCA; erpobdellid leeches and odonates showed consistent negative responses to pike. Our study provides experimental evidence at the whole-lake scale that northern pike can affect littoral macroinvertebrates in small boreal lakes, and demonstrates the sensitivity that littoral food webs in these systems can have to changes in the density of fish.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 teacher head, 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".