Beavers as ecosystem engineers – a review of their positive and negative effects
Bibliographic record
Abstract
The paper reviews the environmental activity of beavers ( Castor fiber L. and Castor canadensis L.) and their impact on different aspects of the environment. Beavers inhabit almost all climatic zones but are most abundant in Russia, USA, and Canada. Beavers' ecosystem engineering activities include building dams and creating ponds. The dams provoke hydrological alteration, soil overwetting, changes in local micro- and nanorelief. The water stagnation in beaver ponds below dams results in lack of oxygen, a high carbon concentration, and the death of many aquatic organisms. The flooding water above the dam causes vegetation death due to overwetting and at the same time a rise in the biodiversity of water organisms. This paper includes original data gathered by Tomsk State University on lack of oxygen and subsequent fish death in dammed ponds. All environmental changes are cumulative and have strong contextual dependence. The beavers' environmental activity has positive and negative consequences.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".