An experimental study: effects of boulder placement on hydraulic metrics of instream habitat complexity
Bibliographic record
Abstract
Boulder placement is a common method to restore degraded instream habitats by enhancing habitat complexity. This experimental study is the foremost attempt to systematically investigate the influence of rock-ramp boulder placement with varying boulder concentration and flow rate on habitat hydraulic complexity metrics, including the kinetic energy gradient and modified recirculation metrics. By adding boulders to a reach, the modified recirculation metric increased by one order of magnitude for all boulder concentrations. Based on the studied metrics, boulder placement with the highest boulder concentration (λ = 8.3%) resulted in the greatest habitat hydraulic complexity. A set of relationships of moderate strength were proposed to predict the metrics in reaches with boulders by having information about only boulder concentration, habitat characteristic size, and reach-averaged flow characteristics. Based on the available data from the literature, boulder placement especially at higher concentrations may provide suitable habitats for several riverine fish species. Further studies are needed to establish a reliable linkage between the metrics and instream species, to test a wider variety of parameters for verifying and improving the range of applicability of the proposed relationships, and to find the structural configuration at which the habitat complexity is maximized or optimized for a certain species.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".