Suspended Sediment in Silvester Creek and its Potential Effects on the Westslope Cutthroat Trout Population
Bibliographic record
Abstract
Total suspended sediment (TSS) can have extensive negative effects on fishes within streams, ranging from mild avoidance by individuals to complete mortality of populations. Severity of effects depends on the concentration and duration of exposure, and the life-history stage of the fish, with eggs and larvae being the most sensitive. I surveyed spring suspended sediment concentrations and duration in Silvester Creek, a small tributary of the Elbow River in the Rocky Mountain foothills of Alberta, to evaluate potential effects of TSS on a rare genetically- pure, apparently native population of westslope cutthroat trout, a spring-spawning species recognized by the federal Species at Risk Act and provincial regulations under the Wildlife Actas Threatened in the province. The Silvester Creek basin lies entirely within a land-use zone permitting effectively uncontrolled use by recreational off-highway vehicles (OHVs) in combination with livestock grazing, logging, and gasfield development. Linear disturbance density is 2.5 km/km2 overall, and reaches 4.8 km/km2 in some parts of the basin, delivering fine sediment at 41 points, including 2 natural sources, from the extreme headwaters to near the mouth. Three sampling regimes were used: an intensive, day-long analysis at 4 principal stations in a long meadow reach; a before-after-thunderstorm analysis at 12 sites; and daily sampling at 5 sites on 6 consecutive days that incorporated a weekend, weekdays, dry weather and rainy days. Control samples from sites above the influence of roads and trails within the Silvester Creek basin were low in TSS, not exceeding 1.2 mg/L, and usually equalling or approaching zero mg/L. In contrast, TSS concentrations downstream from known or expected sediment sources were elevated relative to the controls, commonly averaging 20-40 mg/L during prolonged rainy weather, while individual samples sometimes were much higher (up to 154 mg/L) after an intense thunderstorm, or 179 mg/L after one or more dry-weather OHV crossings. During dry weather TSS remained as low as 5-7 mg/L at 2 stations, but averaged around 20-30 mg/L at 2 others. Durations were sufficient, even for the lowest dry-weather TSS loads, to cause mostly minor to moderate sublethal effects to juvenile and adult trout, but paralethal to lethal effects on eggs and larvae during the ongoing spawning and egg incubation period. Considering the survey results as a reasonable sample applying to typical spring periods in this basin, I estimated that eggs and larvae typically would sustain at least 40-60% mortality from prolonged TSS exposure, and that adult trout typically would experience moderate physiological stress, while juveniles would typically suffer major physiological stress, reduced feeding rate and success, as well as poor condition. After considering previously-reported population data and literature on the requirements of conserving small populations, I concluded that the Silvester Creek population of westslope cutthroat trout is at unnecessary risk due to the effects of prolonged exposure to TSS from the extensive network of linear disturbances in the basin. To adequately protect this rare genetically-pure stock of a designated Threatened species, large parts of the extensive network of roads, trails, cutlines and pipelines connected to the drainage system need to be removed from the basin or disconnected from the stream network, and the landscape restored.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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 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".