Temporal Change in Crayfish Communities and Links to a Changing Environment
Bibliographic record
Abstract
Community ecology and conservation are complementary disciplines under the umbrella of ecology, providing insight into the factors that determine where and how communities exist, and informing efforts aimed at sustaining the diversity and persistence of the organisms that comprise them. Conservation ecologists apply the principles of ecology and other disciplines, to the maintenance of biodiversity. This thesis uses this approach to assess the status of freshwater crayfish in south-central Ontario and investigate potential anthropogenic drivers of crayfish community change. I start with a temporal analysis of crayfish relative abundance over a period of 18 years and find that all species have experienced significant population declines across the sampled range, resulting in reduced species distributions and crayfish community diversity. Next I employ multivariate statistical techniques to relate changes in crayfish communities between the two time periods to ecological and anthropogenic changes. I identify a number of threats in the region that are correlated with crayfish decline and are likely to pose a threat to aquatic ecosystems more broadly in the region, including calcium (Ca) decline, metal pollution, human development, and species introductions. In the latter two chapters I look more closely at Ca decline as a mechanism driving crayfish declines. First, laboratory analysis of the effect of Ca availability on juvenile Orconectes virilis (a Shield native) reveals that survival is significantly reduced below 0.5-0.9 mg·L-1, which is one of the lowest ever reported Ca requirement thresholds for a crustacean. Second, a correlative study using adult inter-moult crayfish collected from lakes that range broadly in their Ca concentrations, indicates that for O. virilis, carapace Ca content is significantly related to lake Ca concentration, and is under-saturating below 8 mg·L-1. This collective body of work identifies significant anthropogenic threats to crayfish and their aquatic ecosystems in south-central Ontario.
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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 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".