Native and introduced fish species richness in <scp>C</scp>hilean <scp>P</scp>atagonian lakes: inferences on invasion mechanisms using salmonid‐free lakes
Bibliographic record
Abstract
Abstract Aim Geographic patterns of species richness have been linked to many physical and biological drivers. In this study, we document and explain gradients of species richness for native and introduced freshwater fish in Chilean lakes. We focus on the role of the physical environment to explain native richness patterns. For patterns of introduced salmonid richness and dominance, we also examine the biotic resistance and human activity hypotheses. We were particularly interested in identifying the factors that best explain the persistence of salmonid‐free lakes in Patagonia. Location Chile (39° to 54°S). Methods We conducted an extensive survey of 63 lakes, over a broad latitudinal range. We tested for the importance of temperature, ecosystem size, current and historic aquatic connectivity as well as measures of human activity (road access and land use) in determining patterns of native and introduced richness. Results Introduced species richness was positively correlated with native richness. Native and introduced richness declined with latitude, increased with temperature and ecosystem size. Variation in native richness was related to historic drainage connections, while introduced richness and salmonid dominance were significantly affected by current habitat connectivity. We found a total of 15 salmonid‐free lakes, all located in remote areas south of 45°S, and all upstream of major naturally occurring physical barriers. Main conclusions Temperature, as a correlate of latitude, and lake size were key determinants of native and introduced species richness in Chilean lakes and were responsible for the positive correlation between native and introduced richness. We found no evidence for biotic resistance by native species to salmonid expansion, and although the original introductions were human‐mediated, current patterns of introduced richness were not related to human activity, as measured by road access or land use. Rather, environmental factors, especially habitat connectivity and temperature, appear to limit salmonid expansion within Chilean freshwaters.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".