not-yet-known not-yet-known not-yet-known unknown Large-scale source-sink dynamics in Tachycineta bicolor breeding in southern Québec’s farmlands
Bibliographic record
Abstract
not-yet-known not-yet-known not-yet-known unknown Avian insectivores have experienced population declines worldwide, with intensification of agricultural practices as a major contributing factor. To understand how species react to such human-driven environmental changes, it is necessary to obtain detailed information on their survival, reproduction and dispersal. This is particularly important for declining species and populations, where immigration contributed by dispersers from neighboring populations can influence local population growth. We used multi-state Capture-Mark-Recapture (CMR) models and 14 years of data (2004-2019) on individually marked Tree Swallows (Tachycineta bicolor) breeding on farmlands in southern Québec, Canada, to quantify the effects of agricultural intensity, local weather, and interspecific competition on the vital rates and population growth. Yearly population growth rates were highly dependent on both immigration and adult return rates. Nest site competition by House sparrows (Passer domesticus), mostly found within intensively cultivated landscapes, had a strong negative effect on reproductive success and adult return rates. Nevertheless, 43% of the variance in lambda was attributed to unexplained differences between farms, suggesting that microhabitat or other unmeasured environmental variables also drive population growth rate. Our results clearly show that the studied population would not persist without immigration, suggesting that intensively cultivated farmlands may act as sinks. Our sampling design may partly explain this result as nest boxes were installed in low quality habitats. Understanding the ecology and demography of declining aerial insectivore species therefore requires studying multiple populations of the same species in a wide range of habitats and geographic locations, as well as several species with contrasting life histories.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| 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".