Distribution and abundance of birds relative to elevation and biogeoclimatic zones in coastal old-growth forests in southern British Columbia
Bibliographic record
Abstract
This study examined birds and their association with forest structure and elevation in 1992 and 1993. The research sites were located in old-growth forest stands (251+ years) distributed between 400 and 1500 m elevation in south coastal British Columbia. The use of simple and multiple regressions revealed that the variation in mean abundance of most bird species was in part explained by elevation, and was likely due to stand structure and other factors (e.g., forage productivity) that vary with the elevational gradient. However, total bird abundance and richness responded weakly to elevation; instead, density of huge snags (≥ 100 cm DBH) per hectare more consistently accounted for the variation in these two measures.Distributions of bird species are described according to two biogeoclimatic zones—the Coastal Western Hemlock and the Mountain Hemlock. Biogeoclimatic classification, which is based on plant associations and climate, is used for forest management in British Columbia. Mean abundance of 10 bird species differed significantly between the biogeoclimatic zones in at least one of the study years. Biogeoclimatic zones also effectively classified bird species into two different communities using multidimensional scaling and mean similarity analysis. However, richness and total bird abundance did not differ significantly between zones indicating that community structure was similar, although composition and dominance differed by zone. The authors, therefore, suggest that representation of old-growth forest by biogeoclimatic zone helps maintain bird diversity. To maintain the observed distributions of bird species, however, oldgrowth habitats should be represented over the entire elevational gradient and include variation in forest stand structure.
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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 | 0.002 | 0.002 |
| 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) | 0.001 | 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".