Insect seed and cone predation reduces reproductive potential of treeline conifers across northern Canada
Bibliographic record
Abstract
Abstract Aim Altitudinal and latitudinal treeline ecotones have not consistently responded to climate warming in the direction and/or magnitude predicted by climate alone, suggesting that non‐climatic mechanisms (e.g. biotic interactions) also mediate treeline range dynamics. Through a collaborative research approach, we assessed environmental conditions associated with pre‐dispersal insect cone granivory and how this biotic interaction may govern the reproductive potential, and therefore range dynamics, of spruce‐dominated treelines across northern Canada. Location In all, 10 boreal forest treelines, tundra and alpine, from Yukon to Newfoundland and Labrador, Canada. Taxa White spruce ( Picea glauca [Moench] Voss), Black spruce ( Picea mariana [Mill.] B.S.P.), Strobilomyia spp., Megastigmus spp. Methods Treeline sites were assessed for presence and magnitude of pre‐dispersal seed granivory by insects along with viable seed availability. We quantified stand density metrics, organic layer depth and understorey vegetation composition at each location and, subsequently, incorporated those variables into generalized linear mixed models to establish predictors of granivory magnitude and viability of available seed. Results Insect granivory was widespread across sites; however, site‐specific patterns of granivory were associated with increased moss cover and decreased shrub cover and stand density. While all black spruce‐dominated sites exhibited seed viability rates > 50%, the number of seeds produced per cone varied, suggesting that within‐site abiotic conditions and biotic interaction pressures limit successful colonization of novel environments in advance of seed dispersal. Main Conclusions The modelled relationships between granivory, seed viability and environmental conditions represent an essential step towards generalizing how and when biotic interactions across subarctic treelines influence boreal tree range dynamics before seed dispersal. Connections between granivory magnitude and site‐level treeline characteristics (e.g. stand density, understorey vegetation) will provide a more comprehensive understanding of treeline range dynamics under continued climate change.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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 teacher head, 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".