Contemporaneous climate directly controls broad‐scale patterns of woody plant diversity: a test by a natural experiment over 14,000 years
Bibliographic record
Abstract
Abstract Aim Broad‐scale diversity gradients are strongly correlated with climate. This correlation may reflect direct control of richness by contemporaneous climate. Alternatively, factors that were collinear with contemporaneous climate may have affected richness (e.g. temperature during the Last Glacial Maximum, LGM). We tested the hypothesis that contemporaneous climate directly controls broad‐scale patterns of richness. If climate directly (i.e. causally) controls richness, then when climate changes, richness should vary with climate through time in the same way that richness varies with climate through space. We also tested hypotheses that suggest that patterns of richness are primarily determined by processes associated with climate at the LGM. Location North America, north of Mexico. Methods We used temperature changes over the last 14,000 years in North America as a ‘natural experiment’. We compared a proxy of woody plant family richness (based on fossilized pollen) with two reconstructions of the spatio‐temporal variation of temperature across North America at 1000‐year intervals. Results We found that the spatial and temporal regional variations in richness of woody plant families, observed at 1000‐year intervals and expressed as a function of temperature, remained quite congruent during the changing climate since the end of the Pleistocene (the last c. 11,000 years). Between 14,000 and 11,000 yr bp, lags occurred during cooling periods, when richness remained anomalously high; however, richness was not anomalously low during the rapid warming in the late Pleistocene. Richness was significantly less strongly related to climate change since the LGM. Main conclusions Our results provide a strong test of the hypothesis that, in ecological time, contemporaneous climate controls most of the broad‐scale variation in patterns of richness. Richness, independently of the responses of individual species, is likely to track current climate change, except possibly when temperature changes are very rapid.
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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 | 0.004 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".