Climate and the distribution of C<sub>4</sub> grasses along the Atlantic and Pacific coasts of North America
Bibliographic record
Abstract
In this study, relationships between temperature, precipitation, and the percentage of C 4 grasses in local grass floras from the Atlantic and Pacific coastal regions of North America were examined. The proportion of C 4 species in a local grass flora increased as latitude decreased on both coasts. At a given latitude, the C 4 percentage on the Atlantic coast was higher than the Pacific coast. This difference was related to the Atlantic coast having greater July minimum temperatures than Pacific coast locations of similar latitude. Linear regression analysis showed that the proportion of C 4 species in a local flora was positively associated with July minimum temperature on both coasts. The regression line between July minimum temperature and C 4 representation was similar for each coast, indicating growth-season temperature has a similar control over C 4 presence on the two coasts. Proportionally more of the annual precipitation fell in midsummer on the Atlantic than the Pacific coast, but this difference in the seasonal occurrence of precipitation did not alter the relationship between July minimum temperature and the contribution of C 4 grass species to local floras. The Atlantic coast locations with the most precipitation had the highest C 4 grass occurrence, indicating aridity alone did not increase the C 4 representation in a grass flora. On both coasts, the proportion of NADP-malic enzyme C 4 species in local C 4 grass floras was positively correlated with mean annual precipitation; however, at equivalent percentages of NADP-malic enzyme subtype occurrence, precipitation levels were substantially lower on the Pacific than Atlantic coast. The trend between latitude and the percentage of C 4 species in exotic grass floras was similar to the trend between latitude and the percentage of all C 4 grasses in an entire grass flora. Thus, the C 4 pathway appears to play no obvious role in enhancing the invasibility of exotic grasses in North America.Key words: bioinvasions, biogeography, C 4 photosynthesis, C 4 subtype, Poaceae, photosynthesis.
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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 | 0.000 | 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 | 0.001 |
| 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".