A test of Metabolic Theory as the mechanism underlying broad‐scale species‐richness gradients
Bibliographic record
Abstract
ABSTRACT Aim To test whether the temperature dependence of individuals’ metabolic rates is the mechanism shaping broad‐scale species‐richness gradients as proposed in the Metabolic Theory of Ecology recently proposed by Allen, Gillooly and Brown. Location North America, north of Mexico. Methods Metabolic Theory predicts that the natural logarithm of species richness will be a linear function of environmental temperature (( kT ) −1 , where k is Boltzmann's constant and T is temperature in K) with a slope of −0.78. We tested these predictions using the broad‐scale variation in richness of amphibians, reptiles, trees, tiger beetles, butterflies and blister beetles. We tested whether the temperature–richness relationship was linear or curvilinear, and determined the range of temperature values (and geographical area) where the instantaneous slope of the curvilinear temperature–richness relationship was statistically indistinguishable from −0.78, after correcting for spatial autocorrelation. Results We found that for all taxa, temperature–richness relationships were curvilinear. Moreover, for five of six taxa, the slope of this relationship was close to the predicted value for only a narrow range of temperatures. Blister beetles displayed the widest temperature range that is consistent with the Metabolic Theory, covering 45% of the study's geographical area. For the remaining taxa, the geographical range in which the slope is consistent with the predicted value amounts to only 10–20% of North America. Main conclusions For a wide array of taxa in North America, temperature–richness relationships deviate from the pattern predicted by Metabolic Theory. These results demonstrate that the temperature dependence of individuals’ metabolic rates is not the sole cause of broad‐scale diversity gradients. Even in areas where factors other than temperature do not influence productivity, the data do not suggest that richness patterns are determined by the temperature dependence of metabolic rate.
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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 | 0.001 |
| 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".