Accuracy, uncertainty, and biases in cumulative pressure mapping
Bibliographic record
Abstract
• Our study addresses biases and uncertainties of cumulative pressure maps. • Map’s accuracy significantly improves with an increase in the number of layers. • Uncertainties in intensity scores moderately affect overall accuracy. • Additive and antagonist cumulative models exhibit a robust correlation. Understanding how human activities are altering landscapes is critical to address habitat loss and biodiversity decline. Cumulative pressure mapping has emerged as a tool to quantify both the extent and intensity of multiple forms of human activities on the environment. However, there are several approaches to selecting and combining individual spatial layers into cumulative pressure maps, without clear guidance on how these methods affect the accuracy of the resulting maps. Here, we evaluated how the number of individual pressures, and changes in their intensity scores influenced the accuracy, measured against visual interpretation of high-resolution imagery, of a cumulative pressure map for a large, ecological diverse province, British Columbia, Canada. Additionally, we compared additive and antagonist models for combining pressures, which are among the most widely employed models in terrestrial studies. We started by identifying 16 human pressures and their associated spatial representation (i.e., layer) across the province. We then compared the validation values and the outcomes of 100,000 simulations in which we tested different perturbations of the human pressure model. Model accuracy improved with the inclusion of each additional pressure layer, reaching an average mean absolute error of 0.09 with the full spectrum of pressures. Our findings suggested that variations in intensity scores assigned to individual pressures only moderately influenced the resulting cumulative pressure score. In our final analysis, we observed a robust correlation between the additive and the antagonist models, particularly in regions that were either relatively free of human disturbance or highly modified by disturbances. Our study provides an empirical basis for continued improvements to practices for cumulative pressure mapping, addressing methodological challenges that were not formally considered in previous studies.
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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 | 0.021 | 0.110 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.005 | 0.004 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.001 | 0.002 |
| 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".