Holocene and historical vegetation change and fire history on the north-central coast of California, USA
Bibliographic record
Abstract
Pollen, non-pollen palynomorphs (NPPs), and charcoal particle stratigraphies are used to determine environmental change at Glenmire, Point Reyes Peninsula, northcentral coastal California, over the last c. 6200 years. Pollen was not preserved in early Holocene sediments when climate was drier than present. However, groundwater tables rose after c. 6200 cal. BP, allowing for greater subsequent preservation of organic matter. Middle and late Holocene environments were a mosaic of vegetation types, including mixed conifer forest with coastal scrub grassland prior to c. 4000 cal. BP. Subsequently, hardwoods such as alder ( Alnus) and coastal scrub (e.g. Artemisia, Baccharis) expanded until c. 2200 cal. BP, followed by tanoak ( Lithocarpus densiflorus), Douglas fir ( Pseudotsuga menziesii), and coast redwood ( Sequoia sempervirens). With increasing amounts of oak ( Quercus), this mosaic of vegetation types continued to dominate until the arrival of Euro-Americans in the early to mid-1800s. The fire history is probably tied closely to human settlement, since natural ignitions are rare. Elevated charcoal amounts coincide with increased sedentism of the native populations by about 3500 cal. BP. Increased sedentism may have caused a more intense and constant use of the coastal environment around Glenmire. For the most recent centuries, we compared historical records of explorations, Spanish Mission establishment, consolidation of the native Coast Miwok population, ranching by Mexican nationals, and dairying by Americans at the height of California’s gold rush with the paleoecological record. The Glenmire record thus documents changing fire use following the ad 1793 fire suppression proclamation; declines in native forest species; introductions of non-native species, including those associated with livestock grazing and land disturbance; and an increase in coprophilous fungi (NPPs) associated with the presence of large numbers of sheep and cattle, among other changes. During the historical period, the sedimentary record of historical fires closely matches the nearby fire-scar tree-ring record.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".