The utilisation of coprophilous fungal spores for discerning late Quaternary megaherbivore extinctions in Canada
Bibliographic record
Abstract
Northern ecosystems are experiencing dramatic changes due to anthropogenically accelerated climatic warming. Understanding the impacts of this on fauna and flora is key to predicting the long-term sustainability of northern environments. This requires long-term data sets of ecosystem response to environmental change from environments and climates contiguous to contemporary conditions. One event is the climatic warming recorded at the Pleistocene- Holocene transition that resulted in the extinction of 35 megafaunal genera and loss of the mammoth steppe biome in East Beringia. Previous studies have relied on spatially and temporally correlating bone remains, but coprophilous fungi preserved in lake sediments have recently been used as a complimentary proxy for reconstructing megaherbivore populations. A high-resolution record spanning this transition has been reconstructed using a sediment core collected from Gravel Lake, central Yukon Territory. Pollen and coprophilous fungi were complimented by radiocarbon-dated bone remains from Alaska and Yukon Territory. Results indicate the local extirpation of megaherbivores at the beginning of the Holocene (ca. 11,000 to 10,400 cal yr BP) by a decline in coprophilous fungi and a lack of bone remains from Yukon Territory. However, skeletal records indicate the loss of mammoths and horses at ca. 13,000 cal yr BP, 2000 years prior to the fungi records. At this time, pollen assemblages from Gravel Lake indicate the last environments contiguous with the mammoth steppe from this region. The data highlight a faunal turnover at ca. 13,000 cal yr BP with the proliferation of browsing taxa, but it is still unclear why only mammoth and horse populations are lost and not other grazing taxa such as bison and muskox. A secondary study analysed remains preserved in mastodon dung dated to the marine isotope stage 5a/4 transition of Nova Scotia. Results indicate a wetland rich in charophytes, sedges, cattails, bulrushes and bryophytes in a spruce-dominated boreal forest. The limited diversity and abundance of coprophilous fungi in the dung could be attributed to a browser feeding habit. If so, this could have a considerable impact on understanding the influence of feeding ecologies on the presence of coprophilous taxa in lake sediments, and thus inferences of megaherbivore abundance.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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 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".