Early Holocene glacial retreat isolated populations of river otters (<i>Lontra canadensis</i>) along the Alaskan coast
Bibliographic record
Abstract
Pleistocene climatic oscillations have resulted in high rates of speciation. Lesser known are speciation events related to recent glacial retreats. During the early Holocene many Alaskan coastal glaciers receded, exposing much of the Kodiak Island Archipelago (KOD), the Kenai Peninsula, and Prince William Sound (PWS). Using fecal DNA analyses on samples collected in KOD, PWS, Kenai Fjords National Park (KEFJ), Katmai National Park and Preserve (KATM), and Vancouver Island, British Columbia (BC), we found isolation by distance to be an important mechanism for the divergence of populations of river otters ( Lontra canadensis (Schreber, 1777)) along the Pacific coast. Nonetheless, our results also demonstrated that KOD river otters appear to be more isolated genetically from their mainland conspecifics (approximately 50 km away), as river otters inhabiting PWS are from those in BC (over 2500 km away). In addition, KATM and KOD otters likely differentiated from one ancestral stock that inhabited the southwestern shores of Alaska during the Pleistocene and was isolated from more easterly populations by distance. The low genetic diversity among KOD river otters, compared with similar subpopulations in PWS, is likely the result of a founder effect and limited gene flow among the different islands within the Archipelago. Our observation that glacial retreat, rising sea levels, and formation of the Gulf of Alaska Coastal Current in the early Holocene likely led to divergence of populations of river otters, a highly mobile semiaquatic mammal, highlights the potential for future speciation events related to current climate change and ocean currents in coastal animal populations.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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 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".