Biogeography and conservation of the pinnipeds (Carnivora: Mammalia)
Bibliographic record
Abstract
This thesis examines the biogeography of world pinnipeds, a unique group of marine mammals that have adapted to marine foraging while maintaining terrestrial (land or ice) habitat links. Comparative analyses of species range sizes controlled for phylogenetic relationships using a multi-gene supertree with divergence dates estimated using fossil calibrations. Adaptations to aquatic mating and especially sea ice parturition have influenced range size distribution, and ranges are larger than those of terrestrially mating and/or pupping species. Small range size is endangering for many taxa, and most at risk pinnipeds are terrestrial species with small ranges. Ancestral state reconstructions suggest that pinnipeds had a long association with sea ice, an adaptation that would have allowed early seals to expand into novel habitats and increase their distribution. Range sizes exhibit a strong Rapoport effect (positive relationship between range size and latitude) at the global scale, even after controlling for phylogeny and body size allometry. A latitudinal gradient in species diversity cannot explain the Rapoport effect for global pinniped ranges, as diversity is highest at mid-latitudes in both hemispheres. These regions are characterized by marginal ice zones and variable climates, supporting a mix of pagophilic and temperate species. The climatic variability hypothesis also did not explain the Rapoport effect. Variability is bimodal, and annual sea surface temperature (SST) variability does explain diversity patterns. Range size has a significant negative relationship with annual mean SST, and the largest ranges are found in areas with low mean SST. Temperature responses are possibly related to thermoregulation, sea ice availability, and ecological relationships with other large marine predators. These results agree with other studies and suggest that ocean temperature, and not productivity, drives marine species richness patterns. Future research needs include studies of physiological tolerances, interactions with sharks as predators and competitors, and the role of climate and sea ice in speciation and evolution. A better understanding of distribution and diversity patterns, and the role of the environment in shaping these patterns, will improve conservation efforts, and studies on the role of SST and sea ice are particularly important given current warming trends and declines in ice extent.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| 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".