Recent climate warming favours more specialized cladoceran taxa in western Canadian Arctic lakes
Bibliographic record
Abstract
Abstract Aim Shifts in the distribution of freshwater algal communities as a result of climate‐related limnological changes are well documented; however, impacts on higher trophic levels have received less attention. For example, little is known about how Cladocera (Crustacea, Branchiopoda), often dominant invertebrates and key ecological indicators, have responded to recent warming on broad spatial and temporal scales. Here, we use lake sediment records to test the hypothesis that recent, intensive warming in the western Canadian Arctic has resulted in consistent shifts in the composition of cladoceran assemblages. Location Small, first‐order lakes in the Mackenzie Delta region of the western Canadian Arctic. Methods Sediment cores representing the recent past (approximately 150–200 years) were obtained from five lakes spanning a strong climatic gradient. Subfossil remains of Cladocera were identified and enumerated and overall primary production was inferred using spectroscopic techniques. The habitat preferences and feeding strategy of each taxon were compared. Detrended canonical correspondence analysis was used to estimate compositional turnover since 1850, and compared with that of three cladoceran assemblages from Nova Scotia, to place high‐latitude changes in context. Results Cladoceran assemblage changes occurred coincident with the timing of known regional warming and were strongly linked to estimated changes in primary production. In the northern and deepest lakes, an increase in the planktonic, filter‐feeding taxon Bosmina spp. coincided with a decrease in the generalist littoral taxa Chydorus cf. brevilabris and Alona circumfimbriata . In the more southern lakes, an increase in macrophyte‐associated scrapers Acroperus harpae and Eurycercus spp. occurred concurrently with decreases in generalist taxa. In one lake, an increase in another specialist, an obligate mud‐dwelling taxon, was observed. Main conclusions In the western Canadian Arctic, warming has resulted in an increase in cladoceran taxa occupying more specialized feeding and habitat niches. Generalist taxa capable of occupying multiple habitats and employing diverse feeding strategies have been systematically replaced by more specialist species. This response is analogous to what has been inferred for algal communities across the Northern Hemisphere, and represents the first evidence of consistent cladoceran changes to recent climate warming in high‐latitude regions.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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".