Evidence for limited trophic transfer of allochthonous energy in temperate river food webs
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The River Continuum Concept (RCC) predicts that riverine food webs shift from a reliance on allochthonous energy in headwaters to autochthonous production in lower reaches. However, estimates of resource reliance often fail to account for resource segregation within the food web. Stable-isotope biomarkers can be used to estimate the relative importance of allochthonous and autochthonous material to specific groups and within the food web. δ13C and δ15N isotope ratios were calculated for allochthonous (conditioned leaf litter) and autochthonous (biofilm and bryophytes) basal energy sources, macroinvertebrate functional feeding groups (shredder, grazer, collector–filterer, collector–gatherer, predator), and resident fish species at 17 locations spanning the headwaters to lower reaches of 2 river systems in eastern Canada. Stable-isotope mixing models and correlations were used to identify longitudinal trends in the food webs of both rivers. In headwater streams, allochthonous material was the predominant resource for shredders, whereas all other primary, secondary, and tertiary consumers predominantly used autochthonous basal resources. Stable-isotope ratios of allochthonous material varied minimally between sites. Both autochthonous basal sources were significantly 13C-enriched and 15N-depleted in lower-reach relative to headwater sites. Shredders displayed minimal variation across sites, whereas longitudinal variation in all other primary consumers, macroinvertebrate predators, and fishes was closely correlated with autochthonous basal sources. These results highlight the role of resource segregation within river food webs and indicate that the RCC may not predict energy pathways in all temperate river systems.
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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 | 0.002 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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 it