Effects of ontogenetic stage and density on the ecological role of the signal crayfish (<i><i>Pacifastacus leniusculus</i></i>) in a coastal Pacific stream
Bibliographic record
Abstract
Ontogenetic stage and density of consumers can affect the intensity of their roles within a community. These roles can be further complicated in a heterogeneous environment, where a consumer might have disparate effects in different microhabitat types. We conducted an enclosure experiment in a small temperate stream to test the differential ecological roles of adults and juveniles of the signal crayfish (Pacifastacus leniusculus) in 2 microhabitat types. In addition, we manipulated numbers of each stage to create a gradient of density (and biomass). Enclosures contained 1, 2, or 3 adults, or 4, 8, or 12 juveniles. Control enclosures lacked crayfish. We added leaf packs the 4 corners of the enclosures to provide a primary resource for crayfish and other invertebrates and to provide a detritus-based microhabitat. After 6 wk, we collected the leaf packs and a cobble-bottom (Surber) sample from the center of the enclosures. We used cobble-bottom samples to analyze the composition of the community in the cobble microhabitat. Leaf-pack breakdown rate was positively related to crayfish biomass for adults and juveniles. Leaf-pack invertebrate community composition and abundance were negatively affected by crayfish presence, but these results were independent of crayfish ontogenetic stage and total biomass. The composition of the cobble-bottom invertebrate community was not significantly affected by the presence of crayfish, regardless of density or ontogenetic stage. This result might have been the consequence of the cannibalistic tendencies of P. leniusculus or of possible indirect effects of crayfish (e.g., bioturbation or chemical cues). Our study is among the first to be done on the ecology of P. leniusculus in its native environment. The fact that our results do not agree with those found in other studies for this organism might reflect the fact that most of what we know about this organism comes from research done where it has been introduced.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".