Microhabitat selection by the amphipods Echinogammarus ischnus and Gammarus fasciatus in laboratory and field experiments
Bibliographic record
Abstract
The Ponto-Caspian amphipod Echinogammarus ischnus was first detected at a lone site in the lower Detroit River in 1995, and has quickly spread through the lower Great Lakes. Analysis of archived samples revealed that Echinogammarus was present in the western basin of Lake Erie at Middle Sister, East Sister and Pelee Islands during June 1994. Moreover, body length sizes classes demonstrate that Echinogammarus was a fully reproducing population with different generations at the time of collection in 1994, and that it most likely invaded Lake Erie no later than 1993. It has been suggested that it is displacing the native amphipod Gammarus fasciatus and that replacement of amphipod species could have far-reaching implications. However, no mechanistic studies have been conducted in the laboratory or field to assess habitat preference by invading Echinogammarus or its effects on resident Gammarus populations. Thus, the invasion of Lake Erie by Echinogammarus provides an excellent opportunity to explore interspecific interactions between resident and invading amphipod species. Laboratory and field experiments reveal the interaction between these two species is neutral over short time periods, commensal over brief periods, and negative over longer periods due to abundance patterns of each species. Biomass of Cladophora encrusted on rocks had no effect on Echinogammarus abundance, but it did have positive effects on Gammarus' abundance. Echinogammarus abundance was positively affected by Dreissena -encrusted biomass, while Gammarus abundance fluctuated on Dreissena-encrusted biomass. Thus, introduction and spread of Dreissena in the Great Lakes appears to have facilitated Echinogammarus' colonization, establishment and dispersal in a manner consistent with Simberloff and Von Holle's 'invasional meltdown' hypothesis. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2000 .V355. Source: Masters Abstracts International, Volume: 40-03, page: 0660. Adviser: Hugh J. Macisaac. Thesis (M.Sc.)--University of Windsor (Canada), 2000.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".