Pervasive changes to the lower aquatic food web following <i>Nitellopsis obtusa</i> establishment in a large, shallow lake
Bibliographic record
Abstract
Abstract Nitellopsis obtusa was first reported in North America in 1974. The overall ecological threat that N. obtusa poses towards freshwater ecosystems in its non‐native range is thought to be similar to other invasive macrophyte species. However, few studies have evaluated the impacts to aquatic communities upon successful establishment of this species in North America. Despite N. obtusa being a non‐native invasive species in North America, it is considered a beneficial macrophyte within its native range in Eurasia We evaluated the impacts associated with the non‐native invasive charophyte N. obtusa on the lower aquatic food web (LAFW) communities (phytoplankton, macroinvertebrates, and macrophytes) in a large, shallow lake in Ontario, Canada. To tease apart abiotic and biotic factors that influence LAFW species assemblages, a generalised linear latent variable model (GLLVM) was used. Over the course of the 4‐year study period, N. obtusa abundance significantly increased throughout the lake (pairwise comparison, p < 0.001) and notable shifts in community composition occurred across years (PERMANOVA, p < 0.001), especially for the phytoplankton and macrophyte communities. Nitellopsis obtusa was also found to be associated with a decline in diversity, where Simpson's diversity indices across all LAFW communities decreased as a function of increasing N. obtusa biomass. The GLLVM analysis revealed significant negative associations between N. obtusa and the majority of LAFW taxa. Most notably, there was a significant ( p < 0.001) negative relationship between Myriophyllum spicatum , a previously established non‐native invasive macrophyte, and N. obtusa . The GLLVM model also demonstrated that N. obtusa had positive co‐occurrence relationships with other members of the macrophyte community including Utricularia vulgaris , Najas flexilis , Potamogeton crispus , and Stuckenia pectinata . These results show for the first‐time significant impacts to the LAFW in an invaded ecosystem, which raises major concerns for fish communities that depend on the LAFW for food and habitat. Further studies are necessary to confirm the extent of these impacts in other invaded lakes.
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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 | 0.000 | 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".