Improvements in water clarity and submersed aquatic vegetation cover after exclusion of invasive common carp from a large freshwater coastal wetland, Delta Marsh, Manitoba
Bibliographic record
Abstract
Once introduced to shallow aquatic ecosystems common carp (Cyprinus carpio) often degrade habitat, negatively impacting the native organisms that rely on these systems. Detrimental effects often observed following the introduction of carp include a reduction in water clarity as bottom sediments become disturbed and resuspended and phytoplankton blooms become more severe and frequent. This results in a reduction of submersed aquatic vegetation (SAV), the effects of which are felt across multiple trophic levels. We sought to limit large carp (>70 mm maximum body width) access to a culturally and biologically significant 18,500 ha freshwater coastal wetland located in Manitoba, Canada to restore pre-carp conditions which were characterized by clear water and abundant SAV. In winter 2012–2013, exclusion structures were built to limit access by large carp to Delta Marsh during the spring and summer. A monitoring program (2009–2018) compared marsh conditions before and after carp exclusion. Water clarity improved following carp exclusion, largely driven by a reduction of inorganic suspended solids (ISS) rather than phytoplankton biomass, indicating that maintaining clear water conditions might be supplemented by reductions in nutrient export from agricultural areas adjacent to the marsh. The decrease in ISS and phytoplankton varied spatially, with the greatest change observed in the westernmost area of the marsh which is more sheltered compared to the large open bays characterizing eastern areas of the marsh. SAV doubled in percent cover through the 6 years of monitoring post-carp exclusion and SAV cover and species richness in the marsh was comparable to what was present in the early 1970s when there was also partial carp exclusion. Similar to water clarity, the increase in SAV cover was most significant in sheltered areas of the marsh. Our results suggest that excluding large carp can improve water clarity, SAV cover, and SAV species richness in large freshwater wetlands, benefiting waterfowl and other species.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".