Long-term changes in river-floodplain dynamics : implications for salmonid habitat in the Interior Columbia basin, USA
Bibliographic record
Abstract
Salmonids (salmon and trout) are threatened, endangered or at-risk throughout much of their historic range in western North America. However, a lack of detailed information about historic floodplain, riparian and channel condition makes it difficult to disentangle potential causes of population declines (e.g., habitat degradation vs. overfishing). For this research, historic habitat was reconstructed along five salmonid-bearing tributaries of the Columbia River using historic (1949) aerial photographs. Historic airphotos were scanned and orthorectified to create a 0.5 m resolution orthomosaic compatible with a USDA National Agricultural Imagery Program (NAIP) compressed county mosaic of modern (2006) imagery. Floodplain extent, land cover and stream reach type, as well as several types of floodplain and channel habitat important to salmonids, were delineated manually for both time periods. These features were compared between 1949 and 2006, across the five tributaries and at the reach level, using a combination of transition matrices, paired t-tests and ANOVAs. Quantifying these features helped provide historic and modern landscape-level indicators of floodplain, riparian and riverine condition. The predominance of historic agriculture and contemporary urban expansion have likely reduced important salmonid habitat features in the Wenatchee system. Transitions of island braided channels to straight reaches were associated with significant reach shortening and increased anthropogenic modification to floodplain and riparian areas. When comparing the 1949 and 2006 landscapes, a loss of meandering reaches coincided with a reduction in the types of off-channel habitats associated with lateral channel migration (such as slow/stagnant and dry channels). Increased fragmentation of remaining habitat in highly modified river-floodplains may reduce the accessibility of contemporary floodplain habitat to salmonids. Unavoidable mapping error (due principally to solar glare) likely contributed to overestimating the historic predominance of straight reach types and an underestimate of island braided reaches. This research provides an example of how anthropogenic activities may have contributed to declines in high quality salmonid habitat in the study area and can guide the prioritization of restoration efforts. The general methodology developed here can be adapted to other river floodplains throughout Canada and the USA where extensive anthropogenic modification may be of management concern.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".