Urban impacts on terrestrial predators via changes in the size distribution of aquatic subsidies
Bibliographic record
Abstract
The export of emergent aquatic insects is a critical energy subsidy for terrestrial food webs. While urbanization is known to alter stream communities, its effects on the size structure of these insect subsidies and the subsequent consequences for riparian predators remain poorly understood. Yet, body size, a key dimension of subsidy quality, can strongly shape resource use by terrestrial predators, given their size-dependent foraging. Here, we investigated how land impervious cover affects the body-size distribution of emergent insects and riparian spider communities along the entire length of two urban streams. We sampled and analyzed emergent insect community composition, three size-structure metrics (i.e., size-spectrum slopes, mean body size and size range) and used stable isotopes to assess spider reliance on aquatic prey. Impervious cover was the strongest driver of the emergent community structure, overriding effects of longitudinal position. Increasing impervious surface cover was associated with community homogenization, a pronounced shift toward smaller individuals, steeper size-spectrum slopes and a contraction of body-size range. Notably, total exported biomass did not change significantly, indicating that the influence of surface imperviousness manifests primarily in qualitative rather than quantitative terms. Those changes led to higher reliance on aquatic prey from riparian spiders. Our work highlights that the homogenization of aquatic prey size distribution is a powerful driver of change within riparian food webs and underscore the importance of integrating body-size composition into assessments of land
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 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 | 0.000 |
| 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 | 0.000 |
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".