Empirical Implications of Food Web Constraints for Metacommunity Assembly
Bibliographic record
Abstract
Empirical metacommunity investigations remain scarce and biased toward simplified laboratory experiments or observation studies at single trophic levels, hindering generalizations of mechanism in natural systems. There is a need to expand metacommunity research into more realistic scenarios by integrating different type of biotic interactions at a range of spatial resolutions and under a range of environmental conditions. Especially, food web interactions have well-documented impacts on local and regional diversity patterns that have been untested in metacommunity research. In this thesis, I investigate empirical implications of food web constraints for insect community assembly in space. The Trophic Island Biogeography theory is a promising and parsimonious theoretical approach to integrate elements from food web theory into a metacommunity perspective. In the first chapter of this thesis I explore the implications of this theory for the establishment of arthropod feeding guilds in experimental grassland islands. I demonstrate that neither diet-based constraints nor landscape characteristics can predict the early structure of locally assembling food webs, with their establishment deriving instead from interactions between both processes as a function of diet specialization. Past work has made the connection between habitat fragmentation and the alteration of trophic control. However, mechanistic linkages with multiple stressors are needed to accurately describe potential effects of global change on consumer diversity regulation. The second chapter of this thesis tests how multiple stressors (habitat loss, fertilization, and stand perturbation) potentially spread through the food chain to affect insect herbivore diversity and spatial turnover. It shows that despite the potential for interactive effects of multiple stressors on each trophic level, plant-mediated processes mostly determined the decline in insect herbivore abundance, richness and spatial turnover, while predator-mediated effects were negligible. In complementarity with these results, the third chapter of this thesis illustrates how bottom-up trophic dependencies and dispersal-related drivers of consumer assembly can loop back to trigger higher top-down damage from consumers on plants, here an endangered native tree species of Ontario suffering from recruitment collapse. Taken together this thesis illustrates the importance of trophic dependencies for local community establishment, with important implications for biodiversity in altered landscapes.
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 | 0.003 | 0.032 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".