Mechanisms Regulating the Composition, Structure and Dynamics of Biological Communities: Insights from Freshwater Diatom Communities
Bibliographic record
Abstract
Ecologists have sought to describe the Rules of Assembly - a set of basic, tenets that would regulate the composition, structure, and dynamics of groups of organisms. To date, these Rules of Assembly have proven elusive, and several authors have postulated that the inherent complexity of natural communities precludes investigators from ever describing these rules. In this dissertation, I used data from benthic diatom communities of tropical (Lake Matano, Sulawesi, Indonesia) and temperate (Mazinaw Lake, Ontario, Canada) freshwater lakes to evaluate several novel models regarding the mechanisms that regulate the composition, structure, and relative abundance of biological communities. I demonstrated that in Lake Matano, diatom communities exhibited high degrees of small-scale patchiness and were not regulated by geographic proximity or substrate characteristics. The small scale patchiness exhibited by this system was a result of a high degree of ecological specialization among the diatom taxa of the lake. Such elevated levels of ecological specialization were shown to be characteristic of low-latitude habitats. In general, groups of species with higher levels of ecological specialization exhibited higher levels of taxonomic diversity and lower species abundances, and my results demonstrate that more specialized taxa tended to partition resources while generalists were more prone to competitive effects. In colonization experiments, assemblages from low latitudes proceeded quickly through the early successional period and exhibited deterministic community structure in as little as ten days. This deterministic structure was not observed in similar experiments conducted in a temperate system and succession was frequently reset by weather events. Additionally, taxa from within the tropical assemblage responded independently when subjected to a simulated upwelling event, and neither simulated nor actual disturbances invoked changes in community composition in this system. In summary, I proposed the following Rules of Assembly as they pertain to diatom communities: 1.
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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 | 0.000 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".