Changes in spatial structures of plant communities lead to functional homogenization in an urban forest park
Bibliographic record
Abstract
Abstract Aims We investigated whether biotic homogenization of plant communities occurs over three decades in a small urban protected forest, and what the possible drivers are underlying the observed changes. Location A 96 ha temperate forest, Montréal, Canada. Methods We surveyed vegetation and explanatory variables (ecological conditions, disturbances, spatial structure) in 62 plant communities in 1980 and 2011. We collected plant attributes to identify functional groups (FGs). We evaluated changes in beta diversity using tests for homogeneity of multivariate dispersions. We used space–time interaction models to assess changes in FGs spatial structures. We used multivariate analyses to identify relationship between spatial patterns and explanatory variables, and variation partitioning analyses to identify the drivers involved in beta diversity changes. Results Beta diversity declined only in the herb–shrub communities. About 35% of their FGs had significantly changed their spatial distribution over time. Those that contracted their distribution were mainly composed of plants with wind‐dispersed seeds or with low to intermediate vegetative propagation capabilities, while those that expanded were plants with fleshy fruits or extensive vegetative propagation capabilities. In 1980, communities were structured into small isolated clumps, while in 2011, clumps expanded and coalesced near disturbed areas. In 1980, the spatial assembly processes relied essentially on endogenous factors while in 2011 exogenous factors, such as disturbances, became more influential. Multivariate analyses suggested that edge effect, past agricultural disturbances, and beaver activities facilitated the decrease of beta diversity (homogenization process). Conclusions The homogenization of herb–shrub communities likely resulted from changes in their clumped spatial structure. FGs with the most adapted attributes to disperse under urban forest conditions were those that expanded spatially. Structural changes seem to have begun with an unpredictable stage governed by dispersal limitation processes, followed by a predictable stage mostly driven by land‐use legacy and disturbances.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".