Phylogenetic homogenization of bee communities across ecoregions
Bibliographic record
Abstract
Abstract Aim Land use change reorganizes local communities, resulting in complex changes in biodiversity at larger scales. The biotic homogenization hypothesis predicts that the replacement of sensitive loser species with widespread winner species will lead to loss of beta diversity and ultimately loss of regional diversity at multiple levels of ecological organization. We ask if land use is associated with biotic homogenization patterns in bee communities at two large spatial scales, using both species and phylogenetic dissimilarity indices. Location North‐eastern USA (New Jersey, New York and Pennsylvania). Time period 2013–2015. Major taxa studied Superfamily Apoidea (bees). Methods We sampled bee communities from replicated sites in forest, agriculture and urban land use types within a large spatial extent spanning four distinct ecoregions. We compared pairwise compositional dissimilarity within and between ecoregions, using both species and phylogenetic dissimilarity indices. We also investigated how compositional difference is related to geographic distance between sites. Results Forested, agricultural and urban landscapes did not differ detectably in either mean pairwise species dissimilarity or slope of distance‐decay. Dissimilarity among both agricultural and urban bee communities increased with geographic distance. However, urban landscapes had significantly lower phylogenetic pairwise dissimilarity, indicating strong phylogenetic homogenization at within‐ and between‐ecoregion scales. Main conclusions We did not detect bee species homogenization in agricultural or urban land use types. However, urban land use was associated with phylogenetic homogenization across a large regional extent. Urban bee communities are dominated by closely related species that maintain beta diversity at the species level, but contribute to low phylogenetic beta diversity relative to forest and agricultural bee communities. We observed similar levels of homogenization at landscape and regional spatial extents, despite inter‐site distances differing by an order of magnitude between these scales. Further urbanization could result in loss of bee biodiversity and evolutionary history at multiple spatial scales.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| 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".