A transplant experiment on the factors preventing lichen colonization of oak bark in southeast England under declining SO<sub>2</sub> pollution
Bibliographic record
Abstract
To investigate the factors responsible for limited lichen recolonization on oak with declining SO 2 concentrations, Parmelia caperata (L.) Ach. and Parmelia saxatilis (L.) Ach. were transplanted to five stations along a transect running from central London (U.K.) into the surrounding countryside. Healthy thalli were transplanted onto young and mature Quercus robur L. (pedunculate oak) and Betula pendula Roth (silver birch), and some were moved with their original bark attached to investigate the importance of bark acidification. Relative growth rates and visible injury were monitored over 2 years, along with concentrations of atmospheric SO 2 and NO 2 , measured using diffusion tube samplers and bark chemistry. SO 2 concentrations were low in central London in comparison with the situation in previous decades, but they remain sufficiently high to harm the most sensitive lichens. NO 2 concentrations increased sharply on approaching London, and levels were higher in winter than in summer. Bark pH was lower in mature oak than in birch or young oak at the two innermost stations, and levels of bark Mg also declined in London. Transplants of P. caperata survived on birch and young oak at all transect stations except Hyde Park, whereas P. saxatilis failed to grow over a wider range of the transect stations. We conclude that modest SO 2 levels, interacting with low bark pH, still inhibit recolonization of oaks by P. caperata in central London. Parmelia saxatilis, in addition, appears to be limited by another factor such as the high NO 2 concentrations that now characterize urban and suburban London, rather than through an inherently poor dispersal potential.Key words: atmospheric pollution, bark acidification, epiphytic lichens, NO 2 , recolonization, SO 2 .
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".