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Regional and local effects of disturbance and climate on altitudinal treelines in northern Patagonia

2003· article· en· W4231905495 on OpenAlex
Lori D. Daniels, Thomas T. Veblen

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueJournal of Vegetation Science · 2003
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicTree-ring climate responses
Canadian institutionsUniversity of British Columbia
Fundersnot available
KeywordsEcotoneDisturbance (geology)PrecipitationPhysical geographyVegetation (pathology)Tree lineClimate changeGlobal warmingClimatologyEnvironmental scienceEcologyGeographyGeologyGeomorphologyHabitat

Abstract

fetched live from OpenAlex

Abstract. In this field study we analysed the regional and local scale effects of disturbance and climate on altitudinal treelines dominated by Nothofagus pumilio in northern Patagonia. We compared two regions west and east of the Andes at 40° S, slopes with warm vs cool aspects and undisturbed vs locally disturbed treelines. This spatial framework allowed us to test (1) for differences among treelines affected by different types of local disturbance and (2) the traditional hypothesis that low temperature limits treeline. Contingency tables and ANOVA showed that local disturbance occurred more frequently than expected on slopes with cool aspects, steep slope angles and concave slope configuration. Disturbed treelines were locally lowered with longer ecotones and lower krummholz growth rates and vegetation cover than undisturbed treelines. Three‐way ANOVA showed the significant influences of study area (regional climate) and aspect (local climate) on treeline elevation, krummholz growth rates and density, tree density and vegetation cover, while accounting for local disturbance. Treeline elevations were higher east of the Andes reflecting the more continental climate in Argentina than in Chile, plus regional impacts of volcanic eruptions. Tree density and vegetation cover were greater west of the Andes reflecting greater precipitation in Chile. Within study areas, local climate had different influences on treeline elevations and krummholz growth rates west and east of the Andes. We predict that increased tree growth and upslope advance of treeline in response to global warming is more likely in Chile than in Argentina near 40° S, unless precipitation increases east of the Andes. To test these predictions, we recommend research be stratified to account for the influences of local disturbance, which may confound climatic impacts. In northern Patagonia, suitable control (undisturbed) study sites will most likely be found at upper slope positions with low slope angles, simple microtopography and straight topographic configuration.

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Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.020
Threshold uncertainty score0.202

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.016
GPT teacher head0.258
Teacher spread0.242 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it