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Record W1515525646 · doi:10.20381/ruor-16197

Disturbance and biodiversity.

2001· dissertation· en· W1515525646 on OpenAlexvenueaboutno aff
Robin L. Mackey

Bibliographic record

VenueLibrary and Archives Canada (Government of Canada) · 2001
Typedissertation
Languageen
FieldEnvironmental Science
TopicPlant Ecology and Soil Science
Canadian institutionsnot available
Fundersnot available
KeywordsDisturbance (geology)BiodiversityGeographyEnvironmental scienceEcologyEnvironmental resource managementBiologyPaleontology

Abstract

fetched live from OpenAlex

General opinion in the contemporary literature is that disturbance strongly influences patterns of species diversity, and that diversity is greatest at intermediate levels of disturbance. However, empirical evidence is equivocal, and quantitative predictions about the strength of diversity-disturbance relationships are lacking. Using Markov models of dynamics of real communities, I derived predicted changes in diversity when communities are subjected to quantified disturbance gradients. I also derived predictions regarding effects of sampling intensity and species selectivity of disturbance on diversity-disturbance relationships. My models predict peaked relationships should be relatively rare, variation in diversity over disturbance gradients typically should be low, and relationship shape varies with sampling intensity. These results are broadly consistent with a review of published diversity-disturbance relationships. A meta-analysis of 197 published diversity-disturbance relationships was performed to determine how frequently observed relationships are peaked; how strong, in general, relationships are; and whether various attributes of a study influence the observed shape and strength of a relationship. Non-significant relationships were the most common, and peaked responses were reported in only 16% of cases. Variation in diversity explained by disturbance was variable, but averaged ∼50%. Results suggest that strong and/or peaked relationships may arise from procedural artifacts. I conclude that there is little evidence to support the belief that disturbance should have a consistently important role in determining patterns of diversity, or that diversity-disturbance relationships are typically peaked. Anthropogenic habitat loss is often cited as the most important cause of recent species' extinctions. Recent studies identifying hot spots of imperiled species have suggested that habitat loss is the primary factor threatening the survival of imperiled species. However, interpretation of such hot spots is not practical without knowledge of where imperiled species have been lost. I determined distributions of richness and losses of imperiled species in Canada, and statistically examined the relationship between species' losses and various landuse variables. Several hot spots of losses were identified in southern regions of Canada. The combination of frequent and intensive insecticide applications, routine herbicide use, and habitat loss due to agricultural development appears to be the most important threat to imperiled species.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

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)0.000
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 score0.364
Threshold uncertainty score0.940

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
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 head0.002
GPT teacher head0.122
Teacher spread0.120 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

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".

Quick stats

Citations1
Published2001
Admission routes2
Has abstractyes

Explore more

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