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Record W7161800068 · doi:10.82308/22168

The effects of biotic and abiotic forces on species richness

2011· dissertation· en· W7161800068 on OpenAlexaboutno aff
Peter Nickson White

Bibliographic record

Venuenot available
Typedissertation
Languageen
FieldAgricultural and Biological Sciences
TopicForest Ecology and Biodiversity Studies
Canadian institutionsnot available
Fundersnot available
KeywordsAbiotic componentSpecies richnessHabitatDisturbance (geology)HerbivoreBiotic componentCaterpillarGeneralist and specialist speciesEcosystem

Abstract

fetched live from OpenAlex

One central question in ecology is why some areas have many species and others have few. Many explanations have been proposed and often the forces that drive species richness are context-dependent. These forces are divided into two general categories: biotic drivers and abiotic drivers. Biotic drivers are most commonly described in terms as top-down and bottom-up effects while abiotic drivers are commonly described in terms of climate and habitat disturbance. The objective of this thesis is to determine how these drivers affect species richness in terrestrial ecosystems. To test this I examine an insect herbivore assemblage in a disturbed forest fragment landscape in southern Canada. I use geographic information systems techniques to determine the impact of a natural episodic disturbance (i.e. an abiotic natural driver) and a chronic human disturbance (i.e. an abiotic human driver) on forest habitat quality (Chapter 1) and on a forest-dwelling caterpillar assemblage (Chapter 2). I show that ice storms result in a heterogeneous pattern of spatial damage across a forest landscape, differing depending on the type of coarse woody debris examined. These different types of coarse woody debris provide habitat for a diversity of taxa. In contrast with natural disturbance, I found that human-based disturbance do not have a positive impact on caterpillar assemblages. Pursuant to this, I explore the concept of habitat quality from the perspective of host plant identity (Chapter 3) and host plant quality (Chapter 4). I found that caterpillar assemblages have strong host plant preferences and that these preferences may depend on quadrat-scale foliar qualities (i.e. a biotic bottom-up driver) and parasitoid densities (i.e. a biotic top-down driver) at different times in the growing season. This thesis adds to a growing body of literature aimed to better understand the drivers of insect species richness across disturbed landscapes. In addition, this thesis develops several management-specific tools for measuring forest disturbance and provides valuable insight into how the selection of different tree species for planting initiatives can have important impacts on forest communities.

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 machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation 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 score0.037
Threshold uncertainty score0.073

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.002
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0010.001
Scholarly communication0.0010.001
Open science0.0000.001
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0030.000

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 head0.010
GPT teacher head0.184
Teacher spread0.173 · 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 source (direct Gemma or distilled Codex), 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

Citations0
Published2011
Admission routes1
Has abstractyes

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