The theory of island biogeography, the sample‐area effect, and the habitat diversity hypothesis: complementarity in a naturally fragmented landscape of lake islands
Bibliographic record
Abstract
Abstract Aim Investigate relationships between fragmentation and species diversity in the context of the theory of island biogeography, sample‐area effect, and habitat diversity hypothesis. Location Lake of the Woods, Canada. Taxon Vascular plants Methods Vascular plant species diversity was inventoried on 30 islands, organized into two island sets. Each island set contained four size classes that varied in degree of fragmentation while controlling for the sample‐area effect (small island set: 8 × 0.1‐ha, 4 × 0.2‐ha, 2 × 0.4‐ha, and 1 × 0.8‐ha islands; large island set: identical pattern utilizing 1.0‐ha to 8.0‐ha islands). Fragmentation effects were then examined usingSLOSS‐based analyses, addressing whether single large or several small islands contained more species/habitats: (a) direct comparisons of species and habitat richness across size classes; (b) extrapolations of species–area relationships; and (c) analyses of species and habitat accumulation curves. Multigroup path analysis was next used to quantify effects of habitat diversity, island area, and isolation on species richness for both island sets. Finally, pairwise and multiple‐site dissimilarity was estimated for both species and habitats across 0.1‐ha and 1.0‐ha islands to investigate whether: (a) variation in species composition was related to habitat composition; and (b) species dissimilarity increased with inter‐island distance. Results SLOSS‐based analyses indicated that several small islands contained more species than single large islands in both island sets. This pattern was also observed for habitats, but only in the small islands set. Path analysis suggested that island area had significant direct and indirect (mediated by habitat diversity) effects on species richness. Habitat diversity and island isolation had significant positive and negative effects on species richness, respectively, independent of island area. Species and habitat dissimilarities were significantly related across 0.1‐ha but not 1.0‐ha islands, and showed no relationship to inter‐island distance. Main conclusions The overall positive relationship between fragmentation and species richness may be attributed to greater habitat diversity and increased species dissimilarity across smaller islands relative to larger islands. However, negative isolation effects indicate that landscape configuration is still an important conservation consideration. These results each align with different predictions of the theory of island biogeography, sample‐area effect, and habitat diversity hypothesis, questioning the exclusivity of these theoretical frameworks.
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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 | 0.002 | 0.010 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.003 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".