Looking out for the little guy: species distribution modeling and conservation implications of the elfin skimmer Nannothemis bella (Odonata: Libellulidae)
Bibliographic record
Abstract
Nannothemis bella Uhler, 1857 (Odonata: Libellulidae), the smallest dragonfly in North America, inhabit bogs and sedge fens across their distribution, spanning from Quebec (Canada) south to Florida and west to Minnesota and Louisiana (USA). While common in the northern part of their range, N. bella is of conservation concern in the southern populations where they are disjunct and rare. Little work has been done on the ecology and geographic conservation of this species. To fill this knowledge gap, we constructed species distribution models (SDMs) to analyze the spatial distribution and climatic niche of N. bella, define factors in habitat suitability and estimate potential niche shifts under climate change and inform conservation efforts. Our present-day SDMs indicate the dominant environmental elements determining habitat suitability include the proportion of silt in soil, temperature seasonality, percentage of clay and coarse components in soil, and soil class. Our paleodistribution models show a southern distribution within the last glacial maximum, with a shift northward 8,326 to 4,200 years ago. Our projected SDMs for 2050 under RCP 2.6 and RCP 8.5 predict a significant decrease in habitat suitability throughout the entire range of N. bella. As such, N. bella is a species of conservation concern and conservation measures are imperative for its continued existence as a much-needed bioindicator for these freshwater ecosystems. Additionally, this ecological knowledge provides the foundation for identifying population sites from which to collect N. bella for future population genetic studies.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".