Dynamics and trends of overwintering colonies of the monarch butterfly in Mexico
Bibliographic record
Abstract
There are two breeding migratory populations of the monarch butterfly (Danaus plexippus) in North America. A comparatively small, Western population migrates from states west of the Rocky Mountains to California, and a large Eastern population migrates from southern Canada and the United States to central Mexico. We monitored the dynamics and trends of monarch overwintering colonies in Mexico from the 2004–2005 to the 2013–2014 seasons. Of 19 colonies, 14 were inside the Monarch Butterfly Biosphere Reserve and five were outside the reserve. The number of colonies with butterflies varied among years, and in only three colonies were butterflies consistently present in all seasons. The total cumulative area of forest used by all monarch colonies in all seasons was 106.53 ha: 83.68% inside the reserve and 16.32% outside the reserve. By the 2013–2014 season, however, the surface occupied by monarchs (0.67 ha) had decreased 44% from the previous season, and is the smallest in two decades, far from the highest record of 18.19 ha in the 1996–1997 season. Extensive loss of breeding habitat by eradication of common milkweed (Asclepias syriaca, the primary food source for monarchs) from herbicide use and land-use changes in the United States, extreme climate conditions in Canada, the United States and Mexico, and deforestation and forest degradation in overwintering sites in Mexico all contributed to the steady decline in the abundance of monarch butterflies. Unregulated tourism also has become a threat to the dwindling colonies in Mexico. Protection of overwintering sites in Mexico is crucial to conserve this butterfly in North America. Given the rapid decline of monarch overwintering sites documented here, it is critical to initiate an immediate and concerted effort to protect and restore habitat along the migratory routes in the three countries.
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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 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".