Dispersal barriers and climate determine the geographic distribution of the helicopter damselfly <i>Mecistogaster modesta</i>
Bibliographic record
Abstract
Abstract Species’ ranges are typically constrained by the interplay of physical barriers to dispersal, environmental requirements such as suitable climatic conditions and biotic constraints such as from predation or competition. However, teasing apart the relative importance of these constraints in determining species distributions still represents a major challenge for ecologists. The Neotropical damselfly Mecistogaster modesta (Coenagrionidae: Odonata) inhabits wet and moist forests in mainland Central America and north‐western South America. This habitat specialist spends its larval development exclusively in tank bromeliads, where it acts as a keystone predator within the aquatic food web. Although tank‐forming bromeliads occur from the southern United States throughout most of South America, M. modesta is absent from the Caribbean islands and South America south‐east of the Andes mountain chain. We employed species distribution models to explore the relative importance of physical barriers (Andes mountain range and oceanic barriers), climate (mean annual temperature and annual precipitation) and biotic interactions (competition from other bromeliad‐dwelling odonates) in limiting the geographic distribution of M. modesta . We found that dispersal barriers strongly limit the geographic distribution of M. modesta . In addition, its range is restricted by low temperatures and low precipitation. Competition from other bromeliad‐dwelling odonates was not important in limiting the damselfly's range. Because of the physical barriers to dispersal, M. modesta does not occupy its full potential geographic range. Specifically, our model predicted suitable habitat on the Caribbean islands and throughout most of South America, where the species is currently absent. These findings have important conservation implications, particularly as the aridification of rainforests and subsequent localised extinctions due to climate change continue. On the other hand, the species may respond to warming temperatures by tracking climate to higher elevations, with subsequent effects on naïve high‐elevation bromeliad food webs. An upwards migration could also increase the probability of M. modesta overcoming the dispersal barrier presented by the Andes, enabling the damselfly to invade large areas of suitable habitat in South America.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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 teacher head, 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".