One-year Sierra Chiquita survey links butterfly communities to vegetation, elevation and season

A one-year observational survey in Mexico’s Sierra Chiquita recorded 195 butterfly species and found that abundance, species richness, diversity and community composition varied across seven vegetation types along an elevation gradient. The study was a systematic field survey, not an experiment, so its environmental results describe associations rather than establishing causes. The survey covered seven sites in four localities within the Sierra Chiquita, an isolated orographic unit in the coastal plain of the Gulf of Mexico.

The sites ranged from 460 to 1,080 metres above sea level and supported thorn forest, Tamaulipan thornscrub, submontane scrub, gallery forest, oak and pine forest, oak forest and cloud forest. The region is designated a Mexican Priority Region for Conservation of Biodiversity and marks the boreal limit of cloud forest in northeastern Mexico. Researchers randomly placed six 10-metre-radius plots within each vegetation type using geographic information system software.

From November 2015 through October 2016, they visited each plot monthly, recorded adult butterflies during 20-minute counts and collected specimens with entomological nets. Environmental measurements were made concurrently with a portable weather station, digital luxmeter and spherical densiometer. The inventory comprised 38,011 specimens from six families, 20 subfamilies, 38 tribes, 129 genera and 195 species.

Nymphalidae accounted for 41% of individuals and 33% of species. A sample-coverage estimator rated the overall inventory as 99.8% complete, meaning that nearly all species detectable by the study’s sampling approach were recorded, although the authors noted that some species could remain unregistered. Submontane scrub at 550 metres produced the highest recorded abundance and richness, with 6,362 individuals and 140 species, as well as the highest diversity values.

Cloud forest at 1,080 metres had 4,140 individuals and 88 species. Abundance, richness and Simpson diversity generally decreased with increasing elevation and differed significantly among sites, apart from comparisons between thorn forest and gallery forest. A one-way PERMANOVA also detected differences in species composition among the sites except for that same pair, while non-metric multidimensional scaling separated the vegetation communities.

Seasonal differences were most apparent in abundance. The rainy season, defined as May through October, had the highest abundance and observed richness, and abundance differed significantly between seasons at every site except in the thorn-forest versus gallery-forest comparison. Diversity indices did not differ significantly between seasons.

A two-way PERMANOVA detected significant effects of season (F = 9.287, df = 1, p < 0.001) and plant community (F = 45.91, df = 6, p < 0.001) on species composition, but the interaction between them was not significant. Canonical correspondence analysis identified five measured variables as significantly associated with butterfly communities: heat index, dew point, solar radiation, canopy leaf area and the number of flowering plants, each at p < 0.05. Solar radiation, canopy leaf area and flowering-plant number were most closely related to the first ordination axis, while heat index and dew point were most closely related to the second.

The species-level analysis associated different butterflies with different combinations of these conditions and vegetation types, but the design cannot establish that the measured variables caused the observed distributions. The analysis has several bounded limitations. Elevation and vegetation composition changed together, so their separate effects could not be isolated.

The environmental analysis included ten microhabitat variables but did not directly assess host-plant relationships, limiting interpretation of how particular species used plants for feeding, oviposition or shelter. Within those limits, the study provides a near-complete baseline inventory for a priority conservation region. The authors described the results as reference data for regional and national comparisons and as an initial step toward evaluating whether butterflies could be used as a biodiversity-indicator group in Mexico.

Subject of Research: Observational assessment of butterfly community composition across vegetation and elevation gradients in Sierra Chiquita, Mexico

Article Title: Butterfly community composition along a vegetation gradient in the Sierra Chiquita, Mexico

Article References: Meléndez-Jaramillo, E., Sánchez-Castillo, L., Coronado-Blanco, J. M., Segura-Martínez, M. T. D. J., & Cantú-Ayala, C. M. (2024). Butterfly community composition along a vegetation gradient in the Sierra Chiquita, Mexico. Neotropical Biology and Conservation, 19(4), 449-474. https://doi.org/10.3897/neotropical.19.e136190

Image Credits: AI Generated

DOI: 10.3897/neotropical.19.e136190

Keywords: butterflies, Sierra Chiquita, Mexico, elevation gradient, vegetation communities, species richness, seasonal variation, biodiversity, environmental associations, Butterfly, community, composition