The study focused on three municipalities in southwestern Cundinamarca: Tibacuy, Nilo, and Viotá. Situated between 645 and 1840 meters in elevation, this region includes low-montane rainforest and low-montane dry forest zones under Holdridge’s life zone classification. The landscape is a mosaic of secondary Andean forest, shaded coffee crops, and open areas used for livestock farming. Researchers surveyed three habitat types: secondary forest with advanced vegetation structure, shaded coffee crops with varying management intensity, and pasture-dominated open areas with sparse or no tree cover. These categories represent a gradient of habitat transformation from less disturbed to highly modified environments.

Field surveys were conducted in two periods: between 2015 and 2019, and between June 2021 and July 2022, covering both rainy and dry seasons. The researchers employed time-constrained Visual Encounter Surveys, a standard protocol for amphibian and reptile inventories. Each sampling unit consisted of a four-hour search conducted by five observers, performed during both diurnal and nocturnal activity periods. Surveys covered representative microhabitats including vegetation, leaf litter, streams, and ponds, up to a maximum height of five meters above ground. In total, 53 sampling events were conducted across the study area, corresponding to a sampling effort of 1060 person-hours. Effort was broadly comparable across habitats, with 500 person-hours in forest, 340 in crops, and 220 in open areas.

The surveys recorded a total of 57 species and 608 individuals, including 391 amphibians and 217 reptiles. The most abundant amphibians were Boana platanera, Engystomops pustulosus, and Pristimantis taeniatus. Among reptiles, the most abundant were Gonatodes albogularis, Cnemidophorus lemniscatus, and Hemidactylus frenatus. Species richness varied sharply among habitat types: forest supported the highest richness with 45 species, followed by open areas with 34, while coffee crops hosted only 14. Forests also contained the greatest number of individuals, with 225 records, followed by open areas with 207 and coffee crops with 176.

To ensure that these patterns were robust rather than artifacts of uneven sampling, the researchers assessed sampling completeness using coverage-based rarefaction and extrapolation analyses based on Hill numbers. Sample coverage exceeded 95% for both taxonomic groups, and rarefaction curves approached asymptotic levels, with amphibians reaching asymptotes at lower sample sizes than reptiles. Spatial autocorrelation analysis using Moran’s I revealed no significant spatial structure in species richness across sampling localities, indicating that observed richness patterns were not spatially structured. This absence of spatial autocorrelation strengthens the interpretation that habitat type, rather than geographic proximity, drives the community patterns documented here.

Coverage-based diversity analyses revealed consistent habitat-driven patterns for both amphibians and reptiles. Amphibians exhibited the highest species richness, Shannon diversity, and Simpson diversity in forest, with reduced diversity in crops and open areas across all Hill numbers. Reptiles showed a similar gradient, with forests supporting the highest diversity, though overall richness and effective diversity values were lower than those observed for amphibians. Interestingly, the nature of the response differed between groups: amphibians showed a stronger decline in species richness, whereas reptiles displayed more pronounced changes in community structure related to species dominance. These patterns suggest that habitat transformation impacts different components of diversity in each taxonomic group.

Rank-abundance distributions exposed stark differences in community structure among habitats. Forest assemblages showed longer tails in rank distributions, with a greater number of low-abundance species and a more gradual decline in abundance, reflecting higher evenness. In contrast, coffee crops and open areas were characterized by fewer species and stronger dominance by a small subset of taxa. Dominant amphibians varied among habitats, including Engystomops pustulosus, Boana platanera, and Pristimantis species. Dominant reptiles in open areas included Cnemidophorus lemniscatus, Gonatodes albogularis, and Hemidactylus frenatus, whereas forest sites contained a broader distribution of species with lower individual abundances. These patterns are consistent with environmental filtering processes, where habitat transformation selectively favors disturbance-tolerant generalists while restricting taxa with more specialized ecological requirements.

The contrasting responses of amphibians and reptiles likely reflect fundamental differences in physiological constraints and ecological strategies. Amphibians, with their permeable skin, dependence on moisture for reproduction, and narrow thermal tolerances, are generally more sensitive to environmental changes. Their stronger association with forest habitats is likely due to their dependence on humid and thermally stable microclimates, which reduce the risk of desiccation and support reproductive success. Reptiles, by contrast, typically exhibit broader tolerance to thermal and hydric variation, enabling them to persist or even increase in abundance in disturbed environments. This physiological flexibility explains their broader habitat occupancy and higher representation in transformed landscapes.

Beyond the field surveys, the researchers compiled a comprehensive regional inventory based on field data, biological collections, and biodiversity databases, documenting 86 species of herpetofauna in the study region. Among amphibians, the order Anura was the richest group with 32 of 35 species recorded, with Hylidae as the most speciose family followed by Strabomantidae and Dendrobatidae. Regarding reptiles, 51 species have been recorded, primarily represented by the order Squamata, with Colubridae as the most diverse family. Notably, two invasive species were documented: the North American bullfrog Aquarana catesbeiana and the South Asian house gecko Hemidactylus frenatus. The presence of potentially undescribed or poorly characterized taxa, including an Anolis species requiring further integrative taxonomic analyses, highlights the still incomplete knowledge of herpetofauna diversity in the Colombian Andes.

The implications of this study extend far beyond southwestern Cundinamarca. The tropical Andes are recognized as a global biodiversity hotspot, characterized by exceptional levels of endemism and a high concentration of threatened species. In Colombia, the Andean region harbors approximately 53% of the country’s total herpetofauna, including a high number of endemic species, yet a substantial proportion of these species occurs outside protected areas. The patterns documented here suggest that continued habitat loss is likely to disproportionately affect taxa with specialized ecological requirements, potentially leading to biotic homogenization and changes in ecosystem functioning. The researchers emphasize that conservation strategies should prioritize the protection of remaining forest patches, the maintenance of ecological connectivity, and the implementation of land-use practices that promote structurally heterogeneous landscapes. While shaded coffee crops hosted several species also present in forest habitats and may function as secondary habitats or dispersal matrices, these environments do not replace forest ecosystems, as they primarily support disturbance-tolerant species and retain only a subset of the regional fauna. Long-term monitoring programs will be essential to evaluate how ongoing environmental changes, including land-use transformation and climate change, affect the distribution and persistence of amphibian and reptile assemblages in Andean ecosystems.

Subject of Research: Community ecology and conservation of amphibians and reptiles across a habitat transformation gradient in the Colombian Andes

Article Title: Habitat transformation reshapes diversity and community structure of amphibians and reptiles in the Eastern Andes

Article References: Falcón-Espitia, N., Ríos-Orjuela, J. C., Perez-Rojas, S., Plazas-Cardona, D., & Arias-Escobar, A. (2026). Habitat transformation reshapes diversity and community structure of amphibians and reptiles in the Eastern Andes. Herpetozoa, 39, 239-252. https://doi.org/10.3897/herpetozoa.39.e171614

Image Credits: AI Generated

DOI: 10.3897/herpetozoa.39.e171614

Keywords: amphibians, reptiles, Colombian Andes, habitat transformation, biodiversity, environmental filtering, community structure, Cundinamarca, Herpetozoa, Habitat, transformation, reshapes