Edge effects on amphibians in transformed tropical dry forest landscapes: The relationship between functional and taxonomic diversity

The tropical dry forest (TDF) is one of the ecosystems most severely affected by deforestation globally. The remaining fragments are exposed to edge effects that significantly alter abiotic conditions, influencing species distribution and ecological dynamics. Despite this, the impact of edge effects on the taxonomic and functional diversity of amphibians in TDF fragments remains poorly understood. This study assessed edge effects on the taxonomic and functional diversity of anuran assemblages in the Colombian Caribbean, considering environmental and vegetation structural variables. A total of 108 transects were surveyed along a gradient from pastureland to the native forest. Three functional traits—snout-vent length, body temperature, and habit—were analyzed. The survey recorded 15 species, with higher abundance and species richness found at forest edges and adjacent pastures. In contrast, the forest interior showed lower evenness and higher dominance. Two species were exclusive to the forest interior, with an additional two identified as core-area specialists. Taxonomic diversity indices were strongly correlated with litter and understory characteristics. Functional evenness was highest in the forest interior, indicating a more uniform distribution of functional traits in these areas. In contrast, elevation influenced functional diversity indices. These results highlight distinct ecological mechanisms shaping assemblages: specialized species adapted to stable, homogeneous conditions dominating the forest interior. At the same time, edges and pastures favor species that are tolerant of extreme environmental conditions through environmental filtering. This study emphasizes the critical importance of conserving the forest interior and managing edge environments to sustain functional diversity and enhance the resilience of TDF.