Abundance and microhabitat use of the Endangered toad Rhinella yanachaga (Anura: Bufonidae) in the cloud forest of Yanachaga Chemillen National Park, Peru

The arboreal toad Rhinella yanachaga is an endemic species of the cloud forest of central Peru, and is categorized as Endangered according to the International Union for Conservation of Nature. The core habitat of this species is within the Yanachaga-Chemillén National Park, but the status of its populations remains unknown. Obtaining quantitative data based on field surveys is essential for conserving this species in the park. In this study, the abundance, size, and microhabitat use of R. yanachaga were examined across an elevational gradient. Individuals with snout-to-vent length (SVL) > 20 mm were sampled in four transects between 2,400 and 2,800 m, in the wet and dry seasons. Using night surveys, individual data were recorded on sex, SVL, microhabitat, geographic location, relative humidity, and temperature. The abundance of females and males varied among transects in dry and wet sampling periods. We recorded more individuals in the dry season and observed that frogs distributed at higher elevations tend to have a larger body size than those at lower elevations. Most individuals appear to prefer microhabitats composed of leaves and ferns. Additionally, we observed sexual dimorphism in size, as females were larger than males. These findings contribute to amphibian conservation programs in Peru.