Abstract

Atelopus laetissimus is a bufonid toad that inhabits the mountainous areas of the Sierra Nevada de Santa Marta (SNSM), Colombia. This species is endemic and endangered, so information about its ecology and distribution are crucial for the conservation of this toad. Here, the relative abundance, habitat and microhabitat uses, and vocalization of A. laetissimus are described from the San Lorenzo creek in the SNSM, as well as its potential distribution in the SNSM. To this end, 447 individuals were analyzed during several sampling trips from 2010 to 2012. Against expectations, population density was significantly higher in the stream than in the riparian forest. Overall, A. laetissimus used seven different diurnal microhabitats, with a high preference for leaf litter substrates and rocks. The rate of recaptures decreased linearly across the survey nights. Two types of vocalizations related to the advertisement call of A. latissimus were recorded: a series of pulsed calls like a buzz and another short call, lacking pulses or partially pulsed. According to this analysis, the areas with higher habitat suitability for A. laetissimus were located principally in the northern and northwestern regions of the SNSM, in agreement with literature. Moreover, the data modeling indicated a significant increase in habitat loss from 2013 to 2017. The information presented here should be considered as a starting point for the conservation of this species.