Conservation Value:

The Sierra Nevada de Santa Marta (SNSM), classified as a Key Biodiversity Area, appears to be the only place in the Americas with stable populations of high-altitude harlequin toads — the world's most threatened genus of amphibians.  The SNSM is home to 5 threatened endemic Atelopus species, including the Critically Endangered Starry Night toad (Atelopus arsyecue) and the Endangered Santa Marta harlequin toad (Atelopus laetissimus).  It is also home to 17 other endemic species of amphibians and at least 2 more species of Atelopus that are in the process of being described.  The reasons these stable populations of high-altitude harlequin toads occur here are largely unknown.

Reaching 5,775 m, SNSM is the highest coastal mountain in the world.  Its elevational amplitude, isolation, and tropical location have conferred biological and hydrological importance. SNSM ecosystems encompass tropical dry forests (one of the most threatened ecosystems in the Neotropics), montane forests and páramos that supply drinking water to two million people in the departments (provinces) of Magdalena, Cesar, and La Guajira.

Threats:

Disease transmission by the Batrachochytrium dendrobatidis (Bd) fungus and habitat degradation due to livestock and agricultural activities, water pollution, and unsustainable tourism practices are the main drivers behind the extinction or endangerment of many harlequin toads (81% of Atelopus species are classified as Endangered or Critically Endangered).

Actions & Results:

Key actions are to assess and monitor the population dynamics and threats to endemic species of harlequin toads, and to design and develop conservation strategies with local communities.  In 2024, ICFC's partner Fundación Atelopus conducted expeditions in San Pedro de la Sierra (4) and the indigenous community of Sogrome (4), to collect demographic data on the Santa Marta harlequin toad and the Starry Night toad.  A total of 132 individuals of the Santa Marta harlequin toad were recorded in San Pedro and 115 individuals of the Starry Night toad were recorded in Sogrome.  The data and subsequent analysis showed that the populations are stable, with high survival rates among individuals.  However, low recruitment rates were also observed, indicating that few individuals are reproducing and/or joining the populations.  In addition, the presence of the Bd fungus was recorded for the first time in three specimens of the Starry Night toad. Genetic analyses also revealed extreme inbreeding in both populations, with very low effective population sizes.  All in all, the equilibrium of these Atelopus populations in the SNSM can be considered ‘fragile’, as a single natural or stochastic / anthropogenic event could severely impact the populations.  Lastly, these expeditions have facilitated deeper collaboration with rural and Indigenous communities, including: the establishment of a community ecological monitoring group involving youth; organization of ‘bioblitz’ to quickly survey the native species of the SNSM and to promote community participation through environmental education; and, installation of camera traps to document the presence/absence of wildlife in areas adjacent to restoration (agroforestry) patches in farms around the town of San Pedro de la Sierra.