[1] Recent variation in air temperature, precipitation, stream flow patterns, and the subsequent spread of a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) linked to global climate change have been the leading cause of decline for A.

Suitable habitat includes both pre-montane and lower-montane zones as well as some lowland sites along rocky streams in hilly areas (ranging from 6 to 2,000 metres or 20 to 6,562 feet in elevation).

[1] In Panama, mass mortality has drastically reduced populations of A. varius in recent years and it was believed to be locally extinct,[11] however the species was recorded again in the 2019 assessment.

A trend toward rising temperatures across the tropics in the late 1980s and early 1990s has been implicated in the declines of multiple lizard and amphibian species including several Atelopus spp.

[4] This pathogen can be transmitted between individuals through shed skin cells and is known to infect keratinized body surfaces where it can impair cutaneous respiration and osmoregulation thus resulting in mortality.