This species has been recorded on the Volcán Barva, Cordillera Central, Costa Rica, at 2,000–2,200 m asl (Savage 2002). The known historical range is less than 100 km²
Habitat and Ecology
This species lives in montane rainforest. It is a fossorial species, and can be found under surface debris within the forest during periods of heavy rain, but otherwise it prefers mossy stream banks during dry periods. It is an explosive breeder that lays its eggs in forest floor pools, as well as in man-made drainage ditches (Savage 2002).
It was formerly common in appropriate habitat and during the breeding season at the onset of the rainy season (2,765 males were seen visiting two pools in an eight-day period; Nowak and Robinson 1975). This species was not seen from 1987–2007 despite repeated searching (seven consecutive years of intensive searching to 2007: Héctor Zumbado, Andrés Vaughn, Warren Calvo, Adrián García unpublished data 2007) throughout its range. Nevertheless, the species was subsequently rediscovered in 2009 at two sites 2 km apart with adults, juveniles, and tadpoles
Although not proven, the main cause of the population decline is thought to be chytridiomycosis perhaps in synergy with the effects of climate change. The current reversion of the pastures where the species was original found abundantly to secondary forest may or may not be a threat to this species (Abarca et al. 2010).
Much of the known range of this species is protected in Parque Nacional Braulio Carrillo, 20 km north-east of the capital of San José. The two sites where the species is known to persist in 2010 are located in the Cerro Dantos and Jaguarundi Refuges, neither of which have the same protection status as a national park. Even with the lower protection status, the forest cover of these refuges remains intact and seemingly not threatened (Bruce Young pers. obs. 2011). More information is needed on this species' natural history and threats.
NatureServe & IUCN SSC Amphibian Specialist Group, 2012. Incilius holdridgei. In: IUCN 2014