This species is found along forested streams in Antioquia, Tolima, and Caldas Departments on the eastern flank of the Cordillera Central, in Colombia, between 1,100–1,850 m Asl. The type locality is in San Carlos (Lynch and Rueda-Almonacid 1999). Recent surveys have also recorded the species in Tierralta, Cordoba Department, considerably extending its distribution northwards and lowering its altitudinal range to 300 m Asl (Colombia Red List Assessment Workshop August 2016). The EOO for its expanded range is 15,716 km2.
Habitat and Ecology
This is a forest species usually found along the edge of streams that is associated with naturally occurring open areas in primary and secondary forests. Gallery forest cover is needed to keep humidity high, hence, it is very sensitive to any disturbance of its habitat. It breeds by direct development.
It is an uncommon species (Colombia Red List Assessment Workshop August 2016) and is restricted to remnant forest habitat throughout its range, and there is lack of habitat connectivity between known locations attributed to the inhospitable nature of the surrounding agricultural matrix; therefore, it is assumed that the population is severely fragmented (C. Vásquez-Almazán pers. comm. 2014). There is little information on current population trends, but due to the ongoing decline in the quality and extent of its habitat (and EOO), the population is suspected to be decreasing.
The main threat to this species is habitat loss and degradation due to deforestation for agricultural development, mining activities (including pollution), and the planting of illegal crops. In the 2014 assessment, the species was thought to be susceptible to infection by the chytrid fungus, but there is no further direct information on this threat (Colombia Red List Assessment Workshop 2016).
The species occurs in the La Forzosa Reserve and the Ranita Dorada Amphibian Reserve, which was established in 2008 (O. Cortés pers. comm. 2014). The parts of its range outside of protected areas have largely been deforested.
Additional habitat protection and continued enforcement of the protected areas will be important for maintaining critical forest habitat within the range.
Studies on its population size, distribution and trends, and threats are needed.
Red List Status
Listed as Vulnerable because its extent of occurrence (EOO) is 15,716 km2, its population is considered to be severely fragmented, and there is continuing decline in the EOO and the quality of its habitat in the Central Cordillera of the Colombian Andes.
IUCN SSC Amphibian Specialist Group 2017. Pristimantis fallax. The IUCN Red List of Threatened Species 2017: e.T56597A85864450. http://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T56597A85864450.en .Downloaded on 21 January 2019