This species was previously only known from the vicinity of the type locality: Abra Acjanacu, a high pass in the Cordillera de Paucartambo, which is the easternmost Andean range facing the Amazonian lowlands in the region of Cusco, Peru (De la Riva et al. 2008). However, it is now found throughout the high elevation grasslands of Manu National Park (A. Catenazzi pers. comm. April 2017). It is likely to occur further to the north and south of its known distribution, however the areas have not been surveyed as of yet (A. Catenazzi pers. comm. April 2017). It occurs at elevations between 2,800–3,600 m asl. It occurs in two threat defined locations and the extent of occurrence (EOO) of its current known range is 69 km2.
Habitat and Ecology
It is restricted to Andean wet puna and the transitional areas to montane, cloud forest, and may be found at the edges of agricultural land, but not in cultivated areas. Individuals are commonly found within bunch grasses, under mosses, and under rocks in humid puna (De la Riva et al. 2008). It breeds by direct development.
It is common within Manu National Park and in suitable habitats outside of the park (A. Catenazzi pers. comm. October 2017). During surveys conducted in 2007, 51 individuals were observed over 25 person-days, while 34 individuals were detected over 32 person-days in 2008 (von May et al. 2008). Surveys in 1996-1999, 2008-2009, and 2012-2016 have recorded this species, and have found in to be abundant and increasing in subpopulations (A. Catenazzi pers. comm. April 2017). The population is considered to be stable.
Intentional burning of grasslands and agricultural activities, specifically cultivation of potatoes, occur outside of Manu National Park within the species' distribution (A. Catenazzi pers. comm. April 2017). While these activities are contributing to general habitat loss within its range, they are not thought to be causing population declines.
While chytridiomycosis is the probable cause of severe population declines in amphibian assemblages of the upper Manu National Park (Catenazzi et al. 2011), this species is not likely to be affected by chytrid (A. Catenazzi pers. comm. April 2017). When exposed to high levels of zoospores in an experimental infection study, no mortality occurred in this species (Catenazzi et al. 2017).
This is present in Parque Nacional Manu, in which the habitat is well protected. The land adjacent to the western side of the park is now also protected by the locals, reducing the threat of grassland fires invading Manu National Park, creating a buffer zone known as ACP Pilco Grande (A. Catenazzi pers. comm. April 2017). It is listed as Endangered (EN) in Peru according to the Categorization in Endangered Species of Wild Fauna (Decreto Supremo Nº004-2014-MINAGRI).
This species would likely benefit from improved habitat protection at sites where it is known to occur.
Further surveys are required to determine the full distribution of this species.
Red List Status
Listed as Near Threatened because its extent of occurrence (EOO) is 69 km2 and it occurs in two threat-defined locations, thus making the species close to qualifying for Vulnerable, however it is common and expected to occur more widely, most of its known habitat is included in a well-protected area and does not appear to be threatened, and the population is considered to be stable.
Subpopulations previously assessed as Noblella peruviana in fact pertain to Psychrophrynella usurpator.
IUCN SSC Amphibian Specialist Group 2018. Psychrophrynella usurpator. The IUCN Red List of Threatened Species 2018: e.T57225A3057260. http://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T57225A3057260.en .Downloaded on 24 January 2019