This species is known only from a single stream at 2,900 m asl on Mount Fansipan, Hoang Lien National Park, Lao Cai Province, Viet Nam (Nguyen et al. 2013, Rowley et al. 2013). Rowley et al. (2013) estimated that its range may include some of the few small, isolated areas above 2,700 m asl in other parts of the Hoang Lien Son Mountain Range. However, any such area is about 20 km or more away and separated by elevations under 1,000 asl, making the species' dispersal to these parts unlikely. However, it is likely to occur in the very small section of contiguous habitat extending 3 km west of the species' type locality into extreme-eastern Lai Chau Province. The species is very geographically restricted as its extent of occurrence (EOO) is 8 km2, which represents only one threat-defined location.
Habitat and Ecology
This species is known only from the highest peak in Indochina. It is associated with upper montane bamboo or mixed bamboo forest and mainly occurs around rocky streams (Nguyen et al. 2013, Rowley et al. 2013). The climate in this area is characterized by a temperature range of -3°C to 20°C, heavy rainfall, and occasional snow (Rowley et al. 2013). Much remains unknown about this species' life history including its reproduction; however it is expected to deposit eggs and have a free-living aquatic larval stage, as do all other Oreolalax for which the reproductive strategy is known (Fei et al. 1999). Further research is warranted to investigate the species' ecology.
Mount Fansipan has been surveyed relatively extensively compared to the majority of the region (e.g. Ohler et al. 2000, Nguyen et al. 2009, Rowley et al. 2013), however few surveys have detected this species and very little is known about the size and trends of its population except that it has been recorded as locally abundant (J. Rowley pers. comm. 2015). The population is very likely to be in decline due to past and present habitat loss and disturbance.
The most immediate threat to this species' persistence is habitat degradation associated with tourism. Considerable pollution by garbage and runoff from toilets is recorded very close to the streams used by the species (Rowley et al. 2013) and the construction of a cable car from Sa Pa to the summit of Mount Fansipan is likely to affect it (T. Nguyen pers. comm. 2015). The historic burning and subsequent ecosystem conversion of the summit of Mount Fansipan and adjacent areas, which are thought to have been previously covered in forest (Nguyen and Harder 1996), is also likely to have disturbed this species. The species' restriction to high altitudes near the mountain peaks is likely to present an issue as tropical montane forests are expected to be particularly prone to alteration by climate change (Rowley et al. 2013, Foster 2001).
This species is currently only known from Hoang Lien National Park (Nguyen et al. 2013, Rowley et al. 2013).
Strategies for additional protection of habitat within its range may be warranted as habitat degradation caused by tourism continues to be a threat. Further research into the species' ecology, distribution, relative population abundance, and past and current population trends would improve conservation decisions.
Red List Status
Critically Endangered (CR)
Listed as Critically Endangered as this species has an estimated extent of occurrence (EOO) of only 8 km2, is known from one threat-defined location, and is facing a continuing decline in the quality of its habitat.
IUCN SSC Amphibian Specialist Group 2015. Oreolalax sterlingae. The IUCN Red List of Threatened Species 2015: e.T76491633A76491638. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T76491633A76491638.en .Downloaded on 19 January 2019