This species is known with certainty only from approximately 1,500-2,000 m asl in Lam Dong Province, southern-central Viet Nam (Smith 1921, Orlov et al. 2002, Nguyen et al. 2009). These may not represent the actual limits of the species' range as similar habitat and elevations to those in its known localities extent to adjacent areas of the Langbian Plateau. Further surveys there may serve to expand its known range, though none have since the species' original description in 1921 (Smith 1921).
Records of the species in Tam Dao, northern Viet Nam (Inger et al. 1999), and Chanthaburi Province, Thailand (Chan-ard 2003), refer to populations of Odorrana nasica and Hylarana faber, respectively (Bryan Stuart pers. comm. December 2015), and are herein excluded. There is also a record of the species from Gia Lai Province in Viet Nam, however given the biogeography this area (the Kon Tum Plateau), an isolated observation on its southern edge appears unlikely (Jodi Rowley pers. comm. December 2015); this record is probably assignable to Odorrana absita (Bryan Stuart pers. comm. December 2015) and thus is also excluded. This species' estimated extent of occurrence (EOO) is 3,139 km2, which consists of four threat-defined locations.
Habitat and Ecology
This species is associated with forest and has mostly been observed adjacent to streams (Le 2011). It reproduces in the dry season and breeding appears to be concentrated around December and January (Le 2011). The species is an explosive breeder; aggregations of up to 100 individuals have been observed during the breeding season (Le 2011). Amplexus normally occurs on leaf littler adjacent to streams, and large egg clutches are deposited directly into the water (Le 2011, Rowley et al. 2012). Much of the habitat throughout this species' range is degraded by ongoing forest loss associated with agriculture and aquaculture (Stuart 2005, Meyfroidt and Lambin 2008, Sodhi et al. 2009, Le 2011, Meyfroidt et al. 2013) and it has been observed breeding in moderately to highly disturbed habitats (Le 2011).
Very little is known about the size of this species' population except that it has been detected in a number of surveys since its description (Smith 1921, Le 2011, Jodi Rowley unpubl. data). It was described as common on the Langbian Plateau (Smith 1921), has been recorded in large numbers since during the breeding season, when it harvested by the local people for food (Le 2011). This species' population is likely in decline due to forest clearing for agricultural practices that are ongoing throughout parts of its range (Meyfroidt and Lambin 2008, Sodhi et al. 2009, Meyfroidt et al. 2013).
Habitat loss and degradation due to the effects of rapidly expanding agriculture is an ongoing threat to biodiversity throughout Southeast Asia (Sodhi et al. 2009). In the Central Highlands of Viet Nam large areas of forest are converted to agricultural land to grow cash crop plantations (e.g. rubber, coffee and tea) (Meyfroidt and Lambin 2008, Meyfroidt et al. 2013). Known breeding sites of this species are moderately to heavily disturbed by fishing practices and aquaculture; the forest and stream at one site in particular has been severely degraded by an adjacent salmon farm (Le 2011). Therefore this species is likely threatened to some extent by habitat loss. In addition, considerable numbers of this species are harvested during the breeding season for use as a food source (Le Thi Thuy Duong pers. comm. March 2012) which, combined with habitat loss, may be affecting its population.
This species is known from Bidoup-Nui Ba National Park (Le 2011), and its predicted range includes parts of a number of other protected areas including Phuoc Binh Nature Reserve; it very likely occurs in some of these also.
Addressing the lack of data is the first step towards ensuring this species' long-term persistence.
Further research on its taxonomy, true distribution, effects of harvest, and the size and trends of its population would inform conservation decisions.
Red List Status
Listed as Endangered as this species has an estimated extent of occurrence (EOO) of only 3,139 km2, occurs in only four threat-defined locations, and is facing a continuing decline in the quality of parts of its habitat.
IUCN SSC Amphibian Specialist Group 2016. Hylarana montivaga. The IUCN Red List of Threatened Species 2016: e.T58672A55070277. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T58672A55070277.en .Downloaded on 18 November 2018