This species is currently known from sea level to 1,500 m asl east of the Mekong River in eastern Cambodia (Stuart et al. 2006, Poyarkov et al. 2015, Jodi Rowley unpubl. data), southeastern Lao PDR (Dever et al. 2015, Poyarkov et al. 2015), and southern and central Viet Nam including Phu Quoc Island (its only known locality west of the Mekong) and Con Son Island (Inger et al. 1999, Nguyen and Nguyen 2008, Luu et al. 2014, Jodi Rowley unpubl. data). The species' estimated extent of occurrence (EOO) is 408,594 km2, which represents six threat-defined locations.
Habitat and Ecology
This species occurs in relatively dense evergreen and evergreen mixed with deciduous forest in montane, hilly, and lowland areas (Inger et al. 1999, Stuart et al. 2006, Luu et al. 2014, Poyarkov et al. 2015). It is very closely associated with water-filled tree holes, using them for breeding and also as shelter during the day, at least in the breeding season (Stuart et al. 2006, Poyarkov et al. 2015, Jodi Rowley et al. unpubl. data). The species has a relatively long breeding season; reproductive activity has been observed in southern Viet Nam from April to November (Poyarkov et al. 2015). Spawning in the dry season has also been observed after rainfall (Poyarkov et al. 2015). Males call from vegetation adjacent to a tree hole and females deposit eggs on the inner wall, above the water, to where the tadpoles drop upon hatching (Poyarkov et al. 2015). The species appears to reproduce in groups, with one reproductively active male and two to three females in a tree hole together (Poyarkov et al. 2015). Larvae of different stages have also been observed sharing the same tree holes (Poyarkov et al. 2015). Habitat throughout much of this species' range is undergoing a continuing decline in quality and extent due to expanding agriculture (Meyfroidt and Lambin 2008, Sodhi et al. 2009, Meyfroidt et al. 2013, Poyarkov et al. 2015). Some observations of the species have occurred in disturbed areas, including one example where groups were breeding in water-filled barrels in secondary forest (Poyarkov et al. 2015).
The size of this species' population is not well known, however it has been detected in a number of surveys (e.g. Inger et al. 1999, Stuart et al. 2006, Nguyen and Nguyen 2008, Nguyen et al. 2009 Luu et al. 2014, Dever et al. 2015, Poyarkov et al. 2015, Jodi Rowley unpubl. data), and described as potentially locally abundant (Poyarkov et al. 2015). It is likely that ongoing forest loss associated with expanding agriculture throughout much of its range (Meyfroidt and Lambin 2008, Sodhi et al. 2009, Meyfroidt et al. 2013) is causing some population declines. It is possible that some captive populations under the name Theloderma stellatum in Europe and North America (T. Ziegler and J. Holden pers. comm. March 2012), are actually T. vietnamense. Further surveys are needed to determine this species' population trends in the wild.
Habitat loss and degradation due to 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). High rates of deforestation for logging, and agricultural encroachment on natural forest are also ongoing in much of Laos and Cambodia (Bottomley 2000, Sodhi et al. 2009). This species is very likely threatened to some degree by habitat loss, particularly in cases where it involves the removal of trees (and thus its breeding habitat). It may also be threatened by collection from the wild to meet demand, as is the case for similarly attractive frog species from the region (Rowley et al. 2010).
This species is known from many protected areas: in Viet Nam, it occurs in Phu Quoc, Phong Nha - Ke Bang, Cat Tien, Bu Gia Map, Lo Go - Xa Map, Yok Don, and Binh Chau - Phuoc Buu National Parks as well as Nui Ong, Vinh Cuu, Kon Ka Kinh, Kon Cha Rang Nature Reserves and Dong Nai Bioshpere Reserve (Nguyen et al. 2008, Nguyen et al. 2009, Nguyen et al. 1014, Luu et al. 2014, Poyarkov et al. 2015, Jodi Rowley unpubl. data); in Cambodia it occurs in Seima National Biodiversity Conservation Area (Stuart et al. 2006, Jodi Rowley unpubl. data). A large number of other protected areas are included in parts of this species' predicted range; it likely occurs in some of these also.
In order to ensure the species' long-term survival, the lack of data must be addressed; research should be carried out to determine its relative abundance, harvest and threats.
Red List Status
Least Concern (LC)
Listed as Least Concern as this species is relatively widespread, with an estimated extent of occurrence (EOO) of 408,594 km2.
IUCN SSC Amphibian Specialist Group 2016. Theloderma vietnamense. The IUCN Red List of Threatened Species 2016: e.T88137104A88285313. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T88137104A88285313.en .Downloaded on 10 December 2018