This species is known from montane regions between 400-1,700 m asl across Viet Nam from Binh Thuan Province as far north as Nghe An Privince (Nguyen et al. 2009 (reported as R. calcaneus), Orlov et al. 2012, J.J.L. Rowley, pers. comm. July 2014). Habitat contiguous with one of the species' localities extends into Bolikhamxai and Khammouan Provinces, eastern Lao PDR. Further surveys in these areas may also uncover this species' presence there, so its range has been projected beyond known sites to include these areas of suitable habitat. The species' estimated extent of occurrence (EOO) is 193,843 km2, which represents six threat-defined locations because the species is known from six relatively separate areas affected by habitat loss.
Habitat and Ecology
This species is associated with montane streams in dense evergreen forest (Orlov et al. 2012). It appears to breed periodically, and is most reproductively active in March-June and October-November, particularly during and after rainfall. Males call diurnally, however amplexus occurs only after nightfall. The pair construct a foam nest in leaves hanging near water and 100-500 eggs are deposited in the nest. Upon hatching, the larvae collapse the nest, fall to the ground, and then then flow into the water. Tadpoles have been observed in July in the pools of small (<3 m) to large (>10 m) streams (Orlov et al. 2012).
The population size is currently unknown, other than that it has been observed in groups of 5-6 calling males during the breeding season (Orlov et al. 2012). Populations of this species may be decreasing due to habitat loss associated with agriculture.
Widespread deforestation is known to occur in the regions where this species is distributed, so habitat loss is most likely a threat (N. Poyarkov pers. comm. October 2014). In Kon Tum and Gia Lai provinces, forest encroachment by agricultural plantations (rubber, coffee, cassava and corn) is likely to be a major threat to the habitat of this species ( T. Nguyen pers. comm. Jan 2015).
This species is known from several protected areas: A Yun Pa Proposed Nature Reserve, Kon Cha Rang Nature Reserve, Kon Ka Kinh National Park, Ngoch Linh Nature Reserve (in both Quang Nam and Kon Tum provinces), Ba Na-Nui Chua Nature Reserve, Nui Ong Nature Reserve, and Bach Ma National Park.
Addressing the lack of data is the first step towards ensuring this species' long-term survival; further research on its abundance, range, and threats would inform conservation decisions.
Red List Status
Least Concern (LC)
Listed as Least Concern because the species is relatively widespread (extent of occurrence (EOO) of 193,843 km2) and it occurs in six protected areas.
In the Rhacophorus calcaneus group of Orlov et al. (2012). Confused with Rhacophorus calcaneus prior to its naming by Inger et al. (1999). The original publication noted the following localities (originally as Rhacophorus calcaneus) as doubtful: Tam Dao, Vinh Phuc and Huong Son, Ha Tinh (likely based on Rhacophorus orlovi); Chu Yang Sin, Dak Lake and Bidoup, Lac Duong, Lam Dong (likely based on Rhacophorus vampyrus); Da Teh, Lam Dong (likely confused with Rhacophorus rhodopus) (Frost 2013).
IUCN SSC Amphibian Specialist Group 2016. Rhacophorus robertingeri. The IUCN Red List of Threatened Species 2016: e.T48103096A48103103. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T48103096A48103103.en .Downloaded on 10 December 2018