This species is known only from 1,500 m Asl on Hon Ba Mountain in Hon Ba Nature Reserve, Cam Lam District, Khanh Hoa Province, Viet Nam (Vassilieva et al. 2014). The true range of this species and its elevational limits are unknown. However work in the adjacent and relatively well-studied Phuoc Binh Nature Reserve and Bi Doup-Nui Ba National Park have not revealed its presence, indicating the possibility of low dispersal and endemism to Hon Ba Mountain. As such, the species' estimated extent of occurrence (EOO) is 14 km2 and its range is thought to represent only one threat-defined location, from which dispersal is probably not likely; thus the species is very restricted geographically.
Habitat and Ecology
This species occurs in high-altitude wet mixed evergreen forest (Vassilieva et al. 2014). Much of its life history remains unknown, including its reproductive biology and habitat use, however Vassilieva et al. (2014) interpret the absence of open ponds in its habitat as evidence that this species may be a phytotelm breeder. The species is presumably oviparous with an aquatic, free-living larval stage, as are other Kalophrynus for which the reproductive strategy is known.
Very little is known about the size and trends of this species' population except that the only individuals to have been recorded are the type-specimens (two adult males) (Vassilieva et al. 2014). Further surveys are needed to determine its relative abundance and population trend.
Habitat loss and degradation, particularly as a result of the conversion of forest to agricultural land to grow cash crop plantations (eg. rubber, coffee and tea), is an ongoing threat throughout the Central Highlands of Viet Nam (Meyfroidt and Lambin 2008, Meyfroidt et al. 2013). It is uncertain exactly how this threat affects Kalophrynus honbaensis, however the species' small range makes it vulnerable to the effects of deforestation. Further research is needed to determine the threats affecting this species.
It is known to occur in Hon Ba Nature Reserve.
Effective protection of forest habitat within the Hon Ba Nature Reserve and on Hon Ba Mountain are measures that could protect this species.
In order to ensure the species' long-term survival, the lack of data must be addressed; research should be carried out to determine its distribution, relative abundance, life history, and threats.
Red List Status
Listed as Vulnerable as this species is currently thought to be from only one very small threat-defined location on Hon Ba Mountain that may be threatened by habitat degradation and could result in rapid population declines.
IUCN SSC Amphibian Specialist Group 2017. Kalophrynus honbaensis. The IUCN Red List of Threatened Species 2017: e.T73726664A73726671. http://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T73726664A73726671.en .Downloaded on 24 February 2019