This species is widely distributed throughout much of the remaining lowland forest of Borneo, below 300 m asl. It is likely to occur more widely than currently recorded.
Habitat and Ecology
This is a lowland, tropical moist primary and old secondary forest species. It is not found in modified habitats. Males have been found calling at the entrance of burrows. It is presumed to breed in small pools of standing water on the forest floor.
It is relatively abundant where it occurs in some localities. In Sarawak, only one or two individuals are found at a time and it is not considered to be abundant (I. Das pers. comm. March 2018). Due to ongoing decline in the extent and quality of habitat, the population is suspected to be decreasing.
The principal threat to the species is rapid clear-cutting of lowland tropical rainforest in forest concession land and for oil palm plantations (Indonesia Red List Assessment Workshop May 2017). In Sarawak, the lowland forest range of this species outside of protected areas is threatened by logging concessions, small scale subsistence logging and oil palm plantations (I. Das and Y.M. Pui pers. comm. March 2018).
This species has been recorded from Lanjak Entimau Wildlife Sanctuary (Sarawak), Tawau Hills Park and Danum Valley Conservation Area (Sabah), and Kayang Mentarang National Park (Kalimantan). It probably also occurs in Crocker Range in Sabah.
Effective preservation of lowland forest is needed to conserve this species because oil palm plantations are encroaching into protected areas. Some oil palm companies and forestry companies designate High Conservation Value areas, which is required by some financial institutions providing loans. However, not all lenders require these areas to be set aside and the habitat within the HCVs could disappear if the lender or requirements change (Indonesia Red List Assessment Workshop May 2017).
Further work is required to improve the understanding of the species' population size, distribution and trends. Taxonomic work is also required to be done on the whole genus to provide improved information for the reliable identification of these species (I. Das pers. comm. March 2018).
Red List Status
Near Threatened (NT)
Listed as Least Concern in view of its wide distribution and presumed large population. However, since this species depends on temporary pools within primary and old secondary growth lowland forest and there is ongoing decline in the extent and quality of these habitats due to widespread forest loss within its range, its population should be monitored.
IUCN SSC Amphibian Specialist Group 2018. Kalophrynus subterrestris. The IUCN Red List of Threatened Species 2018: e.T57847A114919398. http://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T57847A114919398.en .Downloaded on 18 November 2018