This species is endemic to Borneo where it is known from Tawau Hills National Park in Sabah, Malaysia; Gunung Mulu National Park, Penrissen Hills, and Lambir Hills National Park in Sarawak, Malaysia; scattered localities in West, Central, and East Kalimantan Provinces in Indonesia; and Ulu Temburong National Park in Brunei. It is found below 250 m asl. It is likely to occur more widely than currently recorded.
Habitat and Ecology
This species inhabits primary lowland rainforest, where adults live in the leaf-litter and breed in large and small rainwater pools. It will not tolerate habitat disturbance (I. Das pers. comm. March 2018).
As the species is easy to find when it is breeding, it is presumed to be abundant. However, due to ongoing decline in the extent and quality of habitat, the population is suspected to be decreasing.
In Kalimantan, 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, two subpopulations occur in national parks so it is not currently threatened (I. Das pers. comm. March 2018). The area of Gunung Penrissen has a long history of agriculture, especially rice, although rubber and pepper are also grown in all except the steepest terrain (Min et al. 2011). The remaining suitable habitat within its range has almost entirely been converted for recreational use (Gunung Penrissen has been converted into an 18-hole golf course and a 25 acre area of ‘flower garden and theme parks’), or converted to cultivated land, but there is still some suitable habitat available.
It is known from a number of protected areas, including Gunung Mulu and Lambir Hills National Parks (Sarawak); Tawau Hills National Park (Sabah); Ulu Temburong National Park (Brunei); and Gunung Tarak Protected Forest, Bukit Batikap Protected Forest, and Gunung Palung, Bukit Baka Bukit Raya, and Betung Kerihun National Parks (Kalimantan).
Effective preservation of lowland forest is needed to conserve this species because oil palm plantations are encroaching into protected areas in Kalimantan. 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.
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 primary 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. Microhyla perparva. The IUCN Red List of Threatened Species 2018: e.T57888A114919580. http://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T57888A114919580.en .Downloaded on 19 January 2019