This species is found from Myanmar (Kyaik Ti Yo National Park in Mon State), through western Thailand (Tenasserim) and Malaysia (including Penang and Tioman) to Indonesia (Sumatra, Java, Kepulanuan Riau Islands, Kalimantan, Natuna Besar and southwest Sulawesi, where it is introduced) and Borneo (Brunei Darussalam and Malaysian Borneo). It is absent from Singapore and Phuket. It occurs from lowlands up to 1,200 m asl (and up to 1,400 m asl in Sumatra).
Habitat and Ecology
In Borneo it is apparently confined to the banks of rainforest streams and rivers throughout its life cycle and has been recorded only from heavily forested areas. It has not been reported from disturbed or heavily logged forests. Its larvae live on the bottom of riffles and rapids. In Sumatra and Java it is found in rivers or along small streams in various habitats, from primary rainforest to degraded areas and even near cities. On these islands, the species can tolerate a considerable amount of pollution and is still abundant where other species have disappeared.
Its abundance throughout its range varies greatly. It can be present and abundant, present but uncommon, or absent from forests that appear roughly the same.
In Borneo the destruction of large portions of the lowland forests and the reduction of remaining forests into fragmented mosaic are the principal threats. On Borneo, deforestation has an immediate impact on larval development through the siltation of streams. However, in some other places (especially Java) it breeds in polluted rivers in cities.
It occurs in many protected areas. In Borneo the protection of large areas of rainforest in Kalimantan and Sarawak is needed. In Peninsular Thailand and Malaysia this species inhabits almost every protected forest area. It is also protected by the WARPA 1992 law of Thailand.
IUCN SSC Amphibian Specialist Group 2014. Phrynoidis asper. In: IUCN 2014