This species is endemic to Java, Indonesia. It was previously known from west Java in Mount Gede Pangrango National Park, Mount Haliman-Salah National Park and Curug Cilember, and from Petungkriyono district, Pekalongan Regency and Mount Ungaran National Park, Kendal Regency in central Java, between 360–1,600 m asl. It is now also known from Kedung Kayang River, Magelang regency in central Java at 360 m asl (Qurniawan et al. 2010), in the valley of Mount Kelud near Ironggolo waterfall in Kediri Regency in East Java (Habiburrahman Faz 2017), Tawangrejo village in Jatirejo District, Mojokerto Regency at 600 m asl, Sendi campground, Watu Lampung village in Pacet District, Mojokerto Regency at 1,300 m asl, and Taman Hutan Raya Raden Soerjo, all in East Java (H.P. Wicesa unpubl. data April 2018), and from Cangar in the valley of Mount Arjuna in East Java (Mumpuni and Riyanto 2013). It may occur more widely in the eastern highlands of East Java, however further surveys are required (Indonesia Red List Assessment Workshop May 2017).
Habitat and Ecology
This species is restricted to unpolluted, clear, fast-flowing streams and torrents, in forests and in somewhat more open areas, including areas near human habitations and agricultural areas (H. Kurniati pers. obs. May 2017). It inhabits torrent streams where dense low vegetation occurs along streams bank, so it is not easy to find the frogs in their suitable habitats, but it can be detected by listening its call (Kurniati 2012). Breeding takes place in streams.
It is a common species in the majority of its range, and it is considered to be abundant from a high call frequency in Boonan and Kurniati (2012). However, it was considered to be uncommon in Gunung Merapi foot hill in Central Java after volcano eruption (Cahyandra et al. 2012). Surveys in 2009 recorded this species in Petungkriyono District, Pekalongan Regency (Eprilurahman et al. 2010). Due to ongoing decline in the extent and quality of habitat, the population is suspected to be decreasing.
Soil erosion and the sedimentation of streams are the main threats to this species. These threats, which result from habitat modification taking place around streams mostly caused by rice agriculture, are leading to a rapid loss of suitable habitats within its range. Mining of the sand within the streams (for house building materials) is also a threat as it affects the flow of water, which disturbs the tadpoles of this species (M. Kusrini and R. Eprilurahman pers. comm. May 2017).
This species is found in Halimun National Park, Ujong Kulon National Park, Gunung Gede Pangrango National Park, and Dieng Nature Reserve.
Habitat protection is required, particularly of its' stream habitats.
Red List Status
Listed as Least Concern in view of its relatively wide distribution, tolerance of a degree of habitat modification and presumed large population.
IUCN SSC Amphibian Specialist Group 2018. Huia masonii. The IUCN Red List of Threatened Species 2018: e.T58303A114920315. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T58303A114920315.en .Downloaded on 21 January 2019