This species is currently known only from Mount Balabag, in the Mantalingajan mountain range, on the island of Palawan in the western Philippines, between 500–900 m asl. It might range more widely. It is known from one threat-defined location and its extent of occurrence (EOO) is 788 km2.
Habitat and Ecology
This semi-aquatic species occurs in sub-montane and montane forest along streams and rivers along which it has been observed perching on rocks and boulders. It probably breeds on land by direct development, like other members of its genus (Philippines Red List Assessment Workshop May 2017).
Surveys in 2001 and 2007 found the species to be common to abundant at elevations between 500–900 m asl (R. Brown pers. comm. 2007, Philippines Red List Assessment Workshop May 2017). Due to ongoing decline in the extent and quality of habitat, the population is suspected to be decreasing.
The major threat is the destruction and conversion of both lowland and montane rainforest habitat on Palawan due to small-scale agricultural activities, large-scale oil palm plantations, wood collection for charcoal production, and expanding human settlements due to high levels of immigration (Philippines Red List Assessment Workshop May 2017). There are applications for mining the nickel, chromite, and gold in the region, but no mining activities are currently permitted within the range (Philippines Red List Assessment Workshop May 2017).
The species does not occur in an official protected area, but the Mantalingajan mountain range is generally well protected.
The Strategic Environmental Plan (SEP) for Palawan Act was enacted by the national government in 1992, which aims to divide the island into a network of environmentally critical areas above 1,000 m asl (ECAN - Environmentally Critical Areas Network). The plan is operationalized on a local level by the Palawan Council for Sustainable Development. The map of these areas is currently being updated to also include lowland areas below 1,000 m asl.
In 2016, an endowment fund for the conservation of Mt. Mantalingahan Protected Landscape (MMPL) was launched with a US $1 million grant from its Conservation International Philippines' Global Conservation Fund. The funds are held by the Philippine Tropical Forest Conservation Foundation and will provide sustainable financing for the long-term maintenance, protection and enrichment of the biodiversity within the protected area.
Philippine Tropical Forest Conservation Foundation is also managing about $30 million in funds from debt payments due to the US government, which are instead allocated for spending during 2016-2026 towards forest protection in three priority areas: Palawan Island, the Sierra Madre on Luzon Island, and eastern Mindanao Island.
The effective protection of the remaining lower montane and lowland rainforest on Palawan is the most significant conservation measure required.
Field surveys are needed to gather updated information on the population size, distribution and trends of this species.
Red List Status
Data Deficient (DD)
Listed as Endangered because its extent of occurrence (EOO) is 788 km2, it occurs in fewer than five threat-defined locations, and there is a continuing decline in the extent and quality of its habitat in Palawan.
IUCN SSC Amphibian Specialist Group 2018. Alcalus mariae. The IUCN Red List of Threatened Species 2018: e.T41226A114911328. http://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T41226A114911328.en .Downloaded on 20 November 2018