This species occurs on the high plateau of Mount Mulanje, above 1,700 m Asl, in southern Malawi, one of a group of a granite inselbergs extending into neighboring Mozambique; the species is "unmistakable" and should be looked for in similar habitat that extends into this neighboring country (Channing et al. 2016). It has an EOO of 663 km2 and, due to its strong association with its aquatic habitat, it is considered to occur in five threat-defined locations which correspond to the rivers on Mulanje.
Habitat and Ecology
It is a strongly aquatic species associated with pools in cold mountain streams in montane grassland and forest, but it does not survive in secondary habitats. It breeds in streams and the larvae apparently remain in the water for two years before metamorphosing. It has been observed catching and eating crabs underwater and survives below ice in winter (Channing et al. 2016).
It is common and widespread in its restricted range—this was confirmed from surveys in 2009 (Conradie et al. 2011) with many tadpole, but few adult observations (W. Conradie pers. comm. June 2016)—while the widespread Amietia delalandii is found along the base and lower slopes of Mount Mulanje (Channing et al. 2016). Due to ongoing decline in the quality of its habitat, and potential predation by non-native fish, the population is suspected to be decreasing.
Mount Mulanje is a UNESCO-MAB Biosphere reserve and although it is somewhat protected, both the forest and grassland habitats continue to be lost in places as a result of expanding human settlement, small-scale subsistence agriculture, planting of pine plantations (and their subsequent logging) and illegal logging of native forest by local people. These activities are likely to result in the siltation of streams and affect the microclimate by removal of the forest canopy. Non-native trout have been stocked on Mount Mulanje and are known to use the lake's tributaries, threatening stream-dwelling larvae of the species (J. Harvey pers. comm. June 2012). As with other high-altitude species, it may be vulnerable to climate change, especially as it is dependent on perennial streams fed by rainfall. Finally, chytridiomycosis has been confirmed for the species, with one in four specimens infected, but no die-offs were found (Conradie et al. 2011).
It occurs in the Mount Mulanje Forest Reserve, which is a UNESCO Biosphere Reserve.
Improved protection of the species' habitat and strengthened management of this area is essential.
Monitoring the effects of chytridiomycosis is also recommended as it is known to cause rapid declines in other amphibian species. More information is needed on its distribution, population status, natural history, and threats.
Red List Status
Listed as Endangered because its extent of occurrence (EOO) is 663 km2, all individuals are known from five treat-defined locations, and there is continuing decline in the extent and quality of its habitat on Mount Mulanje.
IUCN SSC Amphibian Specialist Group 2017. Amietia johnstoni. The IUCN Red List of Threatened Species 2017: e.T58188A17162971. http://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T58188A17162971.en .Downloaded on 18 November 2018