AMPHIBIAWEB
Anhydrophryne ngongoniensis
Mistbelt moss frog, Ngongoni moss frog, Mistbelt chirping frog
family: Pyxicephalidae
subfamily: Cacosterninae
Conservation Status (definitions)
IUCN (Red List) Status Critically Endangered (CR)
CITES No CITES Listing
Other International Status None
National Status Critically Endangered
Regional Status None

 

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Description
The dorsal colouration is fairly uniform in all individuals (no sexual dimorphism), being a base of sandy to golden brown with four indistinct stripes, composed of small dark brown spots. There is a broad dark brown stripe (bordered ventrally and dorsally by a thin white/silvery stripe) beginning at the tip of the snout, passing through the nostril, eye and tympanum and ending at the axilla. The belly is white, while the ventral surface of the limbs and throat are pale yellow.

This species can be easily identified by its call and it is often difficult to locate the calling frog without destroying its habitat. Males produce a very soft, trilled, cricket-like call, repeated three or four times with an interval of about one second between calls. The call consists of 8-10 pulses with a duration of 55 ms and the frequency at the midpoint is 4.5 kHz (Bishop and Passmore 1993). Males call in bouts of up to seven calls often alternating with an adjacent male.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: South Africa

 

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The Mist Belt Moss Frog is endemic to a small region of KwaZulu-Natal, South Africa, where it is confined to indigenous grassy slopes, above 1000m elevation, in the mist belt of the eastern escarpment. It has a very restricted range in the Ixopo and Weza districts with an area of occupancy of less than 10km2. The frogs are not very abundant and were only known from three isolated localities within 11 km of the type locality, prior to the work for the Southern African Frog Atlas Project (Minter et al. 2004).

The breeding and non-breeding habitat is Short Mistbelt Grassland and Moist Upland Grassland (Minter et al. 2004). Preferred sites are above 1000 m elevation and consist of fairly steep slopes (30-40°) on either side of seepage channels, covered with a dense growth of indigenous grasses. These areas are well protected from fire, being bordered on all sides by exotic tree plantations. The frogs spend most of their time at the base of grass and sedge tussocks amongst the network of loose tunnels in the decaying vegetation.

Life History, Abundance, Activity, and Special Behaviors
Males call throughout the day and night on misty days, but only during the night when the humidity is lower. During the day males call from very concealed positions at the base of grass tussocks, while at night they climb to calling positions about 20 cm below the tips of the grass stems and can be easily seen. Males do not posses a vocal sac and produce a fairly quiet call. The small size of the adult frog (16 - 22 mm) coupled with the softness of their call are probably the main reasons why the frog remained undetected for so many years. Eleven to 14 unpigmented eggs are laid on damp soil or vegetation at the base of grass tussocks and the tadpoles undergo complete development within the egg capsule, emerging as fully formed froglets approximately 27 days after egg laying (Bishop and Passmore, 1993).

Although there are no documented accounts of predators, these are likely to include snakes, other frog species and invertebrates, while prey includes ants, termites, insect larvae, and other small invertebrates characteristic of the grassland leaf litter.

Trends and Threats
The major threat to this species is habitat loss and fragmentation due to afforestation and other agricultural practices. The ongoing encroachment of alien trees and plantations are likely to alter moisture regimes and the presence of quantities of woody vegetation can cause potentially lethal hot burns during wild fires. Future harvesting of timber also has the potential to cause serious damage to their habitat over a short period of time.

In addition, all the grasslands types in which this species occur are poorly conserved and in the absence of fire, afromontane forest and grassy fynbos may invade these grasslands.

Relation to Humans
One population occurs on land under the management of Singisi Forest Products. The conservation importance of this site was brought to the attention of this company and they responded positively by appointing a consultant to draw up a management plan and monitoring protocol. Efforts were underway as of January 2003 to obtain permanent protection for the site, the first initiative in South Africa to establish a nature reserve specifically for the protection of frogs (Minter et al. 2004).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Subtle changes to necessary specialized habitat
Habitat fragmentation

Comments
Urgent conservation action was recommended by Harrison et al. (2001) as it was thought that the situation with regard to this species could deteriorate very rapidly. A population and habitat viability assessment was recommended, along with a detailed survey to identify the location and size of the remaining populations of this species. In particular, it was considered important that the only remaining protected areas of moist upland grasslands were extensively surveyed to detect any previously unknown populations.

Management recommendations include the establishment of a monitoring programme, wild population management, habitat management and limiting factor management. In view of its extremely restricted and fragmented distribution, priority should be given to the conservation and management of the remaining habitat before this species becomes extinct.

This species was transferred to the monotypic genus Anhydrophryne by Dawood and Stam (2006).

References

Bishop, P.J., and Passmore, N.I. (1993). ''A new species of Arthroleptella Hewitt (Ranidae:Phrynobatrachinae) from the mist belt of the Natal highlands, South Africa.'' Annals of the Transvall Museum, 36(3), 17-20.

Dawood, A. and Stam, E. M. (2006). ''The taxonomic status of the monotypic frog genus Anhydrophryne Hewitt from South Africa: a molecular perspective.'' South African Journal of Science, 102, 249-253.

Harrison, J. A., Burger, M., Minter, L. R., De Villiers, A. L., Baard, E. H. W., Scott, E., Bishop, P. J., and Ellis, S. (2001). Conservation Assessment and Management Plan for Southern African Frogs. Final Report. IUCN/SSC Conservation Breeding Specialist Group, Apple Valley, MN.

Minter, L.R., Burger, M., Harrison, J.A., Braack, H.H., Bishop, P.J., and Kloepfer, D. (eds.) (2004). Atlas and Red Data Book of the Frogs of South Africa, Lesotho and Swaziland. Volume 9 SI/MAB Series. Smithsonian, Washington D.C..



Written by Phil Bishop (phil.bishop AT stonebow.otago.ac.nz), University of Otago
First submitted 2004-10-05
Edited by Kellie Whittaker (2010-08-16)

Species Account Citation: AmphibiaWeb 2010 Anhydrophryne ngongoniensis: Mistbelt moss frog <http://amphibiaweb.org/species/3716> University of California, Berkeley, CA, USA. Accessed Oct 20, 2017.



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Citation: AmphibiaWeb. 2017. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 20 Oct 2017.

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