Red List of South African Species

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Endangered (EN)
Assessors: IUCN SSC Amphibian Specialist Group South African Frog Re-assessment Group (SA-FRoG)
Contributors: Alan Channing Alex Rebelo Andrew A Turner Atherton L de Villiers Francois Becker James Harvey Jeanne Tarrant John Measey Krystal A Tolley Leslie Minter Louis du Preez Marius Burger Michael Cunningham Ninda Baptista Rob Hopkins Sarah Davies Peter Conradie Yankho Chapeta
Facilitators: Alex Rebelo Elena Garollo John Measey Kelsey Neam
Reviewers: Ariadne Angulo

Rationale (Changed due to Same category and criteria)

Listed as Endangered because its area of occupancy (AOO) is 188 km2, its distribution is considered severely fragmented, and there is a continuing decline in both extent and quality of its habitat and area of occupancy.

Distribution

This species is restricted to southeastern South Africa, where it ranges from Manubi State Forest Reserve (Venter and Conradie 2015) in the Eastern Cape Province, to southern and central KwaZulu-Natal Province. It is restricted to lowland riparian forest patches within this range. Its elevational range is between 50 and 900 m asl. Its extent of occurrence (EOO) is 11,631 km2 and its area of occupancy (AOO) is 188 km2.

Decline

This species is considered to be severely fragmented as >50% of individuals occur in isolated patches and the distances between subpopulations are considered to be too great for dispersal within one generation.

Population trend

Trend

Little population information is available for this species. It is considered to be severely fragmented as 50% of individuals are in isolated patches and the distances between subpopulations are considered to be too great for dispersal within one generation. A population genetic study has commenced to address these questions, and a monitoring protocol has been developed and tested to help provide information on local abundance and breeding success. Where habitat and conditions are suitable, the species is locally abundant, but does appear sensitive to stressors such as drought and siltation, which affect breeding output (J. Tarrant pers. comm. August 2016). The species is considered to be extinct at sites around Pietermaritzburg, including Chase Valley and Oribi, as searches at the sites have been unable to detect it. Its presence at Kranskop was first and last recorded in 1958 by Poynton; however, there has been little search effort at this site and its presence there remains uncertain.

Threats

Much of the forest habitat of this species has been historically lost to sugarcane cultivation and other agriculture, woodcutting, afforestation and urbanization, all of which are ongoing threats to the subpopulations of KwaZulu-Natal Province. Mining of the Marble Delta in in the Oribi/Port Shepstone area is also likely to have caused, and continues to cause, direct habitat loss. It is also threatened by pollution and siltation of streams. An emerging threat includes alien invasive vegetation.

Uses and trade

There are no records of this species being utilized.

Conservation

Conservation Actions
It occurs in several protected areas, including Vernon Crookes, Oribi Gorge, Krantzloof, Umtamvuna, and Umbumbazi Nature Reserves in KwaZulu-Natal and Dwesa-Cwebe Nature Reserve in the Eastern Cape (du Preez 2004). It has more recently been confirmed at Silaka Nature Reserve, Hluleka Nature Reserve and Manubi State Forest in the Eastern Cape (Venter and Conradie 2015), and at Crowned Eagle Conservancy, Springside Nature Reserve and Tanglewood Nature Reserve in KwaZulu-Natal (J. Tarrant pers. comm. August 2016). A monitoring protocol has been developed and implemented at several sites through volunteers, pupils and reserve rangers (Vernon Crookes, Crowned Eagle Conservancy, Silaka, Hluleka, and Dwessa-Cwebe Nature Reserves). 

Conservation Needed
Improvement of the management in place in the protected areas where the species occurs would be important, together with additional habitat and headwater protection. 

Research Needed
A priority for conservation research is to estimate the population size of adults in subpopulations, as well as determining the cause of direct threats. Further studies on its population size, distribution and trends, as well as on it's life history and ecology are needed. Additional surveys are need at sites where the species presence is uncertain. A genetic study is currently underway to examine the subpopulation structure and connectivity between the populations (J. Tarrant pers. comm. August 2016). This study also aims to provide information on effective population size, through the analysis of long-term monitoring data, and genetic diversity present within populations.

References 

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,]
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