SANBI

Rationale (Changed due to Same category but change in criteria)

Listed as Critically Endangered because its extent of occurrence (EOO) is 8 km² and its area of occupancy (AOO) is c. 4 km², it occurs in a single threat-defined location, and there is a continuing decline in the extent and quality of its habitat.

Distribution

This species occurs in a single threat-defined location and has a very restricted range as it is endemic to the southern and eastern slopes of Table Mountain, in the Western Cape province, extreme southwestern South Africa, between 240–1,060 m Asl. It was historically recorded from eight streams, but is currently only present in five. It is no longer present in Platteklip Gorge, Valley of the Red Gods and Cecilia streams (A. de Villiers pers. comm. August 2016). The Cecilia subpopulation is considered to have been locally extinct for decades (Minter et al. 2004). Its AOO is around 4 km²and its EOO is 8 km².

Decline

see threats

Habitat View more ecological information

Population trend

Trend

Adults of this species are elusive, and are only seen occasionally, whereas tadpoles are typically plentiful where habitat is suitable. Subpopulations on Disa and Original Disa streams are considered stable (Minter et al. 2004; de Villiers unpub. data 2015) as the habitat there is not impacted. The number of tadpoles in Skeleton Gorge may have decreased, but monitoring of tadpole numbers suggests that populations at Windows and Skeleton Gorges are likely stable at present above the water abstraction point (K. A. Tolley, E. Le Roux and A. de Villiers unpub. data 2014). However, during the summer, the stream below abstraction point dries up and is likely to cause declines within the subpopulations at Windows Gorge as tadpoles cannot survive. In recent years, tadpoles were rarely recorded from Nursery Gorge (A. de Villiers, unpub. data 2015). Tadpoles were historically found in Cecelia Gorge, but they have not been recorded since 1980 (Minter et al. 2004) due to heavy land transformation and afforestation around that stream. It is thought that they are locally extinct at that locality (Minter et al. 2004), although it should be noted that the upper reaches of Cecelia were not transformed but have not been searched due to difficulty of access.

At least two of the streams (Windows and Skeleton Gorges) can be considered a single genetic population (K. A. Tolley unpub. data), while other streams have not yet been investigated.

Threats

The main threats are the spread of alien vegetation, suppression of the natural fire regime in fynbos potentially causing bush encroachment, and the presence of water storage reservoirs on the mountain which can affect the consistency of stream-flow. Soil erosion caused by human pedestrian traffic on hiking paths may be a threat around some of the streams (Skelton Gorge and Nursery Ravine). Water abstraction from Windows Gorge by Kirstenbosch Gardens has resulted in 150 m of habitat loss below the abstraction point and limits the vertical movement of tadpoles in summer when abstraction occurs (K. A. Tolley unpub. data 2015). Monitoring in 2013 showed that c. 27% of the total tadpole counts in Windows Gorge and 24% of metamorphs were below this abstraction point during spring, with these pools becoming dry and vacant of individuals once abstraction began in January 2014 (K. A. Tolley unpub. data 2013). It is presumed that any tadpoles below the abstraction point are eliminated from the population once abstraction begins.

Plantations (for exotic trees) used to be a threat but have now been largely removed so that these no longer pose a risk to the species. Other threats to this species which are listed have not been quantified and assessments of each must be made in order to unify the future conservation effort.

Uses and trade

There are no records of this species being utilized.

Conservation

Conservation Actions
This species' entire range is incorporated in the Table Mountain National Park, which is believed to protect more than 70% of the species' population, and the estate of Kirstenbosch National Botanic Gardens (South African National Biodiversity Institute) which has no special protection. The species has been considered Endangered since 1998 (and Critically Endangered since 2004). In 2014, the Table Mountain Ghost Frog Action Group was formed consisting of the main stakeholders, to review the threats and to establish an action based framework for conservation of this species.

Research and monitoring are being carried out to estimate population size through occupancy modeling, and to establish whether there is connectivity between streams using genetic analyses. Each stream is also being systematically surveyed over their entire lengths to record presence/absences.The monitoring of tadpole populations and threats to stream habitat will continue.

Conservation Needed
High priorities for action relate to rehabilitation of Cecelia Gorge by SANParks, improvement of water quality in Skeleton Gorge, and setting ecological reserves (including improvement of stream habitats below water abstraction points) for Nursery and Windows Gorges.

Research Needed
The relative impact of threats must be researched, and an action plan would allow highlights for areas requiring future work (A. de Villiers pers. comm. August 2016).

References

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,]

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