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 Sarah Davies Rob Hopkins Peter Conradie Yankho Chapeta
Facilitators: Alex Rebelo Elena Garollo John Measey Kelsey Neam
Reviewers: Jennifer Luedtke

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

Listed as Endangered due to its declining area of occupancy (AOO) currently being 60 km2, severely fragmented population, and continuing decline in the quality of its habitat and number of mature individuals.

Distribution

This species is endemic to extreme southwestern South Africa, occurring on the Cape Peninsula, and nearby Cape flats and the southwestern Cape coast in only four disjunct areas (Fogell et al. 2013, de Villiers et al. 2016). It is a low-altitude species occurring at 10–140 m Asl; currently known populations occur within 10 km of the coast. Recent discoveries of relict populations of this species at two sites on the Cape flats, to the northeast of the Cape Peninsula (J. Measey pers. comm. November 2015) have resulted in an increase in the AOO and number of threat-defined locations. Its extent of occurrence (EOO) is 4,602 km2 and the new AOO is 60 km2. The AOO is considered to be declining and its range is comprised of nine threat-defined locations.

Population trend

Trend

It appears to be relatively abundant at some of the known localities, but the population is considered to be severely fragmented because the distances of c. 100 km between subpopulations is considered to be too great for dispersal within one generation. Moreover, subpopulations on opposite sides of False Bay have undergone appreciable genetic and phenotypic divergence (Evans et al. 1997, Fogell et al. 2013, Conlon et al. 2015). Predation, hybridization and competition from Xenopus laevis, which occurs in sympatry with this species, have caused a decline in the number of mature individuals in the past, which is still ongoing in some subpopulations (Fogell et al. 2013, de Villiers et al. 2016). In the Cape of Good Hope Section of Table Mountain National Park (CoGH), active conservation with annual removal of X. laevis was in place during 1985–2000 (de Villiers et al. 2016). In 2010, a new monitoring programme was initiated at CoGH, which included the removal of X. laevis and a marked increase in juvenile and young adults of X. gilli within five years (de Villiers et al. 2016). However, at the Kleinmond site, situated on privately owned land with no active conservation in place, recruitment appears suppressed, with a lower overall number of individuals of this species compared with the CoGH site (de Villiers et al. 2016).

Threats

The main threat to this species is represented by competition, predation and hybridization from Xenopus laevis. On the Cape Peninsula the level of hybridization is quite low (2.5%), but it is high in ponds near Kleinmond (27%); in ponds near Pearly Beach, previously thought to contain only X. gilli, hybrids comprised 8% (Fogell et al. 2013). Recruitment at the Kleinmond site appears suppressed with low overall number of individuals, probably as X. laevis is not controlled there (de Villiers et al. 2016). The eastern subpopulation, which occurs over a wider area compared with the western population, is also threatened by invasive alien plants (Fogell et al. 2013). Additional known threats include habitat loss due to urbanization and agricultural run-off.

Uses and trade

In this past this species was traded along with Xenopus laevis, but there are currently no records of this species being utilized.

Conservation

Conservation Actions
It occurs in Cape Peninsula National Park and Agulhas National Park, both of which are relatively well managed, although there is a need to control the spread of invasive plants within these areas. Regular removal of Xenopus laevis at the Cape of Good Hope Section of the Table Mountain National Park (CoGH) is part of the Annual Plan of Operations for the South African National Parks (SANParks), and negotiation for a formal arrangement for Kleinmond site is ongoing (de Villiers et al. 2016).

Conservation Needed
Habitat management and restoration, including removal of X. laevis and alien plants, are needed.

Research Needed
Studies on its life history and ecology, population size, distribution and trends, including estimating dispersal capabilities, identification of management units and monitoring population size are needed. Further research should focus on threats to this species.

References 

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,]
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