|Scientific Name:||Xenopus gilli Rose & Hewitt, 1927|
|Taxonomic Source(s):||Frost, D.R. 2016. Amphibian Species of the World: an Online Reference. Version 6.0 (31 March 2016). New York, USA. Available at: http://research.amnh.org/herpetology/amphibia/index.html.|
|Taxonomic Notes:||A deep genetic split characterises the disjunct distribution of this species.|
|Red List Category & Criteria:||Endangered B1ab(ii,iii,v)+2ab(ii,iii,v) ver 3.1|
|Assessor(s):||IUCN SSC Amphibian Specialist Group, South African Frog Re-assessment Group (SA-FRoG)|
|Contributor(s):||Channing, A., Rebelo, A., Turner, A.A., de Villiers, A., Becker, F., Harvey, J., Tarrant, J., Measey, G.J., Tolley, K., Minter, L., du Preez, L., Burger, M., Cunningham, M.J., Baptista, N., Davies, S., Hopkins, R., Conradie, W. & Chapeta, Y.|
|Facilitator/Compiler(s):||Rebelo, A., Garollo, E., Measey, G.J., Neam, K.|
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.
|Previously published Red List assessments:|
|Range Description:||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.|
Native:South Africa (Western Cape)
|Range Map:||Click here to open the map viewer and explore range.|
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).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||It is found only in Cape fynbos heathland, is a winter breeder (July to October), and aestivates if waterbodies dry up. It does not tolerate alteration of its habitat, and the larvae are very sensitive to changes in water quality.|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Movement patterns:||Not a Migrant|
|Use and Trade:||In this past this species was traded along with Xenopus laevis, but there are currently no records of this species being utilized.|
|Major Threat(s):||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.|
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).
Habitat management and restoration, including removal of X. laevis and alien plants, are 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.
Baard, E.H.W. 1989. The status of some rare and endangered endemic reptiles and amphibians of the southwestern Cape Province, South Africa. Biological Conservation 49: 161-168.
Channing, A. 2001. Amphibians of Central and Southern Africa. Cornell University Press, Ithaca and London.
de Villiers, A.F., de Kock, M. and Measey, J.G. 2016. Controlling the African clawed frog Xenopus laevis to conserve the Cape platanna Xenopus gilli in South Africa. Conservation Evidence 13: 17.
du Preez, L. and Carruthers, V. 2009. A Complete Guide to the Frogs of Southern Africa. Struik Nature, Cape Town.
Evans, B.J., Morales, J.C., Picker, M.D., Kelley, D.B. and Melnick, D.J. 1997. Comparative molecular phylogeography of two Xenopus species, X. gilli and X. laevis, in the south-western Cape Province, South Africa. Molecular Ecology 6: 333-343.
Evans, B.J., Morales, J.C., Picker, M.D., Melnick, D.J. and Kelley, D.B. 1998. Absence of extensive introgression between Xenopis gilli and Xenopus laevis laevis in the southwestern Cape Province, South Africa. Copeia 1998: 504-509.
Fogell, D.J., Tolley, K.A. and Measey, J.G. 2013. Mind the gaps: investigating the cause of the current range disjunction in the Cape Platanna, Xenopus gilli (Anura: Pipidae). PeerJ 1:e166: 1-23.
IUCN. 2017. The IUCN Red List of Threatened Species. Version 2017-2. Available at: www.iucnredlist.org. (Accessed: 14 September 2017).
Minter, L.R., Burger, M., Harrison, J.A., Braack, H.H., Bishop, P.J. and Knoepfer, D. 2004. Atlas and Red Data Book of the Frogs of South Africa, Lesotho and Swaziland. SI/MAB Series No. 9, Washington, D.C.
Picker, M.D. and de Villiers, A.L. 1989. The distribution and conservation status of Xenopus gilli (Anura: Pipidae). Biological Conservation 49: 169-183.
Picker, M.D., Harrison, J.A. and Wallace, D. 1996. Natural hybridisation between Xenopus laevis laevis and X. gilli in the south-western Cape Province, South Africa. In: Tinsley, R.C. and Kobel, H.R. (eds), The Biology of Xenopus, pp. 61-71. Zoological Society of London, Oxford.
Picker, M.D., McKenzie, C.J. and Fielding, P. 1993. Embryonic tolerance of Xenopus (Anura) to acidic blackwater. Copeia 1993: 1072-1081.
Rau, R.E. 1978. The development of Xenopus gilli Rose & Hewitt (Anura, Pipidae). Annals of the South African Museum 76(6): 247-263.
Simmonds, M.P. 1985. Interactions between Xenopus species in the south-western Cape Province, South Africa. South African Journal of Science 81: 200.
Tinsley, R.C. and Kobel, H.R. 1996. The Biology of Xenopus. Zoological Society of London, Clarendon Press, London.
Vigny, C. 1979. The mating calls of 12 species and sub-species on the genus Xenopus (Amphibia: Anura). Journal of Zoology 168: 103-122.
|Citation:||IUCN SSC Amphibian Specialist Group, South African Frog Re-assessment Group (SA-FRoG). 2017. Xenopus gilli. The IUCN Red List of Threatened Species 2017: e.T23124A77164368.Downloaded on 24 February 2018.|
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