|Scientific Name:||Capensibufo rosei (Hewitt, 1926)|
Bufo rosei Hewitt, 1926
|Taxonomic Source(s):||Channing, A., Measey, G.J., De Villiers, A.L., Turner, A.A. and Tolley, K.A. 2017. Taxonomy of the Capensibufo rosei group (Anura: Bufonidae) from South Africa. Zootaxa 4232(2): 282–292.|
|Taxonomic Notes:||Phylogenetic analysis of this genus showed the presence of multiple lineages in what had originally been attributed to two species (Capensibufo rosei and C. tradouwi). Within C. rosei, at least five distinct lineages are present, such that Capensibufo rosei on the Cape Peninsula is now recognized as the only member of this taxon, with others being Capensibufo deceptus, C. magistratus and C. selenophos (Tolley et al. 2010, Cressey et al. 2014, Channing et al. 2017).|
|Red List Category & Criteria:||Critically Endangered B1ab(iii,iv)c(ii)+2ab(iii,iv)c(ii) 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., Cunningham, M.J., Baptista, N., Hopkins, R., Conradie, W. & Chapeta, Y.|
|Facilitator/Compiler(s):||Garollo, E., Luedtke, J.|
Listed as Critically Endangered in view of the very restricted area of occupancy (AOO) of 1.5 km2, its small extent of occurrence (EOO) of 25 km2, with all individuals known from only two threat-defined locations that are considered severely fragmented, and a continuing decline in the extent and quality of its habitat.
The distribution of this species was previously thought to extend from the Cape Peninsula to the mountains west of the Breede River Valley in southwestern South Africa. It is now limited to the Cape Peninsula, currently known only from both the Silvermine (known by different names: Kalk Bay Mountain, Muizenberg Mountain, Steenberg Plateau, and Silver Mine Nature Reserve) and Cape of Good Hope sections of the Table Mountain National Park between 60 to 1,000 m asl (Channing et al. 2017). Historically, it was recorded from five breeding sites (as well as a number of single individuals elsewhere) on the Cape Peninsula, with a sixth site discovered in 2010; however, a reduction in the number of sites has been recorded over the last 20 years and recent dedicated surveys have only recovered animals from two breeding sites which are 22 km apart (Cressey et al. 2014). No specimens have been found on Table Mountain itself since 1983 (Cressey et al. 2014).
Native:South Africa (Western Cape)
|Range Map:||Click here to open the map viewer and explore range.|
Within the Cape Peninsula only two breeding subpopulations are known, with several other breeding subpopulations having disappeared since the 1980s (Cressey et al. 2014). The declines are enigmatic, as several subpopulations occurred within protected areas and there is no direct link to disease or anthropogenic causes such as habitat loss or fragmentation (Cressey et al. 2014). Tarrant et al. (2013) found no chytrid fungus in the Silvermine subpopulation. The species' population is considered to be severely fragmented as the only two breeding sites are separated by 22 km and a genetic study showed that no mitochondrial haplotypes were shared between them (Cressey et al. 2015).
|Current Population Trend:||Unknown|
|Habitat and Ecology:|
This species occurs in montane fynbos heathland, breeding in areas with low, open vegetation. Adults congregate to breed in temporary pools from late July to early September, where they lay around 100 eggs in strings of jelly. Breeding takes place in temperate (12–22 C°), shallow pools (1–2 cm depth) with muddy bottoms and no overhanging or encroaching vegetation (Edwards et al. 2017). Pools contain from tens to hundreds of tadpoles that usually metamorphose and disperse by late September to late October (Edwards et al. 2017). The encroachment of vegetation, due to exclusion of fire through fire prevention management and the exclusion of grazers from the ecosystem, is potentially a factor in local extinctions of historical breeding sites. Ground-truthing shows that in the sites predicted to be suitable, the fynbos vegetation has formed a dense cover and no open pools are available (Becker 2017).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Movement patterns:||Not a Migrant|
|Congregatory:||Congregatory (and dispersive)|
|Use and Trade:||
There are no records of this species being utilized.
The main threat identified to this species is the loss, fragmentation and disturbance of its fynbos habitat, due to human disruption of natural processes and direct habitat transformation (Cressey et al. 2014). Direct transformation is no longer a threat, and the remaining populations are within a protected area. However, these toadlets tend to breed in small open patches, and the exclusion of fire for management purposes at some localities in this naturally fire-prone habitat (fynbos) has allowed vegetation to become dense, possibly contributing to local extinctions of formerly known breeding subpopulations. In addition, where present (i.e. Cape of Good Hope) the large mammal fauna cause vegetation disturbance which allow small open patches to persist, and toads tend to breed in these disturbed areas. For these reasons, the loss of the large mammal fauna over the remainder of the Cape Peninsula may be detrimental to the breeding success of this toad. Despite these potential causes, no concrete explanation or threat has been deduced for historical subpopulations now presumed extinct (no individuals recorded from these populations in recent surveys), and so part of this decline still appears enigmatic (Cressey et al. 2014). As all the known individuals are in two subpopulations (corresponding to two locations) with no dispersal between them, they are particularly vulnerable to any stochastic population fluctuation (which is common in toads). For example, the subpopulation at Cape of Good Hope was thought to have low or no recruitment in 2011 due to presumed predation of eggs (Cressey et al. 2014), although that subpopulation has since recovered (Becker 2014), possibly as a result of mitigation measures (see Conservation section). One subpopulation occurs in a public access area and may be negatively impacted by walkers who ignore signs not to enter the area during breeding. It should also be noted that the breeding sites occasionally experience a low rainfall year, and this could impact recruitment, if tadpoles are unable to metamorphose in time to disperse. While such fluctuations are likely natural for this species, the perturbation of the entire system, and the loss of entire breeding sites, make this a potential threat, as there is little to no redundancy in the system.
|Citation:||IUCN SSC Amphibian Specialist Group, South African Frog Re-assessment Group (SA-FRoG). 2017. Capensibufo rosei. The IUCN Red List of Threatened Species 2017: e.T112716154A47759127.Downloaded on 12 December 2017.|
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