This species is confined to a very small area of the Klein Swartberg near Caledon, Western Cape Province, South Africa, between 500-800 m asl. It occurs in one threat-defined location, its area of occupancy (AOO) is 14 km2, and the extent of occurrence (EOO) is 22 km2.
Habitat and Ecology
This species occupies indigenous fynbos heathland vegetation and can be found in dense restios stands in close proximity to seepages. It is a direct developing species laying around 10 eggs like other members of the genus.
Extensive survey work has been conducted and the number of mature individuals was estimated to be around 1,000 at the time of the last assessment in 2009. The three easternmost localities of this species within one subpopulation are regularly monitored by CapeNature, and population estimates are made using a standardised monitoring protocol (Measey et al. 2011, A. Turner pers. comm. August 2016). Fire and post-fire impacts on number of mature individuals cause large fluctuations in subpopulation sizes. Due to ongoing decline in the extent and quality of habitat, the population is suspected to be decreasing.
The main threats to this species are fires, which cause extreme population fluctuations and have a synergistic effect on alien invasive plants which are degrading and drying seepages. Both threats are extensive and severe on the entire distribution of this species.
This species has not been recorded in any protected areas. A monitoring programme has been put in place by CapeNature and three sites within a subpopulation are regularly monitored.
An invasive alien plant clearing plan is a priority and is being developed by CapeNature and private land owners (with all known sites of this species included - J. Measey and A. Turner pers. comm. August 2016). The plan for Klein Swartberg Mountain is still requiring to be drawn up and implemented.
A key area of research for the conservation of this species is the identification of the impact of threats and their subsequent management. This and other members of the genus also require more information on life history, dispersal and population size, and would benefit from population monitoring.
Red List Status
Critically Endangered (CR)
Listed as Critically Endangered because its extent of occurrence (EOO) is 22 km2, it occurs in one threat-defined location, there is continuing decline in the extent and quality of habitat, and the ongoing threats of fire and invasive vegetation are causing large population fluctuations to a very small population of adult individuals.
IUCN SSC Amphibian Specialist Group & South African Frog Re-assessment Group (SA-FRoG) 2016. Arthroleptella rugosa. The IUCN Red List of Threatened Species 2016: e.T174664A77162276. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T174664A77162276.en .Downloaded on 23 January 2019