In August 2010, as part of the ASG’s global Lost Frog Campaign, a team of six South African froggers headed for the Amathole Mountains to look for the Amatola toad (Vandijkophrynus amatolicus), which had last been seen 12 years previously.
Prior to that sighting, a further 13 years had elapsed since the previous record, and there are only 20 records of this species in total since it was described in 1925. These historical accounts told of how hundreds of individuals would gather during the breeding season. Despite increasingly intensive searches of suitable habitat throughout the Amathole range in recent years these efforts went unrewarded. Once again, the Lost Frog search in 2010 failed to reveal any evidence of the toad, giving some credence to the idea that this species may have become extinct.
Then, on the 24 September 2011, it was with much excitement that Jeanne Tarrant and Michael Cunningham encountered this species at the same site it was last seen in 1998, adjacent to the Cathcart Road leading away from Hogsback. There is a small stream running through a wetland area below pine plantations. Slightly above the wetland, toad tadpoles and egg strings were found in shallow puddles, 2-15 cm deep, along a forestry track through the grassland, suggesting breeding of V. amatolicus at the site. That evening, at approximately 21:30 in cold (10°C) and windy conditions, a single female was discovered under a small pine log adjacent to the forestry track. This was the only adult found at the time, but it supports the identification of the tadpoles based on biotype and the form of the decaying egg strings. More importantly, this confirms that the Amatola toad is extant and breeding. The fact that it is breeding in shallow puddles on a dirt track in grassland, an abundant biotype in this area, suggests that the species is likely to be found elsewhere in the area. The single female had a large lesion on its dorsum. It is uncertain what the cause of this lesion is, but may be due to infection with ranavirus, which targets bufonids and may explain to some extent the disappearance of the species.
Searches for this species over the past 13 years, and particularly in recent years, may have been hampered by long-term drought in the Eastern Cape which may have inhibited breeding congregations previously observed in this species. As such, it may have been difficult to find adults. There has been significant winter rain in the region prior to our find.
Despite rediscovery, the likelihood that this species has experienced some form of population decline in recent years remains high. The species has been identified as being high priority for conservation research and monitoring. Confirmation that the species is extant should provide impetus for these conservation actions. Extensive surveys and monitoring must be conducted at all known sites as well as for potential new sites. Detection of V. amatolicus appears to be very dependent on climatic conditions and indicates that breeding occurs only after heavy rain and the breeding season may thus be short-lived. As such surveying needs to be conducted during the peak breeding season (September through December). The possibility of a ranavirus infection in the Hogsback population also raises the need to conduct such monitoring and ascertain presence of the disease. An assessment to determine population size and recommendations to adequately protect habitat, including both breeding and non-breeding sites is required. An immediate recommendation that can be made from this study is that cessation of forestry vehicle usage is implemented during the breeding season to prevent direct death of tadpoles in road puddles and breeding adults.
By Jeanne Tarrant
Jeanne Tarrant is currently at the African Amphibian Conservation Research Group in the School of Environmental Sciences & Development, Potchefstroom Campus, North-West University, South Africa.