Nectophrynoides asperginis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA AMPHIBIA ANURA BUFONIDAE

Scientific Name: Nectophrynoides asperginis
Species Authority: Poynton, Howell, Clarke & Lovett, 1999
Common Name(s):
English Kihansi Spray Toad

Assessment Information [top]

Red List Category & Criteria: Extinct in the Wild ver 3.1
Year Published: 2009
Date Assessed: 2009-05-17
Assessor(s): Channing, A., Howell, K., Loader, S., Menegon, M. & Poynton, J.
Reviewer(s): Hoffmann, M. & Angulo, A.
Justification:
Listed as Extinct in the Wild because no self-sustaining population exists in the wild, but the species survives in captivity.
History:
2006 Critically Endangered (IUCN 2006)
2006 Critically Endangered
2004 Critically Endangered

Geographic Range [top]

Range Description:This species was only known from the Kihansi Falls, in the Kihansi Gorge, in the Udzungwa Mountains, eastern Tanzania, at 600-940 m asl. Its global range covered an area of less than two hectares around the Kihansi Falls, and searches for it around other waterfalls on the escarpment of the Udzungwa Mountains have not located any additional populations (Channing et al. 2006).
Countries:
Regionally extinct:
Tanzania, United Republic of
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: It was formerly abundant in a tiny area, with a population of around 17,000 animals. Reports indicate that the species fluctuated naturally in its population size. The population appeared to be at a high in May 1999, dropping to lower numbers in the course of 2001 and 2002 [total population estimates oscillated at around 11,000 individuals up until March 2002; see Channing et al.(2006)], and at a high again in June 2003 [a total population estimate of 20,989 individuals; Channing et al. (2006)]. However, subsequently the population went into steep decline, and by mid-January 2004, only three individuals could be seen and just two males were heard calling. There were a few records of calling animals during the rest of 2004, and an unconfirmed report from May 2005 (CBSG 2007), but there are no records of any individuals since, despite surveys, and the species is now considered to be Extinct in the Wild.

Habitat and Ecology [top]

Habitat and Ecology: It lived only in soaked herbaceous vegetation in the spray zone of the Kihansi Falls. It breeds by internal fertilization, the females retaining the larvae internally in the oviduct until little toadlets are born. Clutch size varies from 5–13 offspring (Channing et al. 2006).
Systems: Terrestrial; Freshwater

Use and Trade [top]

Use and Trade:

There are no reports of this species being utilized.

Threats [top]

Major Threat(s): The serious decline and extinction of this species appears related to the Lower Kihansi Hydropower Project, involving the construction of a dam in 2000 upstream on the Kihansi River, which cut off 90% of the original water flow to the gorge, thereby hugely reducing the volume of spray, particularly in the dry season, as well as altering the vegetational composition. An artificial gravity-fed sprinkler system was set up to mimic the natural spray of the Kihansi ecosystem with the remaining water flow. Unfortunately, the sprinkler system was not ready by the time the water was cut off in 2000, and by the time the sprinklers came on nine months later the ecosystem had already dried up (see Krajick 2006). Later, during the dry season in 2003, the artificial sprinkler system failed for a while. Around this time, the fungal disease chytridiomycosis was confirmed in dead animals of this species, and this disease is probably responsible for the final population crash. It is possible that the drought caused by the failure of the sprinkler system resulted in stress to the animals that rendered them susceptible to the disease. There are also reports that the 2003 crash coincided with a brief opening of the dam's floodgates to flush sediments; tests showed that these contained pesticides used in maize farming operations upstream, in concentrations sufficient to kill the toads (Krajick 2006). The impact of predation by safari ants (Dorylus sp.) and crabs (Potomonautes sp.) is unknown (Channing et al. 2006).

Conservation Actions [top]

Conservation Actions: It was not known from any protected areas. Sufficient minimum bypass flow from the dam is required to maintain the spray habitat. An artificial sprinkler system is in place, and this is especially important in the dry season. Captive breeding is ongoing in Toledo and New York Bronx Zoos. The captive populations have fluctuated as husbandry problems have been encountered and addressed (animals were initially plagued with various infections and nutritional deficiencies); ex situ colonies were comprised of a total of 460 individuals on February 12, 2007 (CBSG 2007). Reintroduction efforts should be preceded by an assessment of the species' habitat status and efficiency/operationality of the artificial sprinkler system currently in place.
It is listed on CITES Appendix I.

Bibliography [top]

CBSG (IUCN/SSC). 2007. Kihansi Spray Toad (Nectophrynoides asperginis) Population and Habitat Viability Assessment: Briefing Book. CBSG, Apple Valley.

Channing, A. and Howell, K.M. 2006. Amphibians of East Africa. Edition Chimaira, Frankfurt am Main.

Channing, A., Finlow-Bates, K.S., Haarklau, S.E. and Hawkes, P.G. 2006. The biology and recent history of the Critically Endangered Kihansi Spray Toad Nectophrynoides asperginis in Tanzania. Journal of East African Natural History 95(2): 117–138.

Channing, A., Menegon, M., Salvidio, S. and Akker, S. 2005. A new forest toad from the Ukaguru Mountains, Tanzania (Bufonidae: Nectophrynoides). African Journal of Herpetology 54: 149-157.

IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: www.iucnredlist.org. (Accessed: 3 November 2009).

Krajick, K. 2006. The lost world of the Kihansi toad. Science: 1230-1232.

Poynton, J.C. 1998. Tanzanian bufonid diversity: preliminary findings. Herpetological Journal: 3-6.

Poynton, J.C. 2003. Altitudinal species turnover in southern Tanzania shown by anurans: some zoogeographical considerations. Systematics and Biodiversity: 117-126.

Poynton, J.C., Howell, K.M., Clarke, B.T. and Lovett, J.C. 1998. A critically endangered new species of Nectophrynoides (Anura: Bufonidae) from the Kihansi Gorge, Udzungwa Mountains, Tanzania. African Journal of Herpetology: 59-67.

Quinn, C.H., Ndangalasi, H.J., Gerstle, J. and Lovett, J.C. 2005. Effect of the Lower Kihansi Hydropower Project and post-project mitigation measures on wetland vegetation in Kihansi Gorge, Tanzania. Biodiversity and Conservation: 297-308.

Zippel, K. 2005. Zoos play a vital role in amphibian conservation. http://elib.cs.berkeley.edu/aw/declines/zoo/index.html 26 July 2005.


Citation: Channing, A., Howell, K., Loader, S., Menegon, M. & Poynton, J. 2009. Nectophrynoides asperginis. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 28 August 2014.
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