Habitat loss, due to human construction, has caused a serious decline in the Kihansi spray toad population. These unique toads now reside, and have been successfully bred, in captivity. After receiving medical attention to address infections and nutritional deficiencies, the toad population has increased to the point where they could be reintroduced to their natural habitat; provided researchers can be certain that, once reintroduced, the toads will continue to thrive.
Kihansi spray toad discovery
In 1996, construction began on a huge hydroelectric dam, located at the Kihansi River Gorge in southeastern Tanzania. The Kihansi spray toad species was discovered living near the bottom of a waterfall. These tiny toads thrived in the wetland caused by the forceful spray created by the vertical water fall flow.
In an article “It's Alive! Extinct Toad Lives on in Lab”, written for LiveScience.com, by Remy Melina, 21 July 2011, James Gibbs, a conservation biologist at the SUNY College of Environmental Science and Forestry (ESF) in Syracuse, N.Y. compared the wetland environment to living next to an open fire hydrant.
The dams’ construction significantly reduced the amount, and force of the waterfall spray in the toads’ habitat, resulting in a much drier area. The dryer habitat in itself was enough to cause a severe drop in the toads’ population, but the population suffered even more with the growth of the Chytrid fungus. Chytrid fungus is responsible for illness and population decline in amphibians worldwide.
Efforts to save the Kihansi spray toad
The Tanzanian government, in cooperation with the Wildlife Conservation Society, rescued several hundred members of the Kihansi spray toad (Nectophrynoides asperginis) population, in an effort to save the species from certain extinction. The rescued toads’ were sent to the Bronx Zoo in New York. The toads’ population continued its decline at the Bronx Zoo until some of the toads’ were transferred to the Toledo Zoo in Ohio. Researchers at the Toledo Zoo were successful in their efforts. The captive toads thrived and began to reproduce.
What makes the Kihansi spray toad so unique?
Kihansi spray toads have never been found living anywhere else in the world. These tiny four-legged vertebrates may well have the smallest habitat range in the world. Adult toads range in size from 1 to 1.5 inches in length and weigh only a few grams. They are yellow in color, and usually have gold and brown spots on their backs. Their skin is thin to the point of being translucent, and many of their internal organs can be seen through their stomachs.
Most amphibians lay eggs, but not the Kihansi spray toad. These animals are rare because the females give birth to live young. After birth, mothers carry their young on their backs. The toads are born with flaps over their nostrils, which may explain how they keep from drowning in the intense pressure of the waterfalls spray.
Insects and small invertebrates are their meal of choice, and the toads’ are very useful in keeping the insect population in their environment under control. They also serve as prey to larger animals that reside in or near their habitat.
Can Kihansi spray toads’ ever go home?
The Tanzanian government would like to bring the spray toads’ home; however, it is very important to insure that they will in fact survive if they are reintroduced to the wild. ESF scientists are working to create a stable enough environment for the toads’.
A man-made sprinkler system was installed in their habitat. The sprinklers were intended to mimic the natural spray from the waterfall; however, the damage done by the dam may be irreversible. Natural marsh and plants have already died off, and been replaced with weeds.
Pesticides in the river, caused by upriver agriculture are a serious issue. Scientists worry that the new toad population could be affected, suffer and ultimately fail in their newly restored habitat, due to high pesticide concentrations. Another dangerous and potentially lethal consideration is the continued presence of the Chytrid fungus.
Research is being conducted in order to determine the effect the fungus and pesticide will have on the Kihansi spray toads’, once they are reintroduced into their habitat. No one wants to reintroduce these amazing creatures into an environment that may not be able to successfully sustain them, so careful consideration and study is underway.
Decline of Kihansi spray toad is directly related to humans invading their environment
Human development, specifically the construction of a hydro-electric dam at the Kihansi River Gorge in southeastern Tanzania is responsible for the total extinction of the wild Kihansi spray toad. The Tanzanian government, in cooperation with the ESF and the Wildlife Conservation Society, are working diligently to save a small population of rescued toads that are still alive and thriving in a controlled lab environment. It is hoped that one day soon these amazing creatures can be safely returned to their natural, although slightly altered, habitat.
Sources:
“ESF Researchers Focus on a Tiny Tanzanian Toad: Kihansi spray toads extinct in wild”, 19 July 2011, ESF Office of Communications, ESF.edu, Accessed 26 July 2011
IUCN Red List of Threatened Species, “Nectophrynoides asperginis”, iucnredlist.org, accessed 26 July 2011
“Nectophrynoides asperginis Kihansi Spray Toad”, amphibiaweb.org, accessed 26 July 2011
Kelly Dupree - My love of animals, especially cats, and my interest in science has led to a serious passion to write well researched articles.
