Tanzania is a country with a lot of special, unique and attractive living and non-living things. Some of these things are only found in Tanzania. These include: Tanzanite on the part of natural resources, Kihansi Spray Toads which attracted the attention of a lot of people from within and out of Tanzania that is the US and Europe.

Historically, it is believed that the first man lived in Tanzania at Olduvai Gorge several million years ago. Tanzania is an island of peace, it a home of refugees from East and Central Africa. It is a country with more than 120 tribes united with one language, Kiswahili. From North to South, East to West one can travel and speak to anybody without an interpreter unlike most of the neighbouring countries. What a beautiful country, a land of milk and honey!

Are you aware of a newly discovered butterfly species known as Charaxes Mtui only found in Tanzania? Before proceeding further with this species have something on Kihansi Gorge to appetise you my esteemed reader.

Kihansi gorge is a fraction of the Eastern Arc Forests located between latitudes 80 34i and 80 37i South, and longitudes 35o49i and 35o 51i East. The gorge is in Southern Tanzania on the Kihansi River, a tributary of the Kilombero and Rufiji Rivers and is approximately 150 km south west from Ifakara town.

The Gorge is deep and narrow lying just below the Kihansi Hydropower dam. It is created by the Kihansi River and is approximately 4 km long and 0.5 km wide. The gorge is steeply sloping, highly rocky, and of broken terrain which discouraged extensive human exploitation. The elevation ranges from 300 m to 1150 m.

The Kihansi Gorge became famous due to the discovery of the Kihansi Spray Toad (KST), Nectophrynoides asperginis, in the mid 1990s. Because of its unique biological and ecological characteristics, as well as its conservation status, the KST drew the special attention of the world conservation scientists. Efforts made to rescue the KST from extinction following the 98% destruction of its habitat as consequence of diversion of Kihansi River flow for power generation, made it seem as though the spray toad was the only species of importance in the Kihansi Gorge ecosystem.

The biodiversity of Kihansi gorge ecosystem is more than just the KST. Kihansi gorge is rich in biodiversity of flora and fauna some of which are either endemics of Kihansi Gorge only or of Eastern Arc Forests. Endemic fauna and flora of Kihansi Gorge Forest, Eastern Arc Forests The forest of Kihansi gorge contains typical Eastern Arc fauna of amphibians, reptiles and small mammals. Amphibian species of conservation concern present in the Kihansi Gorge include the toads of the genus Nectophrynoides, to which the famous N. asperignis belongs. This species which is put under IUCN category Critically Endangered was discovered to be new to science in 1996 by Prof. Kim Howell of University of Dar es Salaam.

Small mammals of conservation concern found in Kihansi Gorge forest are elephant shrews, while in the case of the reptiles, members of the family Geckonidae and Chameleonidae Primates: Kihansi gorge has diverse primate populations numbering up to seven species. The species of most conservation concern because of their limited distribution are the Procolobus pennantii (Iringa Red colobous) listed as Endangered on IUCN. Other species present in Kihansi Gorge are Colobus angoljensis (black and white colobous) and Bush baby.

Avifauna: Bird fauna of conservation concern, currently identified in Kihansi Gorge forest include Swynnertonis Robin, Uluguru Violet-backed Sunbird, Half-collared Kingfisher, Fuellebornis Boubou, White winged Apalis, Chapinis Apalis and Sharpeis Akalat. These species are globally threatened and / or of restricted range.

Kihansi Gorge accommodates a huge diversity of butterfly species. Two hundred and five species from nine families have been documented so far, where 18% belong to the family Hesperiidae, 5.4% Papilionidae, 7.3% Pieridae, 3.4% Danaidae, 5.4% Satyridae, 34.1% Nymphalidae, 7.8% Acraeidae, 18% Lycaenidae, and 0.5% Riodinidae. Among the 205 butterflies species, one species in the family Nymphalidae, the Charaxes mtui was discovered to be new to science in 2005 by Devolent Mtui.

Research and monitoring programme officer
Lower Kihansi Environmental Management Project / Tanzania Wildlife Research Institute. The Charaxes Mtui was collected in October 2005 at an altitude of approx 954 m a.s.L. This species was found to be new on 17th March 2006 at the African Butterfly Research Institute (ABRI) in Nairobi. According to Mr. Colin Congdon and Mr. Ivan Bampton, the butterflies specialists, the Charaxes Mtui is closely related to Charaxes martini helenae from Zomba, Malawi, as they happen to feed on the same food plant, Diospyros natalensis. A female of the species was raised on this plant (by Congdon & Bampton) and emerged in November 2006.

Other species of concern found in Kihansi Gorge are Celaenorrhinus sanjensis, Baliochila megadenta, Parosmodes moranti and Etesiolaus pinheyi. C. sanjensis is of restricted range and was only known to occur in Udzungwa National Park. According to Mr. Congdon this species was first categorized as vulnerable but with its extension to Kihansi Gorge; it is no longer vulnerable. B. megadenta was recently discovered in Udzungwa National Park above Sanje village. P. moranti was only known from the coast, inland to the Selous, and E. pinheyi was known from Amani in the East Usambaras and Kimboza forest, Morogoro. The record of these species from Kihansi is a considerable range extension.

The high diversity of butterfly species in the small sized Kihansi Gorge is wonderful but not surprising, because the gorge contains a huge diversity of flora which is the main food resource for butterflies.

Recent scientific reports on the monitoring of the impact of the diversion of the Kihansi River on vegetation of Kihansi gorge show a reduced growth rate and increased mortality rate of trees in the moist forest. Some plant species are critical food to some animal life and if they decline from the gorge it means decline of animal species depending on them for food, hence reducing species diversity.

Potential bio-indicators for Kihansi gorge ecosystem
The butterfly species termed as unique to the area are potential bio-indicators for Kihansi gorge ecosystem, because they have narrowly defined habitat requirements. Thus, if the habitat changes, it may no longer be suitable for them and they could disappear.

Plants: A large number of rare and endangered plant species occur in the moist forest of Kihansi gorge. These species are highly restricted Eastern Arc endemics, found only in forest patches in coastal eastern tropical Africa, or represent disjunct outlying populations of species more characteristic of other regions. Although they may belong to widespread species, isolated populations may be genetically distinct and so important for conservation.

At least four new species of plant have been identified to occur only in Kihansi Gorge. These are Kupea jonii, Kihansi lovettii, Sternadrium grandiflorum, and the critically endangered Coffea kihan-siensis. Other species endemic to Eastern Arc forest that are found in Kihansi gorge forest include Garcinia semseii, Cola scheffleri, Allanblackia stuhlmannii, Gigasiphon macrosiphon, Cephalosphaera usambarensis, Drypetes usambarica, Pterocarpus mildbraedii subsp. usambarensis.

All new species discovered in Kihansi gorge could be a potential future genetic resource that could useful to our food, medicinal industries and hence the country, global economy.

What is the issue: In the past, before diversion of the Kihansi River flow, Kihansi Gorge Forest used to be moist throughout the year. Dry conditions were never experienced in the gorge forest. The wetlands and the moist evergreen forest used to receive massive natural sprays from the Kihansi River falls.

Today, the wetlands are at least sustained by artificial sprays. The problem remains to forest areas used to receiving mists from the falls which are no longer available. Prolonged dry season is a threat to sensitive plant species of the moist forest for example C. kihansiensis and especially the new saprophytic plants which are adapted to wet and cool conditions.

Being shallow rooted and also considering the nature of the gorge soils (rocky & shallow), some big trees which are home for primates and birds are being observed falling day after day creating patches in the forest. Forest patches could increase plant diversity but on the other hand some birds and primates and other animal life could disappear before their existence is known.

What is to be done?
The Government needs to call for research to find out the ecological /genetic value of the 3 new plant species and the new genus.

The microclimate of the Kihansi gorge has changed and is continuing to change as a result of reduction of Kihansi River water flow. Since this change is irreversible, it has been recommended to transfer sample specimens of the new species/genus to a botanical garden to avoid their extinction before their value is known. Conserving Kihansi River catchment, will increase water flow to the dam, to the gorge ecosystem and help maintain the riverine forest.