Biodiversity of the East Usambara Mountains

The Eastern Arc mountains are a group of mountains that run in an arc mainly in eastern Tanzania. They begin as the Taita hills in Kenya and end with the Udzungwa mountains in southern Tanzania. Due to their extremely high diversity of flora and fauna, many species of which are found only in these mountains, the Eastern Arc has achieved the nickname of the Galapagos of Africa. Three of the mountain blocks, Udzungwa, East Usambara and Uluguru, are considered the most important for conservation of biodiversity due to their extraordinary richness in species of plants and animals.

Nestled closest to the Indian Ocean, the East Usambara mountains are forested from the lowlands up into the highlands. Prior to the 1990s, the forest was under heavy pressure by a variety of human activities, but since then numerous patches were gazetted as forest reserves by the East Usambara Catchment Forest Project. To further conservation efforts and bring national and international attention to this unique area, the government of Tanzania created the first nature reserve in the country. Amani Nature Reserve was established in 1997 and it comprises much of the forest in the lowlands and highlands in the southern section of the East Usambaras.

The forests of Amani Nature Reserve vary in structure and composition as one travels upward from Muheza, being drier near Sigi and much wetter on the plateau. At least 25-30 per cent of the flora is endemic to the Eastern Arc forests (many of which may occur only in the East Usambaras), some including conspicuous trees like Cynometra brachyrrhachis and Cola usambarensis whilst others are as small as the well known house plants, African violet (Saintpaulia species).

The forest habitat provides a home for numerous animal plant groups, including many insects and other invertebrates like millipedes and snails. Larger mammals are few relative to other African forests, but specialities like the black and rufous elephant shrew (Rhynchocyon petersi) exist; smaller mammals are more diverse and at least one shrew species has been an interesting recent discovery.

Bird life is rich with almost 350 species so far recorded from most habitats that occur from the foothills to the montane forest; 12 birds found in the East Usambaras are on the globally threatened bird list.

Reptiles, while numerous in forms and colours, are represented by over 30 species of snakes and several chameleons, including the terrestrial pygmy leaf chameleons and the larger, arboreal three-horned chameleons. Amphibians are as varied as their reptilian relatives, with many species of tree frogs and some strange ground-dwelling frogs and worm-like caecilians.

Insects come in all forms and colours, with many being found only in these mountains. Moths and butterflies are better known, whilst many other insects remain poorly known and probably have yet to receive a scientific name.

Poster: N.J. Cordeiro
© East Usambara Conservation Area Management Programme (EUCAMP) / Amani Nature Reserve

Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: S. Valentine
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro	Photo: N.J. Cordeiro
Photo: N.J. Cordeiro