The rich flora and fauna of the East Usambaras

The East Usambara Mountains are located in Tanga region, in North-East Tanzania. The highest mountain peak reaches 1506 metres. The total area of the mountains is about 100 000 ha, of which about 45 000 ha is covered by forests. Some of these forests have been protected in forest reserves since the turn of the century and many go back to the 1930's and 1950's. Presently about 33,000 ha is within the forest reserves. This means that about 12,000 ha of forest is situated in public lands and remain outside formal, legal protection.

The East Usambara mountains belong to Eastern Arc Mountains, which is a chain of isolated mountains stretching in a great arc from Southeast Kenya to Southwest Tanzania. Geologically the mountains are very old - at least 100 mill. years. The total area of African rain forests diminished due to cold and dry periods which started about 2.5 mill years ago. The Indian ocean maintained the moist climate required by the rain-forests. The individual Eastern Arc Mountains became isolated from the large African rain-forests and finally from each other.

Through evolution new species were born and maintained; endemic species which can today be found only in East Usambaras or other isolated Eastern Arc mountains. The East Usambaras have been compared to Galapagos Islands with regard to diversity of endemic species.

There are lots of endemic plant and animal species in the Eastern Arc Mountains - there are more than 2000 plant species of which about 25% are endemic. Out of the 276 tree species 50 are endemic! The East Usambara mountains are the closest to the sea (only about 40 km) and due to moist climate the number of endemic species is remarkable. There are 16 tree species which can be found in the East Usambaras only. The forests of the East Usambaras have many rare species in all groups of animals, except mammals. High level of endemism are found amongst molluscs, amphibians and reptiles.

The genus Saintpaulia, or African violet as it is commonly known originates from North-East Tanzania. During the year 1892, Baron Walter von Saint Paul Illaire, then District Commissioner of Tanga Province, found wild plants with small blue flowers. The species was introduced to horticulture and since then it has enjoyed spectacular and ever increasing popularity as indoor plant. Nowadays, the East Usambaras is one of the few places where Saintpaulia still occurs - there are eight species growing in the area.