The chain of ancient crystalline mountain blocks running from Kenya, through Tanzania, to Malawi and Mozambique is known as the Eastern Arc. Limited areas of evergreen forest exist on these mountains and these support numerous rare and restricted-range species, with many known from just one or a few sites. Despite some existing protection, the habitats for these species are severely threatened by agricultural encroachment and unsustainable exploitation.
The members of the Cambridge Tanzania Rainforest Survey 1990 visited the Ukaguru and East Usambara Mountains. Both were known to be of high conservation value, and the survey results further support this. The forests deserve protection on social, economic and scientiﬁc grounds, which are explained.
There were seven team members on Mount Mtai (5°00'S, 38°30'E) in the East Usambaras (7th July-14th August) and four in the Ukagurus (7°00'S, 36°30'E) (24th August-14th September). Both areas are Forest Reserves under the jurisdiction of the Forestry Division. Two ornithologists concentrated on mist-netting in both forests. Two members studied reptiles and amphibians at both sites, with an emphasis on nocturnal searching and sound-recording. In Mtai the three additional workers carried out a butterfly survey and a study of fish ecology, the latter in streams outside, but flowing from, the forest. In all the studies, a high priority was placed on locating poorly known, threatened and localised species.
Results indicate that Mount Mtai in the East Usambaras has a rich forest fauna, containing at least three threatened species of bird and many restricted-range amphibians and butterflies. Of particular importance are a butterfly, Celaenorrhinus sp., previously unknown to science, a threatened bird, Swynnerton's Forest Robin Swynnertonia swynnertoni, previously unknown from the Usambaras despite a great deal of omithological work there, and several forest butterflies and amphibians new to the Usambaras. Mount Mtai has at least a fifth of the remaining virgin forest in the East Usambaras. Forest is continuous from 300 m to 1100 m altitude, with a large area of low altitude forest, a poorly protected habitat in Tanzania. The conservation value of the Forest Reserve is unquestionably high.
The forest is being degraded by poorly regulated pit-saw logging. Proposals for its protection are made, the most urgent being the reduction or cessation of pit-sawing. Other proposals include posting additional Forest Ofﬁcers, extending the Forest Reserve boundary to cover the whole forest and marking the boundary with a tree cordon. Continued support for the IUCN/EC-supported East Usambaras Conservation and Development Project is also urged. The fish fauna of the Msimbasi river is apparently influenced by the presence of Maramba village, but this is of low conservation significance.
In the Ukagurus four forest bird species new for the mountains were recorded and both previously known threatened birds were found in reasonable numbers. All herpetological records were new, and included many rare species. Nectophrynoides minutus and Rhampholeon near platyceps, both found quite commonly, were previously known from single localities elsewhere. Many species appear to be limited to the small area of forest persisting below 1650 m, which requires urgent protection. The forest is clearly valuable on biological grounds, in addition to its local environmental importance.
The forest is under heavy pressure of degradation as it is the sole source of firewood to around 10,000 local households. Modest funds are required by the Wildlife Conservation Society of Tanzania to support a local initiative to plant woodlots for the future, encourage soil conservation measures and complete demarcation of the gradually eroding Forest Reserve boundary. A nearby softwood plantation could perhaps supply firewood in the interim – it is suggested that this possibility should be investigated.