Introduction

Minziro Forest Reserve is located in Bukoba District, Kagera Region, north western Tanzania at 31º 30’ East, 1º 05’ South (Map 1, Map 2). The reserve was gazetted in 1947, covering an area of 24,841 hectares contiguous with Malabigambo Forest Reserve in Uganda. Of the 24,841 hectares of reserve, 19,000[1] hectares can be broadly classified as Baikiaea-Podocarpus seasonal swamp forest (Davenport & Howard 1996). The remainder of the reserve is seasonally flooded grassland with pockets of predominantly Acacia polycantha woodland and papyrus on the river edge¹.

The general area is flat with small rocky outcrops, the Kitengule / Buhingo hills 2 km east of the reserve at 1312m representing the highest point in the immediate area (map 2). The forest reserve is at an altitude of 1125m to 1140m with Minziro village situated on a hill in the centre of the reserve. As much of the grassland is seasonally flooded, settlement and agriculture are restricted to ground above 1140m in most areas. Coffee (robusta) is the major cash crop while cassava, bananas and beans are the staple food crops. The area is greatly influenced by the Kagera River that flows 7 km south of the reserve, meandering north to form the eastern boundary of the forest reserve (map 2). The Kagera River also forms the western boundary of Kikuru and Kyenshenja Forest Reserves comprising 1,700 hectares[2] of forest cover on rocky and undulating ground to the east of Minziro (map 2). Rainy seasons are October, November and between March and May. The lake zone receives 1400-2000mm per year, however Minziro receives an average of 600-1000m per year (Pamba, 1999). In the past, legal commercial logging occurred under licence, the royalties were collected by Bukoba District, and were then sent to the treasury in Dar-es-Salaam. According to by-laws, cess is paid to the District (Pamba, 1999). Illegal harvesting of Podocarpus has been reported for shipment to Bukoba. A considerable amount of Podocarpus was taken out in the past and thus few large Podocarpus remain in Minziro (see Tassen, 2000).

At 24,841 hectares, Minziro represents one of the largest forest reserves in the country. The forest ecosystem is unique to Tanzania however contains few endemics, most of the flora and fauna being represented in eastern and western forest types. One notable endemic is the swamp podocarpus now recognised as a distinct species Afrocarpus dawei (Rodgers, in press). White describes the forest in his Vegetation of Africa:

The forests occurring 1200 m asl on alluvial deposits at the mouth of the River Kagera are unique in Tropical Africa in being composed of an equal proportion of lowland (mainly western Guinea-Congolian) forest species and highland (afro-montane) forest species. Undisturbed forest is dominated by the GC Baikiaea insignis and the AM Afrocarpus dawei. Other GC species are: Canariun schweinfurthii, Klainedoxa gabonensis, Maesopsis eminii, Pseudospondias microcarpa, Pycnanthus angolensis and Symphonia gloulifera. Main AM trees are: Apodytes dimidiata, Croton megalocarpus, Ilex mitis, Podocarpus latifolius, Strombosia scheffleri, Trichocladus ellipticus and Warburgia salutaris.

Recent botanical surveys of Minziro Forest Reserve have been carried out on behalf of the Crossborder Biodiversity project by Roy Gereau (Missouri Botanical Gardens) and a team of botanists from the Tropical Botanical Training Programme in Tanzania. These surveys have found at least seven species of special interest. Among these, 3 species are new to Tanzania and 3 new genera to Tanzania. A species of the Genus Turraea has also been collected in the western part of Minziro. Not previously known from within East Africa, this may be an endemic Tanzania or the East Africa region (Gereau, pers comm).

Twenty three percent of the Bird species (n=58) are Guinea-Congo biome restricted (map 1) (58 spp from a total of 245 spp. The remaining 187 species being widespread forest and non-forest species, see appendix I,II). This biome stretches from Senegal in west Africa to Minziro, Mahale and Rubondo forests in Tanzania and the Sango-bay forests in Uganda. In Kenya the easternmost outliers of Congo basin forests are Kakamega and Nandi forests in western Kenya (Bennun et al, 1999) (White indicates western Kenya within the Guinea-Congo/Sudania regional transition zone xii). In total this biome encompasses 26 countries and 278 bird species (Fishpool, 1997). Of these 278 species of birds, only 58 (21%) occur in Tanzania, outlining the position of these forests on the eastern fringe of this biome. The uniqueness of the biological assemblages in Minziro make this forest reserve an important ‘protected area’ and a major component of the national biological diversity of Tanzania.

Although the forest contains many bird species which are unique to Tanzania, Minziro Forest Reserve qualifies for Important Bird Area status due to the presence of 1 globally threatened species, which occur in habitats other than forest in and around the forest reserve (Map 2). The 2,174[3] hectares of grassland in Minziro is an important component of the reserve, providing wintering habitat for the globally threatened Blue Swallow Hirundo atrocaerulea (IUCN: Vulnerable, (See page 7, species of special interest). The papyrus that fringes the river bank and forms small swamps near Nyakabanga may provide habitat for a second globally threatened species, Papyrus Gonolek Laniarius mufumbiri, a papyrus endemic found throughout the Kagera River (IUCN: Near-threatened. See page 8, Species of special interest).

The forest reserve seasonally supports populations of Buffalo and Elephant. The race of Western pied Colobus Colobus polykomos; adolfi-friederici is confined to the Sango-bay forests (Rodgers, 1981). Minziro is the only locality in Tanzania where Grey-cheeked Mangabey Lophocebus albigena has been recorded. Due to the uniqueness of the avifauna it is likely that Minziro Forest Reserve contains many other west African forms which are unique to Tanzania.

The UNDP / GEF Crossborder Biodiversity Project aims to reduce biodiversity loss at specific crossborder sites in East Africa. The project concentrates on forest reserves within three districts in Tanzania, each chosen for their specific forest ecosystems which cross international boundaries. Minziro Forest Reserve is the focal point within Bukoba District, were the Biodiversity project is focusing its efforts to reduce illegal extraction of timber whilst meeting the socio-economic needs of local people.

In order to make an accurate assessment of the focal area, a current appraisal of the flora and fauna is required to provide baseline data. For logistical reasons certain taxa are chosen as biological indicators. Of these birds ‘are’ the best known, most easily studied and are relatively conspicuous. In order to make an accurate appraisal of the forest reserve, a team of three trained ringers, two Tanzanian trainees and two volunteers were assembled to carry out a two week assessment of the forest and surrounding areas. This was done using standard mist netting, observation and sound recording. In addition, previous ornithological visits by Baker & Hirslund (1984), Baker et al (1987), Baker & Baker (1993) and Moyer (1999) were used to compile as complete a species list as possible.

[1] Although the gazettment notice gives a figure of 24,841, this includes grassland. The figure 19,000ha is measured using 1:50,000 topographic maps.

[2] Area measured from 1:50,000 topographic map.

[3] Area measured using 1:50,000 topographic map.