Mgambo Forest Reserve: A biodiversity survey. - Eastern Arc ...

Mgambo Forest Reserve
EXECUTIVE SUMMARY
Mgambo Forest Reserve (FR) is located in the north-east of the main East Usambara
Mountain range, adjacent to the savanna plateau that reaches into Kenya. Mgambo FR covers
an area of 13.46 km 2 (1346 ha). It lies in the district of Muheza, Maramba Division, Tanga
Region and covers land approximately 10 km north from Maramba town, located on latitude
4 o 46’00” and longitude 38 o 45’15”. Mgambo FR was gazetted in July 1998, as delineated and
described on the Forest and Beekeeping Division map number. Jb. 2291. It was gazetted
primarily to protect the catchment areas supplying Bwiti, Mavovo, Mgambo and Daluni
villages. The region has an average annual rainfall of between 1000 and 1500mm per year,
falling principally from March to June although, in recent years, rain has been unpredictable
and low. Vegetation cover within Mgambo Forest Reserve has previously been recorded as
containing 1,295 ha of poorly stocked lowland forest and 51 ha of cultivation under lowland
forest (Johansson, 1996). The biodiversity survey within Mgambo FR shows that this has now
changed.
As part of the East Usambara Conservation Area Management Programme, (EUCAMP),
(formerly the East Usambara Catchment Forest Project), Frontier-Tanzania conducted a
biological survey of Mgambo FR between April and June 2002 for a total of 10 research
weeks. The systematic vegetation survey covered all parts of the reserve with a sampling
intensity of 0.25%, the zoological survey was focussed on 4 ten night trapping sites and 2 two
night sites. This report provides an inventory of the trees, shrubs, herbs, mammals, reptiles,
amphibians, birds and butterflies recorded during the survey. The report also describes
patterns of human disturbance within the reserve. The species richness, endemism and
ecological affinities of the taxa recorded are summarised in Table 1.
Table 1 Summary of biodiversity of taxa surveyed
Taxon Total no. of
species
% forest
dependent
No. of
non-forest
species
No. of
endemic
species
No. of
nearendemic
species
East Usambara Conservation Area Management Programme Technical Paper 59
v
No. of forest
dependent
endemics and
near-endemics
Trees and shrubs 128 5.0 29 1 12 2
Mammals 45 9.5 12 0 3 1
Birds 52 6.0 31 0 2 0
Reptiles 20 10.0 18 0 2 0
Amphibians 14 36.0 3 0 5 5
Butterflies 138 17.0 44 0 11 7
Total 397 n/a 137 1 35 15
Relative to other reserves surveyed by Frontier-Tanzania, Mgambo FR has a low floral
diversity and low to average faunal diversity.
In terms of flora, Mgambo FR is made up of patches of several different vegetation types
including dry lowland forest, riverine lowland forest, scrub forest, open woodland and
miombo woodland (Brachystegia sp.). A large proportion of species recorded within Mgambo
FR were categorised as non-forest dwelling (Table 1). Lowland riverine forest and some of
the lowland scrubby habitats were the most important habitats for endemic and near endemic
species, althouth the majority of the reserve suffers substantially from fire and overgrazing
disturbances. Only one plant species was identified as endemic to the Usambaras, this was
Cassia abbreviata .
Despite its small size, Mgambo Forest Reserve supports a high diversity of butterfly species
and several near endemic amphibian species. The reserve is home to 3 endangered and 5
vulnerable species according to the National Biodiversity Database (UDSM, 1997) and IUCN
categories.