Frontier Tanzania Environmental Research REPORT 110 ...

Kazimzumbwi Forest Reserve
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4.5.3 FOREST DEPENDENCY
Seventeen species (10%) recorded in Kazimzumbwi FR are considered to be forest dependent.
For the purposes of this study this was taken to include Brachystegia Forest and Riverine Forest
(including Swamp Forest), as Clarke and Robertson (2000) present these as main vegetation types
within Coastal Forests. Twelve of these 17 species were recorded through systematic sampling
and five through opportunistic collection.
The majority of forest dependent species were recorded within three or less plots, although the
near-endemic species Baphia puguensis was recorded in six of the 23 vegetation plots (26%). The
majority of forest dependent species were represented by only one individual. Ochna
mossambicensis (also near-endemic) was however represented by eight individuals, Baphia
puguensis by 10 individuals, Albizia gummifera by 11 individuals and Rinorea angustifolia by 37
individuals.
Large areas of Kazimzumbwi FR comprise habitats other than forests and thus the low number of
forest dependent species and consequently high number of ecological generalists is to be
expected. The dominance of ecological generalists in Coastal Forests in general is attributed to
the small size of forest patches and the fact that they are surrounded by open habitats and are dry
for large parts of the year (Burgess et al. 2000).
4.5.4 ENDEMISM
Thirty-two (19%) of the 172 species recorded in Kazimzumbwi FR are endemic to the Swahilian
Regional Centre of Endemism sensu lato , including two species (1%) that are endemic to the
Pugu Hills (and Gongolamboto in one case). Twenty-four of these 32 species were recorded
through systematic sampling and eight through opportunistic collection. Twelve species in total
are endemic to the Pugu Hills, including the two recorded during this work. The regional endemic
Dichapetalum edulis has previously only been recorded from T8 and Mozambique (Niassa
Province), thus the record in Kazimzumbwi FR (recorded within vegetation plots) represents a
range extension for this species.
Approximately half of the regional endemic species within Kazimzumbwi FR were recorded in
only one or two plots. Dialium holtsii and Manilkara sulcata were however recorded in eight
plots, Grewia conocarpa in nine plots, Manilkara sansibarensis in 11 plots and Diospyros
verrucosa in 12 plots. Almost half of the regional endemic species were represented by only one
or two individuals. Hyplocoelopsis africana was however represented by 24 individuals,
Diospyros verrucosa by 30 individuals, Manilkara sansibarensis by 35 individuals and Grewia
conocarpa by 43 individuals.
The family Rubiaceae contributes 14.3% of Coastal Forest regional endemic species, with many
others from the families Leguminosae, Euphorbiaceae, Acanthaceae, Annonaceae,
Asclepiadaceae, Cucurbitaceae, Poaceae, Vitaceae, Asteraceae and Verbenaceae (Clarke,
Vollesen & Mwasumbi 2000). Rubiaceae and Leguminosae were important families for regional
endemic species recorded in Kazimzumbwi FR, along with Sapotaceae and Tiliaceae. Diospyros,
Tricalysia , Grewia, Combretum and Ochna are genera containing many regional endemic species
in both Coastal Forests in general and Kazimzumbwi FR.
The majority of Coastal Forest regional endemic species are to be found in fire-excluded habitats,
thus not woodlands or grasslands (Clarke, Vollesen & Mwasumbi 2000). In Kazimzumbwi FR,
regional endemic species were recorded in all vegetation plots except one (Plot 1). This plot was
located in Wooded Grassland disturbed by fire as little as one year before the survey fieldwork.
Frontier-TanzaniaCoastal Forest Research Programme