Jozani biodiversity inventory report 2002 - Coastal Forests of Kenya ...

large study area and time constraints transects were spaced to cater for both habitat and spatial
distribution. Also due to a large gap in the knowledge of small mammals, amphibians and
invertebrates in the study area the survey team concentrated much of its effort on the currently
least known taxa and species. For the large and medium sized mammals which have been studied
before and/or there is a substantial amount of information, the existing literature was used to
provide information. Species diversity was calculated using the Shannon Weaver Index H' :
nlog
n − fi log fi
i=
1
H'
=
n
Where k = number of categories, f i = number of observations in category i, n = sample size.
The maximum diversity which could be attained in the area was calculated using the expression:
H' max = logk
k
Where H' max is the maximum possible diversity for a set of data consisting of k categories. H' tests
abundance equality among k categories and is affected by the distribution of data and the number
of categories. H' max is the highest diversity which can be calculated from a set of data consisting
of k categories (Zar, 1996).
Table 3: Description of transects used to sample plants, small mammals, reptiles, amphibians and
invertebrates in Jozani - Chwaka proposed National Park, Zanzibar. GPS coordinates (using
Garmin GPS 12x) for each transect were taken for future reference
Transect
SN
Name
1 Wangwani (Evergreen
scrub forest/Coastal coral
rag forest)
GPS
S 06° 13.552'
E 039° 24.642'
Description
Natural forest close to salt marshes, tall
trees up to 10-25m high. Canopy cover
c.60-100% in some areas with strata. Dry
leaf litter cover 60-100%. No signs of
harvesting. Soils fairly deep, dark brown.
Coral rag conspicuous in some areas.
Salt marsh grassland
2 Wangwani (wooded
grassland)
S 06° 13.563'
E 039° 24.765'
Open salt resistant grassland with almost
100% cover and few emergent shrubs.
Typha and mangroves downstream. High
water table, black sandy-loam on top of
rocks and in some places the sub surface is
composed of sand
Annona senegalensis bushes predominant
c.4-4m high. Grass cover 85% wood
vegetation cover 10-15%. Coral rag
emergent common and conspicuous. Soil
dark brown fairly deep mixed with coral rag
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