Flora Biodiversity Assessment in Bonga, Boginda and Mankira Forest

common and dominant species. The associated trees are overlapping especially between
in Bonga and Boginda forest. The overlapping of species in Bonga, Mankira and Boginda
forest is expressed in Jaccard’s index and Sørensen's Index (Table 12).
Table 12. Biodiversity Indices of trees/shrubs and lianas greater or equal to 10cm dbh
Biodiversity Indices Bonga Mankira Boginda
Margalef 8.34 7.36 10.82
Menhinick’s 2.25 2.16 2.88
Shannon 3.13 3.06 3.27
Evenness 0.79 0.80 0.77
Simpson 0.03 0.04 0.04
Berger-Parker 0.08 0.09 0.13
Jaccard's index (site Boginda and Bonga forest) 52.33
Jaccard's index (site Boginda and Mankira) 57.14
Jaccard's index (site Bonga and Mankira forest) 40.24
Sørensen's Index (site Boginda and Bonga forest) 73
Sørensen's Index (site Boginda and Mankira) 72
Sørensen's Index (site Bonga and Mankira forest) 57
From the above Table it is possible to observe Shannon index between the three forests is
comparable, 3.13, 3.06 and 3.27, consecutively.
Index of Similarity according to Jaccard is a very simple mathematical expression for the
similarity of plant communities and is expressed by Community coefficient of Jaccard
(Mueller-Dombois and Ellenberg, 1974). It is based on the presence-absence relation
between the number of species common to two areas (or communities). Accordingly,
similarity of the three forests is estimated and the result is shown in Table 12 above. In
general, the similarity between the three forests is not that much strong. But Sørensen's
Index indicates stronger similarity than Jaccard’s Index. According to Mueller-Dombois
and Ellenberg, 1974 Sørensen's Index is mathematically more satisfactory as it includes a
statistically probability term and also it gives greater weight than Jaccard’s to the species
that recur in the two test areas than to those that are unique to either area (see the formula
below).
IS J
C
= * 100
Jaccard (=J) Based on presence of species only.
a + b + C
56