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Plant diversity in a Central African rain forest: Implications for biodiversity conservation in Cameroon
Figure 2.5 Correlation between altitude and the number of species recorded in 147 plots of 0.1 ha each.
The important value index (IVI) of the Caesalpiniaceae was high in most of the
vegetation types encountered and varied from 38.09 in lowland evergreen forest rich
in Caesalpinioideae to 14.01 in the lowland evergreen forest rich in Caesalpinioideae
with Sacoglottis gabonensis. In terms of species richness, there was a strong
significant negative correlation between the number of species recorded in the
various plots and the level of human disturbance (Figure 2.4) and a relatively weak
correlation with rainfall (F1, 145 = 10.094, R² = 0.099, P = 0.002), altitude (Figure
2.5), and distance from the sea (F1, 145 = 10.797, R² = 0.105, P = 0.001), or pH (F1, 145
= 7.200, R² = 0.073, P = 0.009).
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No of species
160
140
120
100
80
60
40
20
y = 0.0387x + 98.45
F1,145 = 21.318, R 2 = 0.188, P < 0.0001
0
0 200 400 600
Altitude (m)
800 1000 1200