[en] Landscape Ecological Survey of the Bipindi-Akom II ... - ITTO

and the vegetation resembles 'cloud forests' with many epiphytes and a canopy that reaches only
20-30 m. Another striking characteristic is the near complete absence of members of the
Caesalpiniaceae family, apart from typical mountain species like Monopetalanthus spp.,
Plagiosiphon sp., Hymenostegia sp. and Anthonotha cf. cladantha.
Along the main access routes and in the vicinity of the larger villages strongly degraded remnants
of evergreen forests (nOS 234 and 251) are found. In general the degraded vegetation is
characterized by the absence of a tree layer, except for a few residual forest trees, and the
abundance of pioneer species such as Haumania danckelmanniana, Harungana madagascariensis,
Megaphrynium macrostachyum, Xylopia aethiopica, and Musanga cecropioides. According to
Letouzey's map, the degraded areas are not differentiated by phytogeographical zone, i.e. littoral
Atlantic district and Biafran Atlantic district.
6.2 BOTANICAL DIVERSITY
A total surface of approximately 20 ha was inventoried during the present vegetation survey. A
total of 490 taxa have been identified to the species level, be longing to 76 families. The most
species rich families are: Euphorbiaceae (47 species), Caesalpiniaceae (43 species), Rubiaceae (29
species) and Annonaceae (18 species). All identified species are listed in Annex Va.
Identification in the field proved to distinguish some 530 'species', including several (small)
0" /. .groups ,groups of botanical species. The basis for the vegetation classification is the field identification.
The number of plant species encountered will surely increase with time when collecting is
continued and the skill of the collectors grows. It is therefore difficult to indicate the plant diversity
of the TCP area on the basis of these results. A large and species rich area like ours, needs
intensive collection to properly reveal species number, rarity and endemics. The second phase of
the Lul project will give some indications in this respect, while the forthcoming Ecoll project is
will be properly equipped to address the question of plant diversity.
6.3 VEGETATION CLASSIFICATION
The vegetation of the TCP research area can be divided into seven distinct plant communities.
Information gathered during the reconnaissance vegetation survey clearly indicates that within
each of the plant communities two or three variants can be distinguished.
A dendrogram representing the hierarchical vegetation classification is presented in Figure 6.2. The
hierarchy is based on similarities in species composition as given by the TWINSPAN analysis. A
division at a high level coincides with major differences in floristic composition. A division at a
lower level coincides with more subtle differences in species composition.
Not surprisingly, a distinction is made on the highest level between the floristic composition of
forest and shrub land. Of more interest is the distinction at the second level between the forest at
low altitudes and those on high altitudes. The flora of mountain forests (> 700 m above sea level)
proves to deviate strongly from that of lowland forests, apparently regardless of soil type and
former disturbances.
In Table 6.2 an overview of the vegetation types is presented. Each community is named after a
characteristic combination of occurring genera.
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