|Vegetatie-ecologische studie van de mangrove langs de westkust van Gazi Bay (Kenia) = Vegetation-ecological study of the mangroves along the west coast of Gazi Bay (Kenya)|
Gallin, E (1988). Vegetatie-ecologische studie van de mangrove langs de westkust van Gazi Bay (Kenia) = Vegetation-ecological study of the mangroves along the west coast of Gazi Bay (Kenya). Ir Thesis. Rijksuniversiteit Gent - Faculteit van de Landbouwwetenschappen: Ghent. 157, 4 platen pp.
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VLIZ: Non-open access 247309
|Document type: Dissertation|
The mangrove area on the West coast of Gazi Bay has been studied during July and August 1987. Gazi Bay is situated along the Kenyan coast, about 40 km south of Mombasa. The area was studied by means of plotless measures and transects perpendicular on the coast. From these data we can conclude that this mangrove-area corresponds to the mangrove vegetation described in literature for the East African coast. Seven of the known mangrove species from Kenya have been found in Gazi (Avicennia marina, Bruguiera gymnorrhiza, Ceriops tagal, Lumnitzera racemosa, Rhizophora mucronata, Sonneratia alba and Xylocarpus granatum; Heritiera littoralis was not found in the area studied). The zonation pattern also agrees with data in literature. Replicas of tree leaves, made with transparent nail varnish, gave stomatal information (dimensions and densities). These results, combined with a few climatological parameters made it possible to calculate leaf transpiration during the day. This was done for three mangrove species (Ceriops tagal, Rhizophora mucronata and Sonneratia alba).At the same time, possible relations between transpiration, species and level in the zonation were studied. This part of the mangrove study proves that rather simple methods, necessary under tropical conditions, can give useful results. The third part of the study is dedicated to the algal communities on the pneumatophores of mangrove trees. In this association, known as the Bostrychietum, 58 pneumatophores of Sonneratia and Avicennia were sampled. Algae occuring on mangrove stems and on the mud were identified at the same time. In total 40 algal species were found in the mangrove vegetation. 16 belong to the Chlorophyta (green algae), 3 to the Phaeophyta (brown algae) and 21 to the Rhodophyta (red algae). The cover of each species on the aerial roots was estimated and the results were treated with 3 plant sociological computer programs : Twinspan, Decorana and PCA. These mathematical methods group associated algae and helps to understand the relation between the distribution of the species and the tidal emersion period.
- Algal community on the pneumatophores of mangrove trees of Gazi Bay in July and August 1987, more