Subproject E04

Prof. Dr. Eberhard Fischer, University of Koblenz-Landau, Rheinau 1, 56075 Koblenz, Germany

The influence of anthropogenous and natural fragmentation on diversity of flora and vegetation in upland and montane rainforests of Central and East Africa

Summary
In two isolated montane rainforests, the Kakamega-Forest and Mt. Kenya, the diversity of flora and vegetation in secondary and primary forests will be studied. Aim of the project is to study, how alpha-diversity is changed in different forest fragments by different anthropogenous and natural disturbance. Furthermore, it will be investigated, what the differences are between forests of different structure, fragmentation and distance to each other and which factors (structural parameters of habitat, abiotic influence) causes the spatial distribution of flora and vegetation. A further aim is to work out groups, that are suitable indicators for assessment of Central and East African forests.

Background
The montane rainforests of Central and East Africa are centres of diversity (White 1983) and floristically likewise well explored. The forests of Kenya are at least known concerning their basic structure (Beentje 1990), but only for a few areas, detailed vegetation monographs are available. The forests of Mt. Kenya (Bussmann & Beck 1995b) as well as the afroalpine vegetation of this mountain (Rehder et al. 1988) are studied phytosocilogically and data on regeneration and succession have been provided (Bussmann & Beck 1995a, c). The Kakamega-Forest has been subject only to few studies (Kokwaro 1988, Beentje 1990). Here, an inventory of plant communities is lacking, which will be supplied during the proposed project. A general lack of data concerns dynamic processes (succession, anthropogenous influence, natural disturbance and ist importance for maintainance of diversity). For the indicator-organisms to be studied, large amount of data is available for the genus Impatiens (Grey-Wilson 1980). A considerable lack of data, however, concerns structure and dynamics of epiphytic bryophytes and lichens and their communities. Especially bryophytes and lichens are promising as highly significant bioindicators.

Methods
A complete inventory of all occurring lichens, bryophytes, ferns and flowering plants will be made within the study area. For the analysis of vegetation, phytosociological relevés are necessary according to the method of Braun-Blanquet (1964). The quantitative analysis of vegetation also provides data of the population structure of selected indicator-species. All these data provide the basis for the calculation of alpha-diversity (Shannon-Index), beta-diversity (Sørensen-Index) and Evenness. The phytocenological data can be used as the base of vegetation maps with the help of satellite images as well as for an Geographical Information System (GIS).