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Impacts of deforestation of west African mountains on biodiversity
Stříbrská, Eliška ; Hořák, David (advisor) ; Reif, Jiří (referee)
The high rate of deforestation is a global problem with negative impacts on species biodiversity and it also contributes to global and local climate changes. This problem is much more urgent in hotspots of biodiversity and endemism like west African mountains. Moreover, these locations are now recognized as the most fragmented and the most deforested mountains on the African continent. Impacts on local organisms is mostly negative. The organisms are facing habitat loss and the inability to migrate between the isolated regions. The bond between associated animals and plants, that are life depend on each other, is being broken and the whole ecosystem is being changed. In general, the ecosystem is less stable and all these changes make deforestation a chain reaction. Although there are some positive impacts on the biodiversity too, it does not influence the endemic species. It has more positive consequences for the generalist species occupying wide range of habitats and utilizing various food resources. Local communities are also facing the impacts of the ecosystem changes, their lives are negatively influenced by longer and more intensive periods of drought, landslides and they are not able to rely on the supply of the forest products. To be able to change current situation, financial support and...
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Diversity of bird species along elevational gradient on Cameroon mountains
Dubský, Marek ; Sedláček, Ondřej (advisor) ; Reif, Jiří (referee)
The aim of this thesis is to describe the changes of bird species diversity along elevation gradient on six mounts in Cameroon and nearby Bioko island. The results of the analyses confirm most of the defined hypotheses, especially they show that species diversity declines with altitude and rises with area. The absolutely highest diversity was detected on mount Kupé and mount Cameroon, but above 2100 m above sea level mounts Oku and Manenguba are the most diverse. Other analysis showed that the biggest changes in beta diversity of bird assemblages along altitudinal gradients are on the lowest elevational belts which are on the edges of a degraded habitats and continuous undisturbed forests. Other important changes in bird assemblages happen around altitude 1200 m, where the assemblages of lowland rainforest change to assemblages of mountain forest. Analyses of affinity of bird species to forest habitat showed that the most affined assemblages to the forest are those found on mounts Kupé and Rata. On the other hand bird assemblages on mounts Manenguba and Oku are the one of least affined to the forest biotope. Analysis of habitat generalism and specialism did not show the expected outcome and for clearer results the design of analysis needs to be improved. The results of this thesis contribute to a...
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Diversity and abundances of birds along altitudinal gradients of Cameroon Mountains
Dubský, Marek ; Sedláček, Ondřej (advisor) ; Reif, Jiří (referee)
The aim of this thesis is to describe the changes of bird species diversity along elevation gradient on six mounts in Cameroon and nearby Bioko island. The results of the analyses confirm most of the defined hypotheses, especially they show that species diversity declines with altitude and rises with area. Cluster analysis shows the similarity of individual mountains in particular altitude zones. Despite the original hypothesis, mount Cameroon is found to be most similar to mount Kupé, although high mountain assemblages of mount Cameroon and Bioko island are very alike as well. The absolutely highest diversity was detected on mount Cameroon and mount Kupé, but above 2100 m above sea level mounts Oku and Manenguba are the most diverse. The results of this thesis contribute to a clearer notion about factors influencing species diversity; however, more thorough data (particularly from mount Nlonako) and data extension for e.g. bird abundance would enrich the study and it would enable us to perform more detailed diversity analysis, especially an analysis of competition relationship among species. Key words Species diversity, Cameroon, bird assemblages, elevational gradient
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