Voorspellingen van de gevolgen van zeeniveaustijging op het mangrove-ecosysteem van Gazi (Kenia) = Predictions of the consequences of sea level rising for the mangrove ecosystem of Gazi (Kenya)
Defever, H. (2004). Voorspellingen van de gevolgen van zeeniveaustijging op het mangrove-ecosysteem van Gazi (Kenia) = Predictions of the consequences of sea level rising for the mangrove ecosystem of Gazi (Kenya). MSc Thesis. VUB: Brussels. 130 + referenties + 9 bijlagen pp.
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| Available in | Author |
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Document type: Dissertation
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| Keywords |
Mangroves
Temporal variations > Long-term changes > Sea level changes
ISW, Kenya, Gazi Bay [Marine Regions]
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| Abstract |
Results of the global warming are numerous; such as the rise of temperature, an increase of storm frequency and storm intensity and sea level rise. Based on a Digital Terrain Model combined with a recent vegetation map and actual sea level and tide amplitude, we tried to predict the impact of sea level rise on spatio-temporal dynamics of the mangrove vegetation of Gazi (Kenya). The DTM has been built on the basis of DGPS measurements, recorded during the fieldwork in the mangroves of Gazi in July and August 2003. Next, in a GIS environment we marked out five inundation classes on the basis of the DTM and simulations were executed of the rising sea level according to different scenario's. This information was then faced with the present vegetation map which was introduced as an extra layer in the GIS. From the results, given the reductionistic approach, we were able to conclude that in all cases, except for the maximum scenario, the surface of the mangrove-territory would increase. This is due to a quicker extend more inland of potential mangrove-territory with regard to land that 's going lost at the seaside due to the increasing sea level. Due to the very variable topography, the inundation classes will dynamically decrease or increase according to the script. The significant relation between inundation classes and the dominating standing-place o f a species - which has been proven by 3 of the 5 species regarded- shows that the frequency of inundation is an important factor for the vegetation zonation. Due to this we expected that the species with a particular preference for a certain inundation-grade, will decrease or increase their superficies directly proportional to the concerned inundation class. Two species show a lesser connection between appearance and inundation class. We presume that for these species the frequency of inundation (and the combined factors such as salinity) play a secondary part and that other elements such as interspecific competition, substratum, predation, are more important. Based on this case study we can conclude that we have to reject the simplistic idea that sea level rise in all cases would be devastating to mangroves. It is also difficult to extrapolate information from this study to other locations because of the very specific conditions of each site which influences the impact of sea level rise on mangroves in a site specific way. |
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