Salinity fluctuations in the mangrove forest of Gazi Bay, Kenya: lessons to take for future research

Abstract

Studies on mangrove ecosystems that deal with the interaction of organisms and their environment very often draw conclusions based on only a restricted number of soil water salinity measurements. As inundation by salty water is the most typical characteristic of the mangrove environment, the authors addressed the temporal and spatial fluctuation of soil water salinity at seven locations in the mangrove forest of Gazi Bay, Kenya. As a pilot study, the research team measured soil water salinity twice a month, at neap tide and at spring tide, during one year. It can be concluded that the soil water salinity in mangrove forests can be highly variable in time as well as in space and depends on a complex interaction between inundation frequency, canopy closure, fresh water input and soil texture. Mangrove researchers should therefore pay attention to the differences in local site conditions inside the mangrove forest and conduct salinity measurements that cover the temporal and spatial fluctuations before drawing conclusions on the relationship to this environmental condition.