The aquatic plant communities of the Lake Naivasha wetland, Kenya: pattern, dynamics and conservation

Abstract

The spatial and temporal patterns of the wetland plant communities at Lake Naivasha over the past decade, and the past five years in particular, are discussed in relation to the major controlling factors. The four communities are:- the emergent swamp, dominated by Cyperus species; the floating raft, dominated by the aliens Salvinia molesta and Eichhornia crassipes; the floating-leaved plants, represented only by Nymphaea caerulea; and the submerged angiosperms, consisting of three species of Potamogetons — P. pectinatus, P. schweinfurthii, P. octandrus — together with Najas pectinata. The major factors affecting their dynamics are:- water level changes which influence agricultural clearance, introduced crayfish Procambarus clarkii, and interactions between communities such as the physical effects of mobile floating rafts. The value of the different communities to the ecological and economic value of the lake is highlighted, and the possible damage from future activities discussed.