Groundwater and the ecology of Avicennia marina (Forsk.)Vierh. and Rhizophora mucronata Lam. in Kenya.

Abstract

Mangrove ecosystems are composed of as well terrestrial elements as marine elements. It is this duality that makes the mangrove forest a unique ecosystem with a very high ecological and economical value for the tropical and subtropical coastal zones and their inhabitants. Ecologically, the mangrove forest can be considered as a nursery for many marine species like fishes, crabs, prawns, molluscs. Many bird species also search for shelter in the forest. Because of their partly above-ground root system, mangroves filter land runoff, increase sedimentation rates, protect the land from erosion and trap toxic substances in the sediments. Economically. the forest is very important for local communities that depend on the forest for fuelwood, charcoal, building poles (Kokwaro, 1985) and food (Saenger, 1983). Very recently the forest is also used as a site for human and industrial waste (Oteko, 1987). Tack (1997) already showed a clear relation between the distribution of mangroves and the groundwater flow. In this study different parameters of the forest are investigated in places showing a difference in groundwater flow.