11 - Saltmarshes and mangroves
from Part III - Coastal Systems
Summary
Synopsis
Saltmarshes and mangroves are wetlands formed in the intertidal zone of sheltered coasts, notably in bays, lagoons and estuaries. The vegetation of the two environments is quite different: mangroves are composed of a number of tree species, while saltmarshes are dominated by grasses and herbs. Mangroves are confined to the tropics and the lower latitudes of the sub-tropics, and are the dominant intertidal vegetation in these regions. Saltmarshes are found throughout the mid- and high latitudes and may also occur in some areas in the tropics. Plants of both ecosystems are salt-tolerant because they are frequently inundated by salt water and they are also adapted to growing under anaerobic conditions. The stress imposed by frequent inundation and waterlogged soils generally produces a gradient with one or two species dominating at lower levels and species richness increasing towards the high intertidal and beyond as the frequency of inundation decreases.
The movement of tidal waters across both mangroves and saltmarshes results in the development of tidal creek systems which act to move water, sediments and organic matter into and out of the systems. The vegetation of mangrove swamps and saltmarshes act to reduce wave action and the speed of tidal currents, thus promoting deposition of fine material. Vertical accretion in both environments ranges from a few millimetres a year to several centimetres and includes both organic material and mineral grains.
- Type
- Chapter
- Information
- Introduction to Coastal Processes and Geomorphology , pp. 325 - 368Publisher: Cambridge University PressPrint publication year: 2009
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