These ecosystems sustain billions of worms, protozoa, barnacles Balanus spp. These organisms in turn feed fish and shrimp, which support wading birds, pelicans, and the endangered Crocodile. Skip to main content. Contact Us. Mangrove Swamps. They usually form a green-to-red mass over the substrate.
They are also a filtering system for the land run-off and remove the terrestrial organic matter. They are very important habitats for many species of small fish, invertebrates and various epiflora and epifauna as well as larger birds. This is called a nursery function. The mangrove is a major producer of detritus that will contribute to offshore productivity in some seasons Coppejans [14].
Epiphytic micro-algae grow on the aerial roots of the trees and on the sediments. The algae are green Chlorophyta , brown Phaeophyceae , red Rhodophyta and blue-green Cyanophyta. The dense biomass on the aerial roots causes the water to remain on the pneumatophores; the lenticels are no longer functional and oxygen cannot penetrate into the roots.
For this reason, the bark regularly falls off the root. This process is called decertification. Vertical zonation along a single pneumatophore occurs, but there is also a zonation from the upper limit of the mangroves to the lower limit.
Several invertebrate species are found in the mangrove ecosystem. Macrobenthic species are commonly or occasionally present because they are migrating or because they are living in adjacent environments. Crabs are keystone species in the mangrove ecosystem. This means that the presence of this animal in the community makes it possible for many other species to live there. The crabs go through their larval stages in the water beneath the mangroves. When they are mature, they crawl up on the mangroves and feed on the leaves.
They can reach high densities and are crucial in the processing of leaf litter. Their burrowing activity modifies the micro-topography of the bottom and aerates the soil. This decreases the sulphide levels in the soil and positively influences the productivity of the trees. An example of a mangrove crab is the fiddler crab Uca lacteal. An important bivalve is the purple oyster Lopha frons. This species encrusts the pneumatophores and prop roots. When the tide is high, barnacles and mussels compete with the oyster for space on the roots.
Periwinkles also occur on the roots and stems, as well as on the shells of sedentary organisms attached on them. Snails are important in the turnover of the organic material. Other species that occur in the mangroves are tunicates, sponges, ants, hermit crabs, shrimps, fishes,… They are a source of nutrition for higher level predators.
Species that cannot tolerate changing saline conditions can survive in the forest. These species are sea stars, brittle stars and sea squirts. Predators are clapper rails, diamondback turtles, water moccasins, raccoons and killifishes. Bacteria and fungi initially break down the leaf litter decomposition.
In the tree canopy , vertebrate fauna and birds are common. Examples of birds are pelicans, wood ibises, herons, egrets and roseate spoonbills Hogarth, [8]. Mangroves are threatened in their existence by several causes, generally related to human activities. The main causes of mangrove loss are transformation of forests into economic land use such as aquaculture and agriculture, wood production, and urban infrastructure.
There is little chance of spontaneous mangrove regeneration in the deforested lands Coppejans [14] ; UNEP, [27] , due to increased wave agitation and soil erosion Winterwerp et al.
Non-native plant invasions may also restrict the re-growth of mangroves Romanacha et al. Several measures can be taken to preserve the mangrove ecosystem. The FAO Code regulates fishing techniques and eliminates destructive fishing gears.
The Code also provides guidelines for setting up management plans, for establishing no-take areas and involving fishermen and other users. Mangrove ecosystems can also be protected by creating National Protected Areas , World Heritage Sites or Ramsar Sites , that provide a legal protection framework.
Mangrove replanting projects have been undertaken in many places worldwide Friess et al. However, few replanting programs have proven successful. A first major issue is that many rehabilitation projects start planting before studying the original cause of mangrove loss to find out why there is no natural regeneration on site Lewis, [30]. Often essential conditions are not met because previous reclamations and interventions may have rendered the site less suitable for mangrove regeneration.
For example, compacted mudflats often have permanently saturated soil with poor drainage, leading to anoxic and potentially acidic soil Holguin et al. A second major issue is that species chosen for replanting may not be appropriate for the currently prevailing site conditions. Wright a multiplication problem in witch the product is between 0. Ineed figuring out how to work this problem!
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