Biology of Mangroves :: Research Essays Term Papers

Biology of Mangroves One of the most unique and least understood environments found in nature is that of the mangrove. This ecosystem is found at the junction between land and sea. Author, Loren Eiseley (1971) wrote vividly about his encounter with a mangrove forest in the book The Night Country: A world like that is not really natural. Parts of it are neither land nor sea and so everything is moving from one element to anotherÃâ€"Nothing stays put where it began because everything is constantly climbing in, or climbing out, of its unstable environment. The actual word à «mangroveà ­ can be used in two ways. It can refer to an individual species of plant or it can indicate a group or forest of plants that contains many species (Figure 1). To determine what constitutes a mangrove species many aspects are considered including: (1) air temperature within a certain range, (2) mud substrate, (3) protection, (4) salt water, (5) tidal range, (6) ocean currents and (7) shallow shores. To clarify, each of these aspects will be considered in turn. The best mangrove development has been found to occur only when the average air temperature of the coldest month is higher than 20 degrees Celsius and where the seasonal range does not exceed ten degrees. Most extensive mangroves are associated with muddy soils along deltaic coasts, in lagoons and along estuarine shorelines. In order for mangroves to survive a protected coastline is essential as mangrove communities cannot develop where high levels of wave action prevent the establishment of seedl ings. In terms of salt water, there is increasing evidence that most mangroves have their optimal growth in the presence of some additional sodium chloride. The tidal range plays an important role in mangrove development. The greater the tidal range, the greater the vertical range available for the community. Also for a given tidal range, steep shores tend to have narrower mangrove zones than do gently sloping ones. Another aspect of mangrove communities is ocean current. The currents are essential since they act to disperse the mangrove propagules and distribute them along the coasts. The need for a shallow shore is the last major aspect of mangrove forests. This is apparent when considering that seedlings cannot become anchored in deep water and that the mangrove requires a large proportion of its body to be above the water (Hutchings and Saenger, 1987). Mangrove forests are established in various regions of the world and one of the most prominent regions is the continent of Australia.