Mangrove swamps are a type of coastal wetland found on five out of seven continents between the latitudes 30? N and 30? S. Mangrove swamps are rich communities of both vegetative and animal species. The swamps are unique in the fact that they are a highly vegetated area found on the edge of marine coasts. The major vegetation in this area has adapted to absorb its water from the sea, and its oxygen from the air as opposed to the soil. This environment serves as home to many animal species, and home and nursery to many aquatic species.
Because this type of ecosystem requires such a unique environment, it is often in danger of disappearing. These communities are not only threatened by human development, but also by global warming and natural occurrences such as invasive species. These ecosystems are not only important because of their species diversity, but also because they serve as buffers between the land and sea. Discussion The majority of mangrove forests are found within 30 degrees of the equator in both the northern and southern hemispheres and appear on every continent except for Europe and Antarctica.
This means that they are located mostly in tropic climates though some have been recorded in more temperate regions (Warne, 2007). Climate has a large effect on the growth of mangroves because it determines the amount of available radiation and warmer temperatures. Precipitation in the richer mangrove forest is usually greater than 1250 mm (49. 2 inches) per year (“Mangrove ecology,” 2010). Historically, it is believed that the earliest mangrove swamps emanate from the Indonesian/Malaysian region.
This theory is believed to be true because this region is where these swamps are most frequently found (Lauri, & Gibson, 2000). The mangrove ecosystem evolved around 114 million years ago (“History/evolution of mangroves,” 2010) and spread through the unique floating propagules (buds) of the major mangrove species (Lauri, & Gibson, 2000). Ocean currents carried the floating buds during the early Cretaceous period to land in India, East Africa, and the Americas (“History/evolution of mangroves,” 2010). The parent material for mangrove swamps is very similar to that of any coastal wetland.
This is because mangrove swamps occupy the terrestrial edge between estuary wetland and marine waters. The soils are sandy with areas of heavy peat deposits created by copious amounts of plant litter. Mangrove swamps cannot form along cliffs because the mangrove tree species only grow on low gradient slopes (“Tour of mangrove,” 2008). The red mangrove species produce the peat deposits characteristic of the mangrove swamps. The peat is acidic and is capable of dissolving the limestone found underneath (“Ecology,” 2010). Mangrove swamps are named after their dominant vegetation.
The mangrove swamp is divided into three zones: the proximal zone, the middle zone, and the distal zone. The proximal zone (also known as the red mangroves) is closest to the waterfront. This area is subject to the effect of the tides. The main plant species found in this zone include Rhizophora apiculata and Rhizophora mucronata. These plants have adapted to the waters edge by forming long aerial prop roots that attach the plant to an otherwise loose sediment bed (“Tour of mangrove,” 2008). These waterfront plants are highly adapted for absorbing seawater and securing nutrients from the peat.
These mangrove tree species force positively-charged magnesium ions into their roots which repels the positively-charged sodium ions in the sea water, but the plant can still absorb the freshwater, forcing out the salt. The roots get their oxygen from the air through exposed roots rather than from the oxygen-poor soil (“Tour of mangrove,” 2008). On rockier coasts, species such as Avicennia Spp, and Sonneratia Caseolaris can be found. The middle zone (also known as the black mangroves) is located above the high tide.
These tree species absorb the salty seawater an then later excretes the salt through the leaves (“Tour of mangrove,” 2008). Some of the species included in the middle zone include Bruguiera gymnorrhiza, B. Cylindrica, Lumnitzera racemosa, L. littoralis, Ceriops tagal and Aegiceras corniculatum (“Mangrove ecology,” 2010). The tree species that are located in this zone specialize in the growth of pneumatophores. Pneumatophores, in botany terms, are aerial roots that specialize in gas exchange. These specialized roots allow the plants to receive oxygen outside of the oxygen-poor soil (“Tour of mangrove,” 2008).
Lastly there is the distal zone (also known as white mangroves). This zone is the farthest back and can vary based on the region. Excoecaris agallocha, Heritiera littoralis and Xylocarnus spp are the major species in this zone (“Mangrove ecology,” 2010). These species secrete salt through their leaves also but they do not have to rely on pneumatophores as heavily as plants in the other zones (“Tour of mangrove,” 2008). Mangrove swamps are home to many unique species. Mangrove swamps are very diverse because they are located in an environment that is partially aquatic, and partially terrestrial.
These wetlands are home to all different types of insect, crustaceans, fish, reptiles, and some mammals. Particular species that stick out in Indian mangroves include the mangrove crab (Scylla cerata), the fiddler crab, the Salmona butterfly, Hybloea puera (a moth), Telescopium telescopium (a mollusk), the mudskipper, and the royal Bengal tiger. The species Telescopium telescopium is an indicator species for the health of the Indian mangroves (“Mangrove diversity,” 2010). Mangroves, depending on where they are in the world, may have some more species indicative of those respective areas.
Climate change poses a significant threat to mangrove wetlands. Sea level rise is a direct result of the increasing global temperature due to climate change. Sea level rise forces the swamps to move inward toward the center of a landmass. This causes the swamps to shrink because they can only move inward so far until they reach an obstruction on the land. Currently sea level rise is increasing in some areas while decreasing in others. If it continues to increase in certain areas, there could be considerable loss over the next century (Gilman et al, 2006).
Management and conservation of mangrove swamps is a very difficult issue. These swamps are important not only because of their dense biodiversity, but also because they can serve as a protective barrier to the coast during strong storms and tsunamis. Because local governments hold the most power over unprotected mangroves, it is hard to protect them from human development. Many mangrove swamps are sacrificed for aquaculture, port facilities, saltpans, hotels, golf courses, and farmland (Warne, 2007). Another conservation issue is non-point source pollution.
Buildings and farmland surround many swamps, which drain into the freshwater tributaries surrounding mangrove wetlands (“Mangrove swamp,” 2010). Some natural threats to mangrove ecosystems include harmful algal blooms, climate variability, and invasive animals and plants. Climate variability is one of the most influential factors in mangrove survival. Climate change can affect both the average air and water temperature, which is important to mangrove plant and animal species in terms of growth and hatching. (“Mangrove swamp,” 2010) Sea level rise is a management concern that comes directly from global warming and recent climate change.