Tuesday, February 24, 2009
Ecology:
A mangrove is a plant and a mangal is a plant community and habitat where mangroves thrive.
They are found in tropical and sub-tropical tidal areas, and as such have a high degree of salinity.
Plants in mangals are diverse but all are able to exploit their habitat by developing physiological adaptations to overcome the problems of anoxia, high salinity and frequent tidal inundation. There are many species of flora and fauna in the mangroves. Each species has its own capabilities and solutions to these problems; this may be the primary reason why, on some shorelines, mangrove tree species show distinct zonation. Small environmental variations within a mangal may lead to greatly differing methods of coping with the environment. Therefore, the mix of species at any location within the intertidal zone is partly determined by the tolerances of individual species to physical conditions, like tidal inundation and salinity, but may also be influenced by other factors such as predation of plant seedlings by crabs.
Nature, at the highest level of organisation, consists of the ecosphere which includes all living things (biosphere) together with non-living parts (atmosphere, hydrosphere, lithosphere). The next level is the biome which consists of groups of similar ecosystems over large geographic areas. Next is the ecosystem, which is a self-regulating community of organisms and their non-living environment.The community, consists of interacting populations (single-species groups) of all the different plants and animals in the area, which in this case, is the mangrove. Thus essentially, the mangrove community is the biotic part of this ecosystem.
Mangroves are very important because they supports a huge variety of organisms, including many interesting animals.
The mangrove is a very harsh environment to live in. The soil is very poor in oxygen and very unstable, which is why many of the trees have roots exposed to the air to take in more oxygen, and the roots often spread over a wide area to allow the trees to stabilise themselves on the soft mud. The bakau trees (Rhizophora spp.) above have prop and stilt roots to serve the above functions. The wood from this tree can be made into charcoal or furniture. The above image shows the prop and stilt roots of the bakau kurap (Rhizophora mucronata) and the propagules of bakau minyak (Rhizophora apiculata).
Another harsh condition faced by mangrove plants is that they will be soaked in salt water, which can remove water from the plant tissues through osmosis. To deal with this condition, plants like the Rhizophora, Bruguiera and the mangrove apple (Sonneratia alba) can selectively absorb only certain ions from the sea water through a process called ultrafiltration. But this process is not 100% effective, and some salt still gets into the trees, and will be removed by transpiration of the leaf surfaces or accumulated in old leaves. The sea apple has cone shape pneumatophores (i.e. upward extension of the root system).
Posted byAbigail Lim, Nicole lim and Angelyn Ong
living nature
1:45 AM
