Ecology in Mangrove

Along the Hong Kong Deep Bay or some mud flats where has a low salinity, mangroves are usually been found. And there has several common species in Hong Kong, for example, Acanthus ilifolius, Kandelia candel etc. These species are usually located at the front of the mangrove area near the sea. Therefore when the tide comes, they are usually completely immersed and come out during the low tide. Beside those near the sea, there also has some near t

In order to survive in the mangrove, there are several adaptation of the fauna species. Firstly, they all contain a very hard shell such as periwinkles so as to prevent from desiccation. Besides, the some gastropods has the muscular foot. Thus, they can stabilize on the substratum once there has wave action. Crustaceans are also common in the mangrove. They burrow in loose substrate to provide a shelter from predators, besides that, those hole can also be a breeding place. Some of them would hide in their holes and feed by sifting through wet sand, as a result, you can see there has a lot of round ball of sand left on the muddy ground of the mangrove as they left them after feeding. In fact, these kinds of activities are not only benefit to themselves. For example, these movements can facilitate the diffusion of oxygen into the mud more easily and benefit other animal species.

This explanation of this is not difficult. It is a common sense that there is more dangerous for a plant to grow near the seacoast. For example when the high tide comes, the plant¡¦s truck or canopy may be all covered by the sea affect its normal respiration or transplantation. Besides, the plants growing there also need to face the risk of being washed away by the seawater due to the unstable substratum. Not only this, the anaerobic condition due to daily tidal condition, high salinity soil etc. also cause a high risk However, mangroves species have already developed some special features to overcome these problems and adapt the environment of mangrove. And I will present them in the following paragraph.

For those like Bruguiera gymnorrhiza and Kandelia candel, they also have ¡§knees¡¨ of the roots. These are formed periodically into ¡§knees¡¨ that project above the mud surface to facilitate gaseous exchange. Maybe talk more on Bruguiera gymnorrhiza, they have one special feature that is we call ¡§droppers¡¨. It is actually the germinated seeds that attached to the parent plants. These allow rapid growth and establishment of mangrove seedlings once they come contact with the substratum. As a result, the survival rate of the plants could be increased.

In this field trip, we have found and identified 32 different species of animals. From the graphs and tablets that we have constructed, we can found that there has two most abundant species: Clithon oualaniensis and Cerithidea rhizophorarum. Both of them have nearly 180 individuals and occupy nearly 30% of the relative density. From the graph, they usually located near the landward side of the mangrove (higher attitude, like above 20M). Besides it is quite obvious that the number of the animal species at the middle attitude of the mangrove (between 20-30M) is more than that at the extreme side. There should have some advantages to grow on there, e.g. the optimum salinity, the richness of nutrients etc. Similar to those I have mentioned in the plant analysis, this can be explained by the high risk for growing at too low attitude as the daily tidal condition cause many problems. For example, the Anaerobic condition due to flooding.

Some topics in this essay:
Analysis Brief, Tseng Tau, Introduction Mangrove, Mangrove Mangrove, Hong Kong, Deep Bay, kandelia candel, transect line, field trip, data collected, daily tidal, landward mangrove, plant species, tidal condition, daily tidal condition, near landward, adaptations live, near landward mangrove, adapt mangrove environment, grow near landward, anaerobic condition due,