The Majestic Mangroves

The Pran Buri River

      The combination of salt water that flows in from the sea and fresh water from the river has fostered a Mangrove ecosystem along the PranBuri River. The Pran Buri Mangrove Reserve protects this Mangrove ecosystem from being cleared away for agricultural and industrial purposes. Last month, I got a chance to visit the Mangrove Reserve, and to study the unique and distinctive characteristics of the Mangroves and the communities that have grown around the forest park.

     The terrestrial plants that grow along the Pran Buri river have to adapt to the tidal nature of the area and the extreme saline conditions of the river. Mangroves have adaptations that allow for them thrive in such a condition. While at the reserve, I saw that the Red Mangroves had spidery roots that protruded out the muddy soil. They have such characteristics because the roots provide a structural support in the soft soils for the plants to grow. These above ground roots are filled with spongy tissues and small holes that allow oxygen to be transfered to the roots trapped below ground, where oxygen is scarce. The leaves on the mangrove trees have adaptations that are suitable for the saline conditions of the water. Mangroves, particularly the Grey mangroves near the cost of the river have leaves with glands that secrete salt. Their leaves can also tolerate the storage of large amounts of salts.     In this ecology field study, the biotic and abiotic factors of the Red and Grey Mangrove communities were measured. Although these two communities of mangroves were relatively close to one another, they have so sufficiently adapted to their environments that each species of Mangrove have developed distinctive characteristics. To collect data for the biotic factors in the Grey Mangroves, a continuos belt transect was laid out along the ground, from the edge of the river to the edge of the forest. The organisms along the transect were then counted, and the abiotic factors such as temperature, water quality, light intensity, and turbidity were measured. The data collected for this community of mangrove is shown in the table below.
Biotic Factors of the Grey Mangrove Community 

Species	Number of Organisms
Big mangroves (mature)	19
Intermediate mangroves	10
Seedlings	55
Moss	53
Red Ants	A lot > 200
Small black ants	A lot >200
Spiders	2
Total	> 539

The biotic characteristics of the Grey Mangroves and the Red Mangroves community were rather different.The continuous belt transect could not be used to collect data for the biotic factors in the Red Mangrove  because of the mangroves' protruding roots. Instead the quadrant sampling method was used. The biotic data collected for this community is shown in the table below. 

Biotic Factors of the Red Mangrove Community 

Species

Number of Organisms

Merder’s Mangrove crabs	4
Spiders	1
Total	5

With every ecology field study comes uncertainty in the data that was collected. Some systematic errors in the sampling method of each mangroves were that the area and transect that were chosen for sampling were not randomly selected. The average number of each species in the sampling area could not be taken either because only one transect and a quadrat were used to sample the area. 

I wanted to compare the relative biodiversity of each of the mangrove community using Simpson's Diversity Index. When calculated, the biodiversity of the Grey Mangroves was 0.297 and the Red Mangroves' was 0.60. Although there were fewer number of organisms and species in the quadrat of the Red Mangroves, because the population of the organisms in the Grey Mangroves is largely concentrated on the ant population, the area of the Red Mangroves is considered to be more diverse. A bar graph comparing the relative biodiversity for each of the mangrove community is shown below. 

From just merely observation alone, I could see that the mangrove ecosystem has unique adaptions that allows for them to thrive in an area where other terrestrial plants cannot. The mangroves and other small animals have found its own unique way to adapt to the environment that they were living in. None of the crabs that lived in the Red Mangrove community could be found where the Grey Mangroves grew because of the difference in quality of soil between the two community. Instead small periwinkles and snails were found along the trunks of the Grey Mangroves where the soil was less moist and condensed.

       Because the Grey Mangrove community was located right at the mouth of the river, the plants and small animals there have adaptations that are different from the organisms that live in the Red Mangroves. But in either community, the organisms have adaptations that are so well suited to the particular environment that their population is able to thrive.