Wave attenuation in mangrove forests; field data obtained in Trang, Thailand

Mangroves thrive in sheltered intertidal areas in the tropics and sub-tropics. Due to this position at the interface between land and sea, mangroves play an important role in the attenuation of waves. Dissipation of wave energy in mangrove forests is an interesting feature from the viewpoint of coastal protection. Nevertheless, field data are sparse and modeling attempts reveal the need for additional data. This paper presents the results of an extensive field campaign, lasting 6 months, in mangroves along the Andaman coast of Trang Province in southern Thailand. Wave attenuation has been studied along two contrasting transects with different elevation and vegetation characteristics and different orientations towards the Andaman Sea. Along the Kantang transect, which is mostly exposed to swell waves, vegetation densities increased from 4.5 to 9.3 volume-‰ along the transect and on average 63% of the incident wave energy was attenuated over a distance of 246 m. Along the Palian transect, mostly exposed to sea waves instead, vegetation increased from 4.3 to 19 volume-‰ and 72% of the incident wave energy was attenuated over this 98 m transect. It was found that standardized wave attenuation correlates well with incident wave energy, when attenuation is analyzed per vegetation zone. Energy reduction rates of these zones, defined by the gradient of the correlations between the standardized wave attenuation and incident wave energy, are found to increase significantly with vegetation density. Consistently, wave reduction rates, expressing the gradient of the correlation between wave height reduction and incident wave heights, are found to be 0.001-0.014 for the study sites and also show a significant and increasing trend with vegetation densities

ANALISA VEGETASI HUTAN MANGROVE TELUK GILIMANUK TAMAN \ud NASIONAL BALI BARAT

The objective of the research is to know the kinds of mangrove, the type which predominating, the important value indeks of mangrove vegetation and to know the pattern of zonasi Gilimanuk Bay of Taman Nasional Bali Barat. \ud The method of this research was done at the resort Gilimanuk Bay of Taman Nasional Bali Barat with large 325 Ha and that was done in july 2008. The method that was used in measurement and observation of mangrove vegetation that was use transek / single blok stripe. At measure partion \ud with measurement 20m x 20m for trees level, made smaller portion with measure 10m x 10m for trees pole level. While at portion with measure 5m x 5m collected wean level data and portion with measure 2m x 2m collected seedling level data. The result of this research showed that it was done in Gilimanuk Bay area that was gol 12 species of vegetation from 7 families from various check measure in 7 stripe. At Gilimanuk bay area, the species that predominating were S. alba, A. marina and C. tagal species. The vegetation \ud species tahat had high INP for the free value was S. alba species wih value 83,6%, for pillar level and stake level were C. tagal species with value 119,2% and 107,3%. \ud In general we can seen the pettern of zonasi mangrove Gilimanuk bay of Taman Nasional Bali Barat area the following were: zona close to sea that was S. alba and A. marina. The intermediate zona was R. mucronata, R. apiculata, R. stylosa species. The zona that near by land was C. tagal, B. cylindrical, B. mucronata, E. agallocha and O. octodanta. \ud According to this research, it was suggested that conducted by furthermore research about mangrove vegetation that exist in Taman Nasional Bali Barat area, conducting of mangrove along the coast, the social society economics around crackish territorial water organism composition area

A survey of selected coastal vegetation communities of Florida

A survey of coastal vegetation around Florida was conducted during 1973 and 1974. Seventeen sites were selected and sampled using the transect method to determine species occurrence, relative densities, and habitat development and structure. Sites were sampled quarterly except where high tides prevented data gathering. Species occurrence was compared within and between sites using Sarensen's Index of Similarity (IS,) as a basis for determining similarity of species inhabiting selected sites. Indices ranged from 4 to 61%, the former representing only one plant common to two sites. Results show environmental factors acting upon species alter species composition in seemingly similar habitats. Instead of the term "community", the term "association" is used to better reflect the concept of a taxonomically unrelated group of plants occupying a particular habitat. (Document has 40 pages.

STATUS OF MANGROVES IN SRI LANKA

In Sri Lanka many estuaries and lagoons are fringed with vastly diverse mangrove forests. The total mangrove cover is very small as 0.1 to 0.2 percent of the total land area. The distribution of fauna and flora varies along with wet and dry zone in the country. Around 25 species of flora are exclusive to mangroves and more than 25 species can be identified as associated mangroves. Variety of invertebrates and vertebrates are conspicuous in the mangrove forests, but only a few species are confined to the ecosystem. Heavy utilization and reforestation for shrimp farms and building construction work severely affect on this ecosystem. When compare to decline rate of mangrove forests in Sri Lanka, current implemented conservation measures are inadequate

Effect of Growing Season on Growth and Relation of Height and Above Ground Biomass of Avicennia Marina

Relation of height of seedling stands and above ground biomass is an important indicator of successful stand establishment and effectivity of carbon cycle which requires further study. This research aimed to study the growth level of Avicennia marina seedling planted in dry season and rainy season and to analyze the relation of mangrove stand height to above ground biomass of seedling for each season. This research was conducted through field experiment involving grouped random design including group of seedling plantation in dry season and rainy season with 40 replication for each group and 6 months of experiment period. Data collection including stand height above ground biomass, followed by data analysis on the relation of seedling height and above ground biomass. The result showed that the growth of mangrove stand planted in rainy season was better than those planted on dry season. Average height of mangrove Avicennia marina stand planted in dry season was 30,5 ± 7,3 cm while stand height of mangrove planted in rainy season was 42,7 ± 11,4 cm. Above ground biomass data showed the average of 4,1 ± 1,8 gr in the dry season treatment group and 6,6 ± 2,5 gr in the rainy season treatment group. Regression analysis on the relation of stand height and above ground biomass of Avicennia marina seedling showed that the above ground biomass was significantly affected by stand height both for dry season and rainy season treatments. But, there was a difference on the determination index and the coefficient of the effect on each treatment groups. The relation of stand height and above ground biomass was Y = 0.1871 X0.8832 with R2 = 0.2802 for the dry season group and Y = 0.0506 X1.2892 with R2 = 0.743 for the rainy season group.

Dissolved humic substances supplied as potential enhancers of Cu, Cd, and Pb adsorption by two different mangrove sediments

Purpose The external supply of humic substances has been recently suggested for the remediation of metal-polluted sediments; however, little is known about how to supply them and their effects on metal mobility. The study sought to investigate the sediment\u2014metals\u2014humic substance interaction in mangrove forest sediments. We aimed to evaluate the sediment adsorption potential in the case of large and rapid metal loads, as recently occurred in the Doce River (Brazil). Materials and methods In each mangrove forest sampling point of the Benevente River (RB) and Vitoria bay (MO), sediments were collected randomly along the river banks at a depth of 0\u201310 cm. Samples were characterized in terms of pH, CEC, organic carbon, texture, specific surface area, and elemental composition. The heavy metal content was measured by mass absorption spectrophotometry. Humic substances were extracted from the sediments according to the International Humic Substances Society (IHSS) method, avoiding separation of fulvic and humic acids. Original sediments were supplemented with humic substances and six Cu, Cd, or Pb concentrations. Freundlich and Langmuir equations were employed to create adsorption isotherms. Results and discussion The two sediments are significantly different, specifically with regard to organic carbon and Fe content, texture, and specific surface area. External humic substances increased the Cu adsorption capacity in both sediments but without an important change in Cu adsorption dynamics. Humic substances slightly increased the sediment adsorption capacity of Pb in RB sediment while they decreased in MO sediment, characterized by lower specific surface area, probably due to coverage of the active adsorption sites. Cd isotherms showed that the different characteristics of sediments alone do not affect Cd adsorption, but coupled with humic substances; Cd affinity for the soil surface increased five times in RB sediments confirming sediment-metal- humic substance interactions. Conclusions Humic substances affect soil metal retention mainly by altering the ion affinity for sediment surface, leading to contrasting results. The Fe concentration could be important depending on specific surface area and humic substance percentage, due to its capacity to form spheroids linked to molecules of humic substances on the clay surface. Several works have been carried out on this research area, but due to the many variables and different metal ions, we recommend further studies

A pedo-geomorphological classification and map of the Holocene sediments in the coastal plain of the three Guianas

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