We review 72 published articles to elucidate characteristics of biomass allocation and productivity of mangrove forests and also introduce recent progress on the study of mangrove allometry to solve ...the site- and species-specific problems. This includes the testing of a common allometric equation, which may be applicable to mangroves worldwide. The biomass of mangrove forests varies with age, dominant species, and locality. In primary mangrove forests, the above-ground biomass tends to be relatively low near the sea and increases inland. On a global scale, mangrove forests in the tropics have much higher above-ground biomass than those in temperate areas. Mangroves often accumulate large amounts of biomass in their roots, and the above-ground biomass to below-ground biomass ratio of mangrove forests is significantly low compared to that of upland forests (ANCOVA,
P
<
0.01). Several studies have reported on the growth increment of biomass and litter production in mangrove forests. We introduce some recent studies using the so-called “summation method” and investigate the trends in net primary production (NPP). For crown heights below 10
m, the above-ground NPP of mangrove forests is significantly higher (ANOVA,
P
<
0.01) than in those of tropical upland forests. The above-ground litter production is generally high in mangrove forests. Moreover, in many mangrove forests, the rate of soil respiration is low, possibly because of anaerobic soil conditions. These trends in biomass allocation, NPP, and soil respiration will result in high net ecosystem production, making mangrove forests highly efficient carbon sinks in the tropics.
Mangrove species are uniquely adapted to tropical and subtropical coasts, and although relatively low in number of species, mangrove forests provide at least US $1.6 billion each year in ecosystem ...services and support coastal livelihoods worldwide. Globally, mangrove areas are declining rapidly as they are cleared for coastal development and aquaculture and logged for timber and fuel production. Little is known about the effects of mangrove area loss on individual mangrove species and local or regional populations. To address this gap, species-specific information on global distribution, population status, life history traits, and major threats were compiled for each of the 70 known species of mangroves. Each species' probability of extinction was assessed under the Categories and Criteria of the IUCN Red List of Threatened Species. Eleven of the 70 mangrove species (16%) are at elevated threat of extinction. Particular areas of geographical concern include the Atlantic and Pacific coasts of Central America, where as many as 40% of mangroves species present are threatened with extinction. Across the globe, mangrove species found primarily in the high intertidal and upstream estuarine zones, which often have specific freshwater requirements and patchy distributions, are the most threatened because they are often the first cleared for development of aquaculture and agriculture. The loss of mangrove species will have devastating economic and environmental consequences for coastal communities, especially in those areas with low mangrove diversity and high mangrove area or species loss. Several species at high risk of extinction may disappear well before the next decade if existing protective measures are not enforced.
This paper outlines the process of: assembling an empirical data set relating to the values of resource ‘goods and services11The term ‘goods and services’ is used in this paper to encompass all the ...elements normally evaluated as part of the process of determining total economic value.’ derived from coastal habitats bordering the South China Sea; standardising these data as production values per hectare per annum; converting local currencies to US dollars; and converting these values to a standard year (2007) by means of the consumer price index. In order to address the problem of the wide variation in prices within one country, the data were weighted to determine a ‘Weighted Mean National Value’ that reflected both the prices for the same resource at each location and the ‘stock’ of that resource at the same locations. This results in a national value that reflects the totality of the national stock rather than being a simple arithmetic average of all values. The determination of weighted mean regional values was undertaken in a similar manner to the computation of weighted mean national values but using data and information concerning the total stock (or area) in each country and the weighted mean national values. These weighted regional mean values were subsequently used in a cost benefit analysis of actions to conserve regional coastal habitats.
What has resulted from this work is a standardised method for calculating national and regional weighted mean values of resource ‘goods and services’ that can be applied more widely in handling and manipulating economic valuation data from multiple locations across any time span. The method can be applied in any region where multiple currencies, varying exchange rates and widespread inter-location variations in farm gate prices are found. The specific targets of the revised Strategic Action Plan for the South China Sea have been valued or, more specifically, the incremental benefit derived from achieving the SAP target has been valued. The values saved by achieving the targets are then compared with the costs of implementing the actions defined in the regional SAP through a cost benefit analysis.
•The total economic value (TEV) of mangrove bordering the South China Sea is presented.•Regional TEV is derived from weighted mean national TEVs for seven countries.•Incremental benefit derived from achieving the action plan targets has been valued.•Costs as a percentage of benefits of actions in the action plan are found to be 0.2%.
We report the results of a study of the physical characteristics and socio-economic impacts of the Indian Ocean Tsunami of 26 December 2004 on the tourist island of Langkawi, Malaysia. In comparison ...with many other locations struck by the tsunami, the immediate physical and socio-economic impacts in Langkawi were relatively minor. A detailed survey of the watermark and ground elevations was undertaken in the worst affected area between Sungei Kuala Teriang and Sungei Kuala Melaka. Here, the tsunami reached a maximum elevation of 4.29 m as it crossed the coast, with a maximum flow depth of 2.0 m and a very consistent run-up elevation relative to mean sea level of 300 ± 10 cm. The tsunami inundated inshore areas for 300 m and penetrated inland along creeks for 500-1000 m. Structural damage to buildings was confined to within 50-150 m of the shoreline where about 10% of the houses were completely destroyed and 60-70% suffered significant structural damage. Damage was particularly severe in areas where there was no engineered coastal protection, but while coastal revetments did provide enhanced protection for houses at the waterfront, the coastline in the study area appeared to be more heavily impacted than elsewhere in Langkawi because wave energy was focused on the area by offshore breakwaters built to protect the Langkawi port and airport. Emergency response after the tsunami was rapid and efficient but would have been improved if the local police station had not been rendered inoperative by the first wave, and if a mechanism had been in place to ensure that informal advance warnings transmitted between Phuket (Thailand), Langkawi and Penang (Malaysia) by tourist operators could have been more widely disseminated.
The ecology of mangrove conservation and management Eong, O.J. (Universiti Sains Malaysia, Penang (Malaysia). Centre for Marine and Coastal Studies)
Hydrobiologia,
01/1995, Letnik:
295, Številka:
1-3
Journal Article
Stratigraphy, grain size distribution and foraminiferal assemblages of pre-tsunami and tsunami sediment from the Indian Ocean Tsunami at five sites along the Malaysia–Thailand Peninsula were analyzed ...to gain information on tsunami sediment source and deposition style. Between three and five stratigraphic units were identified at each site and contained between one and three fining upward sequences reflecting waning flow or pre-backwash deposition. Coarser sand layers reflecting uprush high-energy flow separated the fining upward sequences, with the exception of one site (Sungai Burong), which contained a coarsening upward sequence. All contacts between the pre-tsunami and tsunami sediment were sharp or erosional. Medium and coarse sand dominated all of the tsunami sediment deposits and often contained shell fragments. Foraminiferal assemblages were able to differentiate pre-tsunami sediment from tsunami sediment where no lithological or grain size distribution change was evident. Between two and four foraminiferal zones were identified at each of the five sites and provided estimates of sediment source and wave characteristics.
The use of demographic studies in mangrove silviculture Khoon, G.W. (Universiti Sains Malaysia, Penang (Malaysia). School of Biological Sciences); Eong, O.J
Hydrobiologia,
01/1995, Letnik:
295, Številka:
1-3
Journal Article
The goods and services that mangrove forests provide to society are widely understood but may be too generally stated to serve as useful guidelines in decision-making. Understanding the differences ...between fringe, riverine, and basin forests may help to focus these guidelines and to determine the best use of a particular forest. Fringe mangroves are important primarily for shoreline protection. Riverine forests, which are likely to be the most productive of the three types of forests, are particularly important to animal and plant productivity, perhaps because of high nutrient concentrations associated with sediment trapping. Basin forests serve as nutrient sinks for both natural and anthropogenically enhanced ecosystem processes and are often important sources of wood products. Exploitation of a forest for one particular reason may make it incapable of providing other goods and services.
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