One of the most important problems in the coastal areas all over the world is erosion which has threatened human activities in the areas exposed to such hazard. Coastline retreat could result in very serious economic, environmental, and social impacts depending on the eroded area.
Mangroves are complex ecosystems that provide coastal bioshield to save guard coastal habitats and societies from natural disasters. Following the Indian Ocean tsunami of 26 December 2004 it was reported that mangroves and coastal forests are
Wave energy and storm surges threaten coastal ecology and nearshore infrastructures. Although coastal structures are conventionally constructed to dampen the wave energy, they introduce tremendous damage to the ecology of the coast. To minimize environmental impact, ecofriendly coastal protection schemes should be introduced. In this paper, we discuss an example of an innovative mangrove rehabilitation attempt to restore the endangered mangroves on Carey Island, Malaysia. A submerged detached breakwater system was constructed to dampen the energy of wave and trap the sediments behind the structure. Further, a large number of mangrove seedlings were planted using different techniques. Further, we assess the possibility of success for a future mangrove rehabilitation project at the site in the context of sedimentology, bathymetry, and hydrogeochemistry. The assessment showed an increase in the amount of silt and clay, and the seabed was noticeably elevated. The nutrient concentration, the pH value, and the salinity index demonstrate that the site is conducive in establishing mangrove seedlings. As a result, we conclude that the site is now ready for attempts to rehabilitate the lost mangrove forest.
At a regional scale, the high species numbers (gamma diversity) of tropical forests have been explained by either a gradual accumulation of species through time (museum hypothesis) or, by contrast, rapid recent speciation in large genera. However, the origins of local rain forest diversity (alpha diversity) have been given little attention. Cyrtandra (Gesneriaceae), an understorey genus in the highly species-rich Indo-Malayan rain forest, has considerable capacity for producing local endemics, making it particularly suitable for studying diversity on a local scale. We sampled Cyrtandra species from one community on Mount Kerinci, Sumatra, and phylogenetic analyses of ITS sequences suggest that this community is an assembly of three distinct phyletic lineages: (1) a group of herbaceous or subshrub plants of Bornean affinity, (2) one member of a group of widespread shrubs forming Cyrtandra section Dissimiles and (3) a second group of shrubs. The evolutionary origin of this community is therefore not a result of rapid and recent speciation: it is assembled from species resulting from a gradual accumulation of diversity through time (museum hypothesis), although one lineage shows evidence of more recent, continuing speciation than the other two. The community includes two distantly related, apparently endemic species, but there is no evidence for a local adaptive radiation. The protection of representative species from each lineage would allow the conservation of genetic diversity.
Species composition, diversity and richness of pteridophytes were observed in three oil palm plantations of different age and management histories at Segamat, Johor using random sampling method. A total of 3762 individuals of pteridophytes consisting of 32 species belonging to 13 families from 20 genera were identified and recorded. Family Polypodiaceae, genera Microsorum and family Davalliaceae, genera Davallia contributed to the highest richness of species and were commonly found within the study area. The diversity index represented by Shannon Index, H’, is 2.51 whereas the computed evenness index is 0.72 for the overall pteridophytes species indicating a relatively high species distribution within the monoculture system. The species richness in Kg. Sri Rahmat oil palm plantation was found higher than Kg. Logah and Felda Medoi oil palm plantation with 2.15, 2.10 and 2.09 respectively. From the total recorded species of pteridophytes, the highest diversity is observed at the Kg. Sri Rahmat (H’=2.07) followed by Kg. Logah (H’=1.81) and Felda Medoi (H’=1.79). At Kg. Sri Rahmat, the species evenness is nearly even (EH=0.73) whereas at Kg. Logah and Felda Medoi, the species evenness was less significant different (EH=0.66 and EH=0.65). The type of fertilizer used, frequency of herbicide application and pruning activity at Kg. Sri Rahmat could potentially affect the diversity of pteridophytes species in the plantation. This highlights the potential of oil palm plantations owned by smallholders as an ecosystem support for the diversity of pteridophytes species. However, this may vary with different plantation age and management history.
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