Excoecaria agallocha

About: Excoecaria agallocha is a research topic. Over the lifetime, 362 publications have been published within this topic receiving 5042 citations. The topic is also known as: Gewa.

Biological Diversity Assessment of Tok Bali Mangrove Forest, Kelantan, Malaysia

Abstract: This paper attempts to give information about the structure of mangrove distribution at Tok Bali, Kelantan in order to initiate for management and rehabilitation program. A study was conducted in July to November 2006 to determine the species composition, diversity index and above-ground biomass in 15.8 ha Mixed Mangrove Forest. A transects forest profile length of 30 meter and 20 plots were established, a Diameter Breast Height (DBH) and height were measured and recorded, and also diversity index and above-ground biomass were determined. A total of 10 species consisting of nine exclusive and one non-exclusive mangrove were recorded. The common species found were Sonneratia alba (1,170 trees/ha, 330 saplings/ha and 22,680 seedlings/ha) followed by Ceriops decandra, Excoecaria agallocha, Avicennia alba, Bruguiera cylindrica, B. sexangula, Rhizophora apiculata, Aegiceras corniculatum, Nypa fruticans and Derris trifoliata. From the results an average of 595 trees/ha, 598 saplings/ha and 646 seedlings/ha represented a moderate good condition and regeneration potential. Total above-ground biomass was 2664.57 kg/ha and S. alba also recorded the highest because the of wide range of diameter and height. Mangrove trees showed total average of species richness (S) was 8.0, eveness (E) was 0.793 and diversity (H’) was 1.603.

Biodiversity and biomass of a natural and degraded mangrove forest of Peninsular Malaysia

Abstract: Anthropogenic activities have always been the cause of most environmental degradation, and mangrove disappearance is no exception. A comparative assessment on the biodiversity of natural and degraded mangrove forests has been undertaken, looking at the biomass, both above-ground and below-ground. The natural and the degraded mangrove forests were situated at Kuala Selangor and Sungai Haji Dorani, respectively, both on the West coast of Peninsular Malaysia. A random sample scheme with quadrate sample plots (10 m × 10 m) was adopted for the measurement of the diameter at breast height and total height of individual tree species at both forests. Diversity indices and above- and below-ground biomass were estimated from this inventory. Eight mangrove tree species were identified at both study areas, namely: Bruguiera parviflora, Avicennia officinalis, Rhizophora mucronata, Sonneratia alba, Avicennia marina, Bruguiera cylindrica, Xylocarpus mekongensis and Excoecaria agallocha. The mangrove species in Sungai Haji Dorani showed high diversity with a Shannon–Weiner Index (H′) value of 0.91, compared to the natural mangrove of Kuala Selangor which has a lower value, H′ = 0.55. The dominant species in the natural mangrove area was B. parviflora, with the highest Important Value Index (IVI) of 70.96 %, as opposed to A. marina which was the most common species in the degraded mangrove area, with IVI of 49.16 %. An estimate of 305.46 t/ha of above-ground biomass was calculated for the natural mangrove, while 122.78 t/ha was obtained for the degraded mangrove forest. This contrasts with the below-ground biomass estimates, which were 14.09 t/ha for the natural mangrove and 36.35 t/ha for the degraded mangrove.

Interference competition as a key determinant for spatial distribution of mangrove crabs.

Abstract: The spatial distribution of mangrove crabs has been commonly associated with tree zonation and abiotic factors such as ground temperature and soil granulometry. Conversely, no studies were designed to investigate the role of competition for resources and predation in shaping crab distribution in mangroves, despite these biotic factors are recognised as key determinants for spatial patterns observed in the communities colonising rocky and sandy intertidal habitats.We studied floral and faunal assemblages in two zones of a Sri Lankan mangrove, a man-made upper intertidal level and a natural eulittoral, mid-shore one. Leaf choice experiments were designed to study both feeding rate and intra and inter-specific interactions for food of sesarmid crabs in the two habitats in order to better understand crab spatial distribution. The two intertidal belts differed in terms of floral composition and crab species abundance. The eulittoral zone was strongly dominated by Neosarmatium smithi, while within the elevated littoral fringe four sesarmids (N. smithi, N. asiaticum, N. malabaricum and Muradium tetragonum) were more evenly distributed. At both levels, all sesarmids showed to collect significantly more Bruguiera spp. and Rhizophora apiculata leaves than Excoecaria agallocha ones. There was no temporal segregation in feeding activity among the four species, resulting in a high interference competition for leaves. Regardless of the habitat, N. smithi was always successful in winning inter-specific fights. Our results showed that the elevated littoral fringe was more crowded with crabs, but was less favourable in terms of food availability and environmental conditions. The dominance of N. smithi in gathering mangrove leaves suggests that this species may segregate the other sesarmids into less favourable habitats. The present data strongly suggest for the first time that interference competition for food can contribute to shape mangrove crab spatial distribution.