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... cover approximately 350 ha (Pahalawattaarachchi and Amarasinghe 1995) and the largest extent occurs in the northern part of the estuary that opens up to the Indian Ocean. Kadolkele is situated on the northeastern shore of the estuary and covers approximately 15 ha of the inter-tidal zone (Figure 1). ...
Context 2
... cover approximately 350 ha (Pahalawattaarachchi and Amarasinghe 1995) and the largest extent occurs in the northern part of the estuary that opens up to the Indian Ocean. Kadolkele is situated on the northeastern shore of the estuary and covers approximately 15 ha of the inter-tidal zone (Figure 1). ...
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Citations
... Observations lead to the belief that mangroves and other coastal forests are of great service to the coastal communities as protectors of the coast by dissipating the energy of waves and checking erosion, dampening winds and storms, and also reducing tidal/ saltwater intrusion to the hinterland (Amarasinghe, 1997a(Amarasinghe, , 1988Jayakody et al., 2008;Zhang et al., 2012;Krauss and Osland, 2020). The capacity of mangrove ecosystems to resist tidal currents and waves depends on its vegetation characteristics such as density, height, species composition, width of the forest, diameter of mangrove roots and stems, as well as the topography of mangrove habitats, that create drag force, resulting attenuation of energy in waves, preventing coastal erosion (Menashe, 1993;Barbier, 2006;De Silva, 2011;Zhang et al., 2012). ...
... Mumby et al. (2004) revealed that some fish species such as Scarus guacamaia, which is the largest herbivore species in the Atlantic suffered extinction due to the degradation of mangrove habitats, suggesting that the survival of some fishes strongly depend on mangrove habitats. Mangroves are a highly productive ecosystem and their productivity is not proportional to the global coverage of mangroves (Amarasinghe and Balasubramaniam, 1992;Jayakody et al., 2008). Mangroves have been estimated to produce 11% of marine organic matter (Faunce and Serafy, 2006) which may contribute to marine food webs (Amarasinghe, 1997b;Hutchison et al., 2014) and hence to fish production. ...
Mainstreaming coastal biodiversity certainly brings nature-based solutions for the conservation of offshore and onshore resources. Being an island, the long-term shoreline change of Sri Lanka is particularly important for management of the island's coastal resources. This study was carried out at the southwestern and southern coasts of Sri Lanka to investigate the protective capacity of mangroves against coastal erosion, and coastal inundation hazards due to the climate associated sea-level rise. Structural diversity of mangrove stands was assessed in terms of alpha-diversity, plant species richness, basal area, tree height, density, and structural complexity index. Analysis of aerial photographs and the ASTER Global Digital Elevation Model was used to identify shoreline changes along the southwestern and the southern coasts of Sri Lanka. Results revealed that by and large, the southwestern coast is highly vulnerable to coastal erosion and inundation hazards whereas the southern coast manifests a tendency to retreat. The average annual rate of shoreline change however varies within the two coastal areas, as there were accreting as well as eroding segments on both southern and southwestern coasts, nevertheless, all retreating beach segments were the sites of improper maritime developments. Segments with lower rates of shoreline erosion and coastal inundation hazards were found to be located close to the mangrove and other coastal vegetation with varying structural complexity and diversity. Reforestation and restoration of vegetation in coastal lagoons and estuarine habitats are evidently effective strategies not only to protect the low-lying coastal hinterlands but also to preserve coastal biodiversity. (
... Several studies have reported that Avicennia marina is largely predominant in high saline environments, where salinity is shown to be ≥ 25 ppt during most of the months of the year [36,37]. Moreover, Avicennia marina is a facultative halophyte having various adaptations for hyper saline environments [38,39], urban runoff and fishing yield to an aggravated problem. Guhathakurta and Kaviraj [40] demonstrated similar deductions. ...
... Rate of photosynthesis vary widely among the physical environmental factors as well as vegetation structural characteristics. Complexity index (CI) represents the vegetation structure of the mangrove stand, that contributes to functions of the mangrove ecosystem, revealed a strong positive relationship with the GPP calculated for Negombo estuary and similar relationships were reported by Jayakody et al. (2008) and Perera et al. (2010) for mangrove areas in Negombo estuary. Woodroffe (1993) explain geomorphology and hydrology determined by local geology, sea-level change, tide, fresh water input, shoreline structure, watershed morphology, groundwater influence, natural disturbance regimes and climate, contribute to development of physio-chemical gradients which in turn govern the structure and function of the intertidal ecosystems. ...
... Distribution of plant communities along climatic and topographic gradients were determined based on species richness, stand density, Shannon index of diversity, basal area, and Simpson index of dominance (Josph et al., 2008).Species richness showed a unimodal distribution with respect to elevation gradient, low (<800 m) and high (>1000) elevation zones had lower species richness, while medium elevation zones (800-1000 m) showed higher species richness and diversity (Josph et al., 2008). Variation structure was determined by species diversity and relative densities of constituent species at SriLanka (Jayakody et al., 2008). Variation in quantitative parameters like, species richness and species diversity is related to variations in edaphic factors, elevation, slope aspect and micro-climatic conditions between the two sites (Shameem and Kangroo, 2011). ...
Asphodeline lutea plant species is an edible plant with sweet taste used by local communities as a medicinal plant and it can be taken fresh or roast. The diversity of Asphodeline lutea plant species was studied at AlShoubak and AlNaqab regions of Ma'an governorate Southern part of Jordan. Quadrat-transect method was randomly used to determine the density, richness, dominance and evenness indices under selected sites. A total of 90 quadrats of 0.5mx0.5m size were laid down at 50m intervals along parallel line transects. A total of 15 vegetation species were recorded during this study. Of the 15 species, the most popular medicinal plants used in folk medicine (Paronychia argentea and Teucrium polium) were not recorded in all sites. Shannon diversity value was higher at AlJhair site with elevation 1548m. Among studied sites West direction showed high species richness (9) while the South direction recorded the lowest species richness (4) at AlNaqab/AlHiyad site with elevation 1554m. Among studied sites high density and frequency values of Asphodeline lutea species were recorded to AlShoubak castle and AlNaqab/AlHiyad, 5.33 and 0.93, respectively. Cyndon dactylon species has the highest density values (10.8 and 5.8). Approximately at all studied site Artemisia herba-alba Asso. considered the dominant plant and an associated for most vegetation species. Management plan for conserving the plant genetic resources at their natural habitats is necessary for next and present generations.
... dominated in between the above 2 zones. A study by Jayakody et al. [32] has also shown a similar mangrove zonation in Kadolkele mangrove forest. Kadolkele mangrove forest. ...
... The soil moisture content, organic matter content conductivity, salinity, and penetrability are high in the middle Avicennia zone (see also Table 9 for further details). In spite of the understanding of ecological, economic, and social importance of the Kadolkele mangrove forest [32][33][34][35][36] little is known about the ecology of its macrobenthic fauna. Therefore the present study was designed focusing on some aspects of the ecology of these macrobenthic fauna and showed that they exhibited a distinct variation in parallel to the variation of physicochemical parameters of soil between the 3 mangrove zones there. ...
The ecology of the macrobenthic fauna of the mangrove forests has received little attention compared to the mangrove flora. The present study was aimed at filling this information gap and investigated if the diversity and distribution of macrobenthic fauna at Kadolkele mangrove forest, a pristine mangrove forest situated at the Negombo estuary in Sri Lanka, are governed by the mangrove zonation and variation of physicochemical parameters of the mangrove soil. Since the aerial photographs identified three distinct mangrove zones at Kadolkele, namely, Rhizophora, Avicennia, and Lumnitzera zones, fauna were sampled and physicochemical parameters of the soil were measured in belt transects that were established at each mangrove zone. Data were collected and analyzed using appropriate field sampling techniques and statistical methods, respectively. Results revealed that the physicochemical parameters in soil varied between the three mangrove zones and that the distribution of benthic fauna followed the mangrove zonation. Further, the diversity measures of epifauna were found to be higher than those of the infauna of this tropical estuary.
... Several studies have reported that Avicennia marina is largely predominant in high saline environments where salinity is ≥ 25 ppt during most months of the year (Karunathilake 2003; Jayatissa et al. 2008). However, in the present study Avicennia marina cover along with other mangrove species is relatively high at the locations P2-P4 (i.e., the Sathurukkondan area) compared with the pristine location P1 at Palameenmadu (species abundance not shown) indicating that Avicennia marina is a facultative halophyte having various adaptations for hypersaline environments (Shete et al. 2007;Jayakody et al. 2008). ...
Batticaloa Lagoon (Sri Lanka) is subjected to significant pollution as a result of anticipated unplanned development works since the cessation of a civil war in May, 2009. This paper presents the effectiveness of Avicennia marina (Forsk.) Vierh in the phytoremediation of Pb and the variation of Pb in sediments and water in the intertidal zone under drier weather conditions. Four pristine areas and 4 mangroves cut areas within the Manmunai North Divisional Secretariat Division/Batticaloa Municipal Council areas were investigated. Pb levels in the sediments and plants were negligible at all locations (i.e., below the method detection limit of the AAS for sediments and plants which is 0.25 mg/kg dry weight and 0.5 mg/kg dry weight, respectively). However, the water environment showed significant contamination (0.17-0.29 mg/L and 0.26-0.34 mg/L in pristine areas and cleared areas, respectively), hence Pb bioaccumulation is likely in fish and other biota. Avicennia marina is not effective to phytoremediate Pb under significant saline conditions.
... dominated in between the above 2 zones. A study by Jayakody et al. [32] has also shown a similar mangrove zonation in Kadolkele mangrove forest. Kadolkele mangrove forest. ...
... The soil moisture content, organic matter content conductivity, salinity, and penetrability are high in the middle Avicennia zone (see also Table 9 for further details). In spite of the understanding of ecological, economic, and social importance of the Kadolkele mangrove forest [32][33][34][35][36] little is known about the ecology of its macrobenthic fauna. Therefore the present study was designed focusing on some aspects of the ecology of these macrobenthic fauna and showed that they exhibited a distinct variation in parallel to the variation of physicochemical parameters of soil between the 3 mangrove zones there. ...
Mangrove forests are highly productive ecosystems that are associated with tropical estuaries in the world. The ecology of the soil dwelling macrobenthic fauna of these mangrove forests have received little attention compared to the above ground mangrove flora. Therefore a study was carried out starting form June-July 2013 at the Kadolkele mangrove forest, a pristine mangrove forest patch situated at the Northern extremity of the Negombo estuary in Sri Lanka to investigate if the diversity and distribution of mangrove associated macrobenthic fauna, both infauna and epifauna, are governed by the mangrove zonation and by the variation of physico-chemical parameters in the mangrove soil.
Three distinct mangrove zones were identified in this mangrove forest. The narrow Rhizophora zone occurred bordering the estuary and the wider Lumnitzera zone occurred at the deeper landward side, while the Avicennia zone occurred in between the above two mangrove zones. Three belt transects, each with a length and width of 40 m and 3 m respectively, were established in the middle of each mangrove zone. Along each transect, 12 quadrat sampling areas of 2 m × 2 m were established with a gap of 2 m in between. The number of mature mangrove trees, seedlings up to 1 m in height and their pencil roots within each quadrat were counted and recorded separately. The infauna and epifauna within these quadrats were sampled and identified. The total abundance, species richness, species heterogeneity and species evenness of the infauna and epifauna were determined separately. The physico-chemical parameters in soil i.e. pH, conductivity, salinity, moisture content, organic matter content, sand %, silt % clay %, penetrability, and depth of the redox layer were measured and analyzed using standard techniques and the variation of the above biotic and abiotic data were analyzed parametrically and non-parametrically using appropriate statistical methods.
Results showed that the physico-chemical parameters in soil varied between the 3 mangrove zones and that each mangrove zone was characterized by some physico-chemical variables. The epifaunal diversity i.e. total abundance, species richness, species heterogeneity and species evenness, were higher than the infaunal diversity. Molluscs and crustaceans dominated the epifaunal community while the oligochaete worm Limnodrilus sp. dominated the infaunal community.
The fauna also showed a distinct zonal variation between the 3 mangrove zones. For example, Limnodrillus sp. and the epifaunal crustacean Sesarma guttatum were characteristic to the upper Lumnitzera zone while Limnodrillus sp. again and an epifaunal mollusc Cassidula nucleus (Nucleus Cassidula snail) were characteristic to the lower Rhizophora zone. Although there were no infauna recorded in the middle Avicennia zone, there were many epifaunal species in this zone and was characterized by Sesarma smithii and Paratrechina longicornis (Black Ant).
The total abundance, species richness, species heterogeneity and species evenness of the infauna increased with the depth of the redox layer, clay %, sand %, silt % and pH. Therefore it is apparent, that the diversity and the distribution of the macrobenthic fauna in the Kadolkele mangrove forest is determined by the physico-chemical parameters of soil and the zonation of mangroves there.
... Because the intertidal swath is narrower in Sri Lanka than in other parts of the Indo-Malay Region, on account of the small tidal amplitude, mangroves show a ribbon or patchy development instead of occurring in extensive swampy forests (Swan 1983). Distribution patterns of mangroves and their diversity in Sri Lanka are fairly understood (Aruchelvam 1968;De Silva 1986;Pinto 1986;Jayasuriya 1991b;Amarasinghe and Balasubramaniam 1992a, b;Amarasinghe 1997a, b;Pinto and Swarnamali 1997;Jayewardena et al. 1999;Jayatissa et al. 2002a, b;Dahdouh-Guebas et al. 2005;Jayakody et al. 2008;NECCDEP 2010c). ...
... dominated in between the above 2 zones. A study by Jayakody et al. [32] has also shown a similar mangrove zonation in Kadolkele mangrove forest. Kadolkele mangrove forest. ...
... The soil moisture content, organic matter content conductivity, salinity, and penetrability are high in the middle Avicennia zone (see also Table 9 for further details). In spite of the understanding of ecological, economic, and social importance of the Kadolkele mangrove forest [32][33][34][35][36] little is known about the ecology of its macrobenthic fauna. Therefore the present study was designed focusing on some aspects of the ecology of these macrobenthic fauna and showed that they exhibited a distinct variation in parallel to the variation of physicochemical parameters of soil between the 3 mangrove zones there. ...
Analysis of physico-chemical parameters gives an insight to the the spatial distribution of benthic communities in estuaries. With this view the present study was carried out to see whether the spatial distribution of macrobenthic fauna is governed by the physico-chemical parameters in sediment and overlying water in Negombo estuary, Sri Lanka. This study also attempted to determine the key physico-chemical determinants that govern this spatial distribution.
During the study, the macrobenthic fauna at Moya, Virisiyanu Duwa, Kadol Kele, Dungalpitya, and Pamunugama within the estuary were collected and their species diversity and species richness were determined. Physico-chemical parameters such as the pore water salinity, temperature, pH, sand %, silt %, clay % and OM % in sediment as well as the salinity, pH, temperature, conductivity, DO, BOD5 and NO3- concentration in the over lying water were measured and analyzed using appropriate standard techniques.
Results revealed that the species richness, species diversity, structure of the macrobenthic community and the physico-chemical parameters in sediment and the over lying water and the varied significantly between the five study sites. However, the species diversity and the species richness were positively correlated with the salinity and sand % while they were negatively correlated with the BOD5, silt % and OM % in the sediment and overlying water. It is therefore evident that the spatial distribution of macrobenthic fauna in Negombo estuary is governed by a combination of some key physico-chemical parameters such as salinity, sand %, OM % and BOD5 in the sediment and over lying water in this tropical estuary.
... dominated in between the above 2 zones. A study by Jayakody et al. [32] has also shown a similar mangrove zonation in Kadolkele mangrove forest. Kadolkele mangrove forest. ...
... The soil moisture content, organic matter content conductivity, salinity, and penetrability are high in the middle Avicennia zone (see also Table 9 for further details). In spite of the understanding of ecological, economic, and social importance of the Kadolkele mangrove forest [32][33][34][35][36] little is known about the ecology of its macrobenthic fauna. Therefore the present study was designed focusing on some aspects of the ecology of these macrobenthic fauna and showed that they exhibited a distinct variation in parallel to the variation of physicochemical parameters of soil between the 3 mangrove zones there. ...
Analysis of physico-chemical parameters gives an insight to the the spatial distribution of benthic communities in estuaries. With this view the present study was carried out to see whether the spatial distribution of macrobenthic fauna is governed by the physico-chemical parameters in sediment and overlying water in Negombo estuary, Sri Lanka. This study also attempted to determine the key physico-chemical determinants that govern this spatial distribution.
During the study, the macrobenthic fauna at Moya, Virisiyanu Duwa, Kadol Kele, Dungalpitya, and Pamunugama within the estuary were collected and their species diversity and species richness were determined. Physico-chemical parameters such as the pore water salinity, temperature, pH, sand %, silt %, clay % and OM % in sediment as well as the salinity, pH, temperature, conductivity, DO, BOD5 and NO3- concentration in the over lying water were measured and analyzed using appropriate standard techniques.
Results revealed that the species richness, species diversity, structure of the macrobenthic community and the physico-chemical parameters in sediment and the over lying water and the varied significantly between the five study sites. However, the species diversity and the species richness were positively correlated with the salinity and sand % while they were negatively correlated with the BOD5, silt % and OM % in the sediment and overlying water. It is therefore evident that the spatial distribution of macrobenthic fauna in Negombo estuary is governed by a combination of some key physico-chemical parameters such as salinity, sand %, OM % and BOD5 in the sediment and over lying water in this tropical estuary.
Key words: Negombo estuary, Physico-chemical parameters, Spatial variation of Macrobenthic communities.
