Browsing by Author "Bellanthudawa, B.K.A."

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Abundance-Biomass Comparison approach to assess the environmental stressors in Diyawannawa wetland in monsoonal and non-monsoonal seasons
(Sri Lanka J. Aquat. Sci, 2018) Wijeyaratne, W.M.D.N.; Bellanthudawa, B.K.A.
Abundance-Biomass Comparison (ABC) approach is a graphical approach that compares the abundance and biomass of organisms in order to predict the environmental stress level of an ecosystem. The present study was conducted in selected sites located at non-rehabilitated and rehabilitated areas of the Diyawannawa wetland in Sri Lanka in the monsoonal and non-monsoonal seasons. The ABC was performed on the macrobenthic mollusk species collected from the study sites. Eight species of macrobenthic mollusks, namely, Bithynia tentaculata, Melanoides turbeculata, Melanoides turriculus, Thiara scabra, Lamellidens marginalis, Pila globosa, Gyraulus saigonensis and Lymnaea stagnalis were recorded during the study period. Based on Principal Component Analysis, B. tentaculata, and, P. globosa were identified as characteristic gastropod species that could be used to classify study sites in the rehabilitated and non-rehabilitated areas of this tropical wetland system. In the monsoonal season, overlapping cumulative percentage dominance of abundance and cumulative percentage dominance of biomass curves in sites A, B, and F indicated partially disturbed environmental conditions. The site C of the non-rehabilitated area, showed a typical undisturbed condition and the sites D and E of the rehabilitated area the cumulative percentage dominance of biomass curve was located above the abundance curve, indicating disturbed environmental conditions in these sites during monsoonal season. During the non-monsoonal season in all the sites except site F of the rehabilitated area, the cumulative percentage dominance of abundance curve was located above the biomass curve, indicating undisturbed environmental conditions in these sites. In the site F, the cumulative percentage dominance of abundance and the cumulative percentage dominance of biomass curves were crossing each other, indicating partially disturbed environmental conditions at this site. The values of the W statistic, which ranged from 0.004 to 0.374 in the non-monsoonal season and ranged from 0.1 to 0.2 in the monsoonal season, and pollution and water quality categorization by modified biotic index (MBI) were in agreement with the results of the ABC approach.
Assessing the environmental stress in the Diyawannawa wetland using macro-benthic molluscan diversity based Abundance-Biomass Curves
(Sri Lanka Association for the Advancement of Science Proceedings of the 73rd Annual Sessions, 2018) Bellanthudawa, B.K.A.; Wijeyaratne, W.M.D.N.
The present study assessed the variation of macrobenthic molluscan abundance and biomass with spatial variation of water and shallow sediment quality parameters in the rehabilitated and nonrehabilitated regions of the Diyawannawa wetland. Six sampling sites, reflecting various land uses in the non-rehabilitated (Site A,B,C) and rehabilitated (Site D,E,F) areas of the Diyawannwa wetland, were selected. At each site, DO, nitrate concentration, total phosphate (TP) concentration, BOD5, COD, chlorophyll-a (Chl-a) concentration of water, sediment conductivity, sediment pH, sediment percentage organic matter (%OM), sand%, silt%, clay%, and abundance and biomass of macrobenthic molluscs were recorded. Sampling was done from April to October 2016. One way ANOVA followed by Tukey’s pairwise comparison was used to assess the spatial variation of water and sediment quality parameters. The correlation between macrobenthic mollusc abundance and water and sediment quality parameters were determined by Pearson’s correlation analysis. Abundance- Biomass Comparison (ABC) Curves of molluscs were plotted. The significantly high mean abundance of Bithynia tentaculata (35), Melanoides turbeculata (5), Lamellidens marginalis (3) and Pila globosa(2) were recorded in site F, of the rehabilitated area where there was a significant input of solid waste, runoff sediments and organic matter. A significant spatial variation of nitrate N, COD, BOD5, Chl-a, DO, % sand, % OM, sediment pH, and conductivity was recorded in rehabilitated sites. Significantly high mean nitrate, Chl - a, COD, and % OM were recorded in site F. Bithynia tentaculata and Pila globosa showed a significant positive correlation with shallow water Chl - a, nitrate content, TP, COD and BOD5;Bithynia tentaculata was the biomass dominant species in all sampling sites. The highest and lowest percentage of biomass of Bithynia tentaculata was recorded in Site F (78.13 %) and in Site B (41.40%) respectively. The ABC curves indicated Site A as a typical unstressed site while Site F as a heavily stressed site. All the other sampling sites were moderately stressed and the level of disturbance varied among the sites. Further based on water and sediment quality data, it can be concluded that most of polluted sites (Sites E and F) are in moderate to heavily stressed condition, while comparatively less polluted sites (Sites A to D) are in unstressed to moderate stressed condition.
Identification of Macrophyte Indicator Species to Evaluate the Water Quality in Wetland
(Proceedings of the 22nd International Forestry and Environment Symposium 2017, 2017) Bellanthudawa, B.K.A.; Wijeyaratne, W.M.D.N.
Present study conducted to assess the SP?ti?! yeri?tion of mecrophvte distribution 2nd water quality parameters of a rehabilitated and non-rehabilitated areas of the Diyawannawa wetland with the aim of identifying suitable macrophyte indicator species for water quality monitonng. Sites A, B and C were located in non-rehabilitated area and the sites D, E and F were located in rehabilitated areas in Diyawannawa wetland. The sampling was conducted from April to October 2016. At each site, water pH, temperature, conductivity, sa!inity, total dissolved solids (TDS), dissolved oxygen concentration (DO), biological oxygen demand (BOD5), chemical oxygen demand (COD), depth, visibility, total nitrate (TN), chlorophyli a (Chl a) and total phosphorus (TP) concentration were measured and the percentage cover of macrophytes were recorded. The correlation of percentage cover of macrophyte species to the water quality parameters were assessed using Pemson's correlation analysis. Principal component Analysis (PCA) based on the percentage cover of macrophyte species was performed to identify the characteristic species at each site. M[NITAB 14 software was used for statistical analysis ofdata. The percentage cover of Hydril/a verticil/ata, Pistia straiiotes and Cypreus iria did not show significant spatial variations among rehabilitated and non-rehabilitated areas. Significantly high percentage cover of Nymphaea ampla (64%) and Annona glabra (l I %) were recorded in site A in non-rehabilitated area. Eichhornia crassipes (22%) showed significantly high percentage cover in site B in non- rehabilitated area and site E in rehabilitated area. Cryptocoryne wendtii recorded significantly high percentage cover In sites A (10%) and E (7%), The highest mean percentage cover of Salvinia ;nolesta (30%) were recorded in site E. The spatial variation of physico chemical parameters Indicated significantly high DO in sites E (10.61 mg/l) and F (10.28 mg/l). Significantly high Chl a concentrations were recorded from sites B, E and F. In addition, site F recorded significantly high BOD5 (6.56 mg/l), TN (0.04 mg/l) and COD (454.8 mg/l). There was no significant spatial variation of TP among sampling sites. S. molesta and E. crassipes showed positive correlations with Chl a and TP and N. rubra showed a positive correlation with TN. H. verticillata and P. stratiotes did not show significant correlations with water quality parameters. According to PCA, considering PC scores I to 3, site A in the non-rehabilitated area was characterized by N. ampla and C. wendtii, site B by E. crassipes and P. stratiotes and site C by A. glabra. In rehabilitated area, site D was characterized by C. iria and Ceratophyllum demersum, site E by S. molesta and site F by N, rubra. The PCA based on water quality parameters grouped the sites E and F together and were characterized by high TN and Chl a concentrations. The results of the present study indicated that there is significant spatial variation of percentage macrophyte cover in relation to water quality parameters. Further, this study identified S. molesia and Eichhornia crassipes and N. rubr.a as suitable indicator of Chl a and TP and TN in wetland health monitoring studies.
Sustainable tourism development in Negombo coastline: An option for co-management
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Panagoda, P.A.B.G.; Dissanayake, D.M.S.N.; Nawalage, N.M.S.K.; Silva, H.K.A.D.; Tharaka, L.K.D.N.; Weerasinghe, H.W.G.A.S.; Bellanthudawa, B.K.A.; Kawshalyani, P.; Subanky, S.; de Silva, P.K.S.; Chandrasekara, W.U.
The Negombo coastline is a highly populous area on the west coast of Sri Lanka, and its northern sandy extremity is very popular among the local and foreign tourists. A field survey based on face-to-face interviews with the stakeholder segments was conducted in August 2015 to assess their role and contribution to the management, utilization and governance of this coastline and, to propose suitable management options. In this survey, information from the local stakeholder coastal community (n = 15) including a leading tourist hotel in the area was collected. In addition, information from the chief executive officers of Regional office of the Coast Conservation and Coastal Resources Management Department (CC & CRMD), Negombo Municipal Council (MC) and the Police Station (PS) were collected. The information from the survey were analysed and a SWOT analysis was carried out. The major strengths of the coastline were the presence of an extensive sandy beach and fish resources (78%) and utilization of these resource for income generation (98%), involvement of a large proportion of the local population in tourism (75%), high income gained by tourism (73%), frequent beach cleaning programmes performed the stakeholders (69%), high cleanliness of the beach (75%), high level of education of the local community (63%) and community participation in beach cleaning programmes (62%). The local government authorities are responsible for managing the beach; the CC & CRMD is responsible for preventing coastal erosion and illegal constructions within the beach façade; the MC regularly monitors the sewage discharges and cleanliness of the coastline; the local PS strictly ensures law and peace in the area. The major weaknesses were inadequate government involvement in beach maintenance (69%), lack of awareness and commitment (58%) and willingness (24%) of the local community in community based management (24%). Lack of coordination among CC & CRMD, MC and police over the governance of the coastline was another major weakness. The major opportunities were the possibility expand tourism related activities (25%) and improve cleanliness of the beach (25%). The major threats were the improper solid waste disposal in the coastline (48%), and high taxes against tourism related income generation activities (70%). In addition, child abuse by tourists, drug and liquor trafficking, high coliform count in sea water and coastal erosion were other the major threats. This survey highlights the importance of reinforcing an understanding between the local community and local government authorities over the management and governance of coastal resources in Negombo coastline. Therefore, formulating and strengthening a genuine co-management strategy is highly recommended for the sustainable tourism in this coastline.