Zoology
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Item Comprehensive evaluation of demographic,socio-economic and other associated risk factors affecting the occurrence of dengue incidence among Colombo and Kandy Districts of Sri Lanka: a cross-sectional study(Parasites & Vectors (2018) 11:478, 2018) Udayanga, L.; Gunathilaka, N.; Iqbal, M.C.M.; Lakmal, K.; Amarasinghe, U.S.; Abeyewickreme, W.Background: Comprehensive understanding of risk factors related to socio-economic and demographic status and knowledge, attitudes and practices (KAP) of local communities play a key role in the design and implementation of community-based vector management programmes, along with the identification of gaps in existing control activities. Methods: A total of 10 Medical Officers of Health (MOH) areas recording high dengue incidence over the last five years were selected from Colombo (n = 5) and Kandy (n = 5) Districts, Sri Lanka. From each MOH area, 200 houses reporting past dengue incidence were selected randomly as test group (n = 1000 for each district) based on the dengue case records available at relevant MOH offices. Information on socio-economic and demographic status and knowledge, attitudes and practices were gathered using an interviewer administered questionnaire. The control group contained 200 households from each MOH area that had not reported any dengue case and the same questionnaire was used for the assessment (n = 1000 for each district). Statistical comparisons between the test and control groups were carried out using the Chi-square test of independence, cluster analysis, analysis of similarities (ANOSIM) and multidimensional scaling (MDS) analysis. Results: Significant differences among the test and control groups in terms of basic demographic and socio-economic factors, living standards, knowledge, attitude and practices, were recognized (P < 0.05 at 95% level of confidence). The test group indicated similar risk factors, while the control group also shared more or less similar characteristics as depicted by the findings of cluster analysis and ANOSIM. Findings of the present study highlight the importance of further improvement in community education, motivation and communication gaps, proper coordination and integration of control programmes with relevant entities. Key infrastructural risk factors such as urbanization and waste collection, should be further improved, while vector controlling entities should focus more on the actual conditions represented by the public on knowledge, attitudes and personal protective practices. Conclusions: The design of flexible and community friendly intervention programmes to ensure the efficacy and sustainability of controlling dengue vectors through community based integrated vector management strategies, is recommended.Item Ancient Reservoirs of Sri Lanka: A Modern Biological Resource for Assuring Food Security in Rural Communities(University of Kelaniya, 2005) Kularatne, M.G.; Amarasingha, U.S.Reservoir construction in Sri Lanka dates back to times even before the period of written history. In Sri Lanka (64,652 km2), there are over 200 large (750 – 7,793 ha) and medium-sized (250 – 750 ha) reservoirs with a cumulative extent of over 130,000 ha, which support capture fisheries. In addition, there are over 15,000 small (<50 ha) village reservoirs with a total extent of about 39,000 ha. The reservoir density in Sri Lanka (about 2.6 ha for every km2 of island) is one of the highest, if not the highest in the world. Almost entire reservoir resource in Sri Lanka, with the exception of recently constructed hydroelectric reservoirs, supports agricultural food production in the country. As the extent of perennial reservoirs in each district is directly related to per capita freshwater fish consumption, in addition to agricultural production, major perennial reservoirs of Sri Lanka support animal protein production in the form of fish production. This is of particular importance because marine fish consumption is much low in inland districts possibly due to the availability of good quality freshwater fish locally. Also, there is a significant potential for the development of culture-based fisheries in small, village reservoirs of the country. An average fish yield of about 450 kg ha-1 can be achieved during a single culture cycle within a year from the culture-based fisheries in these village reservoirs. However, in order to achieve success of this strategy, a strong extension mechanism is needed to obtain active community participation. As inland fishery is a source of relatively cheap animal protein for rural communities, future prospects of this sector for food security need to be properly understood to give a high priority for inland fisheries research and development in national development plans.Item Application of pollution indices to quantify the pollution status of shallow sediments of the Bolgoda Lake, Sri Lanka(National Science Foundation of Sri Lanka, 2016) Wijeyaratne, W.M.D.N.The present study was conducted to assess the pollution status of the shallow sediments of the Bolgoda Lake in Sri Lanka using sediment pollution indices. Shallow sediment samples were collected as replicates from five sites with different land uses in the monsoonal and nonmonsoonal seasons in 2013. The samples were acid digested and analysed for Cd, Cr, Cu, Ni, Fe and Zn. The heavy metal concentrations were used to calculate: (1) contamination factor (Ci f ); (2) degree of contamination (Cd); (3) pollution loading index (PLI); (4) enrichment ratio (ER); (5) geoaccumulation index (Igeo) and (6) ecological risk factor (Eri ) of the shallow sediment samples. In addition, the quality of the sediments were also assessed by comparing with the numerical sediment quality guidelines (SQGs) and consensus-based sediment quality guidelines (CBSQGs). Significant spatial variations of element concentrations and sediment quality indices were identified in the study area. The pollution level of the study sites ranged from unpolluted to heavily polluted due to heavy metals. The contamination factors for all the heavy metals except Zn indicated moderate, considerable or very high level of pollution in both sampling sessions. The potential ecological risk factor for the heavy metals ranked as Cd > Ni > Cr > Cu > Zn for both sampling sessions indicating the highest potential ecological risk from Cd. The pollution load index for all the study sites except site E in both sampling sessions showed human associated pollution with a PLI higher than 1. All the samples were categorised into class 1 (unpolluted to moderately polluted status) with respect to Cr, Ni, Cu and Zn and to class 0 (unpolluted status) with respect to Cd. The concentrations of Zn and Cd in the present study were lower than the threshold effect concentration (TEC) level of CBSQGs and therefore, was indicated as unlikely to be causing toxicity to benthic organisms. The concentrations of Cr and Ni were higher than the probable effect concentration (PEC) level of CBSQGs and indicated a probable toxicity to benthic organisms.Item Monitoring eutrophication trends in Bolgoda North Lake, Sri Lanka by Satellite Remote Sensing(Central Fisheries Research Institute (CFRI) Trabzon, Turkey in cooperation with Japan International Cooperation Agency (JICA), Japan, 2016) Dahanayaka, D.D.G.L.; Perera, B.D.C.; Wijeyaratne, M.J.S.; Tonooka, H.This study was aimed to determine the present level and past trends of eutrophication of the Bolgoda North lake, Sri Lanka using in situ Chlorophyll-a (Chl-a) measurements and remote sensing data obtained from Advanced Space-borne Thermal Emission and Reflectance Radiometer (ASTER) satellite data. From March to October 2013, Chl-a, nitrate and phosphate contents of the lake were measured once a month on the days of ASTER overpass and using standard laboratory methods. Cloud-free ASTER images of the lake for the 2000-2013 period were atmospherically corrected using Fast Line-ofsight Atmospheric Analysis of Hypercubes (FLAASH) and in-situ Chl-a data were regressed with atmospherically corrected three ASTER Visible and Near Infrared band ratios of the same date. The green/red band ratio, which had the highest coefficient of determination, was used to develop algorithm for generation of 15-m resolution Chl-a distribution maps. Results indicated that eutrophication of this lake has increased from 2008 to 2011. Heavy eutrophic conditions were noted in several regions of the lake in 2013, especially in water stagnant areas and adjacent to freshwater inlets. Unplanned urbanization and inadequate facilities for waste management have resulted in heavy eutrophication of the water body. If the present trends of waste disposal and unplanned urbanization continue, enormous environmental problems would be resulted in future.Item New species of the Pristomyrmex profundus Wang group from the Oriental Region (Hymenoptera: Formicidae: Myrmicinae)(2016) Yamane, S.; Dias, R.K.S.Two new species of the ant genus Pristomyrmex Mayr belonging to the P. profundus Wang group are described from the Oriental Region: P. leleji Yamane et Dias, sp.n. from Thailand, and P. sinharaja Dias et Yamane, sp.n. from Sri Lanka. A key to species of the Pristomyrmex profundus group is presented.Item External Quality Assessment of Higher National Diploma Programmes Offered in Sri Lanka: An Account of Best Practices(South Eastern University of Sri Lanka, 2013) Bandara, T.H.S.S.; Wijeyaratne, M.J.S.Quality assurance activities that are carried out in the Sri Lankan university system since 2002 were introduced to the alternative higher education sector in 2010. External quality assessment reviews of Higher National Diploma (HND)programme offered in eleven Advanced Technological Institutes (ATIs) located in different regions of the country were carried out to identify the best practices, strengths and weaknesses and make suitable recommendations to improve the quality of those programmes. The aspects reviewed were curriculum design, content and review; teaching, learning and assessment methods; quality of students, their progress and achievements; use of student feedback; peer observation; skills development; and academic guidance and counseling. The objective of the present study was to determine whether there are regional differences among ATIs when best practices that are in place in different HND programmes are considered. Best practices identified by the reviewers in external quality assessment review reports of HND programmes in Accountancy, Agriculture, Business administration, English, Information Technology and Management conducted in Ampara, Dehiwala, Jaffna, Kandy, Kegalle, Kurunegala, Labuduwa and Trincomalee ATIs were analysed using Principal Component Analysis to determine whether there are regional differences among ATIs with respect to best practices that are in place in each programme. Results indicated that the good practices identified by reviewers in different HND programmes do not depend on the location of the ATI, the ethnicity of the majority community and prevalence of deterrent factors such as armed secessionist conflicts in the area. Differences in the resources available and the motivation and dedication of the staff may have contributed to the differences in the good practices that are in place in different ATIs.Item Indigenous knowledge in the beach seine fisheries in Sri Lanka: An indispensable factor in community-based fisheries management(Journal of Marine Policy, 2015) Deepananda, K.H.M.A.; Amarasinghe, U.S.; Jayasinghe-Mudalige, U.K.Small-scale fishing over the globe is based primarily on fisher indigenous knowledge (IK), accumulated through many generations of close interactions between people and the natural world. Community-based beach seine fisher communities of southern Sri Lanka were studied through standard ethnographic methods to ascertain the traditional method in using fishers’ IK, and explore empirically the accuracy in using those methods distilled from the traditional fishers. Study revealed that, inter alia, traditional fishers use IK to predict the commencement of fishing season, and identify and quantify the species composition occurring at their fishing territory. Ten traditional methods those which are important for identifying and quantifying the fish school were distilled. Explored methods frequently used by traditional fishers were based on the changes of seawater color (folk oceanography) and the behaviour of sea terns (Sterna sp.). Traditional fishers’ responses on frequency of utility of explored methods in day-to-day fishing activities were in accordance with the findings of the empirical study. Moreover, principal component analysis (PCA) revealed that PC score loading in fishers’ expectation and fishers’ realization had a positive significant relationship (r=0.814, p<0.001). This indicated that traditional fishers’ expectation on composition and quantity of fish school arriving at fishing territory (ex-ante) is accurate and reliable at the realization (ex-post). As such, there exist opportunities to fisheries co-management for the coastal fisheries in Sri Lanka, incorporating fishers’ indigenous knowledge in resource exploitation.Item Coastal water body database to monitor the water quality and land use changes from remote sensing data(Remote Sensing Society of Japan (RSSJ), 2012) Dahanayaka, D.D.G.L.; Tonooka, H.; Wijeyaratne, M.J.S.; Minato, A.; Ozawa, S.Item Feasibility Study for the Estimation of the Chlrophyll-a Using ASTER Data in an Eutrophic Lake, Sri Lanka(Japan Geoscience Union, Japan., 2014) Dahanayaka, D.D.G.L.; Tonooka, H.; Wijeyaratne, M.J.S.; Minato, A.; Ozawa, S.The objective of this study is to evaluate the performance of the previously proposed band ratio approach in estimating Chl-a in Bolgoda Lake, Sri Lanka as a representative example of Case II waters. Lake is located at western province in an area with lot of industries and also with some agricultural activities. Considerable amount of industrial effluents are discharged into it. Illegal filling and also encroachment has occurred in the recent past. This study focused on to determine the trends in eutrophication via Chl-a changes during the recent past, make predictions and recommend mitigatory measures and suggest precautionary measures to restore the environment. From March to December 2013, water samples at 5 points of Lake were collected once per month parallel to ASTER overpass and Chl-a of each sample was measured using a laboratory spectrophotometer. Cloud-free ASTER scenes acquired over Lake under clear sky conditions were selected during 2000 to 2013 for Chl-a estimation and trend analysis. All the ASTER images were atmospherically corrected using FLAASH and in-situ Chl-a data on Lake were regressively analyzed with atmospherically corrected three ASTER VNIR band ratios such as B1/B2 of the same date. Finally, the regression equation of the band ratio with highest correlation (B1/B2; R2 = 0.78) was used to develop algorithm for generation of 15-m resolution Chl-a distribution maps using atmospherically corrected time series satellite imageries in day by day basis. This method applied for ASTER band 1/2 ratio due to Chl-a is positively correlated with the green band reflectance and negatively correlated with the red band reflectance. Therefore, the reflectance ratio of green and red bands becomes a robust parameter to estimate the Chl-a content. According to the ASTER based Chl-a distribution maps it is clearly evident that eutrophication of the Bolgoda Lake has been gradually increased from 2005-2011. Further, results showed that there were significant eutrophic conditions throughout the year 2013 in several parts of the Lake and considerable spatial heterogeneity with higher concentrations being recorded water stagnant areas and in water adjacent to freshwater outlets. It is clear that Bolgoda Lake is apparently a disposal site of various discharges of factories in addition to poor drainage and sewage systems present in this area. Highly unplanned urbanization and absolutely lack of adequate waste disposal management facilities in industries close to Lake have resulted in pollution of water. If the present trend of waste disposal and unplanned urbanization continue, they would create enormous environmental problems in future. Results of the present study showed that information from satellite remote sensing can play a useful role in determining the changes in Chl-a related to eutrophication in Bolgoda Lake and in the development of time series Chl-a distribution maps. Such information is important for the future predictions, development and management of this area as well as in the conservation of biodiversity. Therefore we recommend incorporation with this technique for routine monitoring of water quality using multi satellite data such as ASTER in inland water bodies like Bolgoda Lake in the future.Item Integration of multisource data for chlorophyll-a monitoring in Negombo estuary, Sri Lanka(IEEE, 2011) Dahanayaka, D.D.G.L.; Tonooka, H.; Wijeyaratne, M.J.S.; Minato, A.; Ozawa, S.In order to estimate chlorophyll-a concentration (Chl-a) for tropical coastal estuarine environments using satellite optical sensor, observations were conducted from 1987 to 2009 in Negombo estuary, Sri Lanka, with support with available in-situ measurements. Landsat band ratios were regressively analyzed with available in-situ Chl-a data. This relationship was used for correcting MODIS OC3 Chl-a values, and then ASTER band ratios were regressively analyzed with the corrected MODIS values. The regression equations obtained for ASTER and Landsat were used to develop algorithms for generation of 15m and 30m resolution Chl-a distribution maps, respectively, in Negombo estuary using atmospherically-corrected time-series imageries. The results indicate that some parts of the estuary have increased eutrophication conditions during 1987-2009.