University of Sri Jayewardenepura: Journals & Proceedings
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Assessment of Species Diversity of Reef Fishes Impacted by Upwelling in Southern Sri Lanka
Get PDFReef ecosystems play a vital role in marine biodiversity, serving as important habitats for a wide variety of fish species. However, these ecosystems are highly susceptible to the adverse effects of climate change, particularly fluctuations in temperature. In the southwest monsoon of 2024, the coastal upwelling along the southern coast of Sri Lanka, which occurred from end of July to mid of August, had a devastating impact on reef fish species. As a result of the sudden influx of cold water, many reef fish species were unable to tolerate the abrupt drop in temperature. According to the NASA Ocean color images the surface temperature falls between 23.5 -25.5 0C. This led to distressing outcomes, with some fish floating to the surface due to cold shock, while others succumbed to the extreme conditions and perished.This study aims to evaluate the species diversity of died reef fishes across the nine sampling sites along the coastal area of the south coast from 31st July to 25th August 2024. Data collected through physical observations and social media platforms and also species identification performed following the morphological traits and aided by standard taxonomic guides.The highest species diversity was recorded in the Thalaramba coast, with 24 species, followed by Bundala 17, Pareiwella 13 species, Rekawa and Godawaya recorded 9 species in each, Habaraduwa 8, Mirijjawila 7 and Welipatanwila 5 species. A total of 45 species, belonging to 20 families, were identified. The families Balistidae and Pomacanthidae were the most prevalent, with 8 species each, followed by Acanthuridae with 5 species and Chaetodontidae and Lethrinidae with 3 species each. Caesionidae, Lutjanidae, and Scorpaenidae were represented by 2 species each. Additionally, 1 species each from Holocentridae, Labridae, Leiognathidae, Mullidae, Ostraciidae, Pempheridae, Scaridae, Serranidae, Siganidae, Soleidae, Stomopneustidae, and Zanclidae were documented. Centropyge multispinis was the most abundant species, comprising 12.03% of the total, followed by Apolemichthys xanthurus (8.6%), Centropyge flavipectoralis (8.2%), Balistapus undulatus (7.2%), Chaetodon decussatus (5.84%), Zanclus cornutus (5.5%), Pempheris sp. (4.81%), Sufflamen chrysopterum (4.47%), Melichthys indicus and Odonus niger (3.8% each), and Balistoides viridescens (3.44%). This study reveals notable variations in species diversity across different coastal areas, with Thalaramba displaying the highest diversity. The predominance of certain families suggests ecological resilience; however, continued monitoring is crucial to assess the long-term effects of environmental changes. This research highlights the importance of conserving reef habitats to sustain marine biodiversity in Sri Lanka.
Keywords: Reef fish, Species diversity, Cold-water conditions, Southern Sri Lanka, Coastal ecosystem
Investigation of the Decomposition Rate of Gliricidia Sp, Murraya Sp, and Cynodon Sp under Different Abiotic Factors
No full textThe efficient decomposition of organic matter is fundamental to maintaining healthy and productive agricultural ecosystems and establishing a sustainable bioeconomy that maximizes resource utilization and minimizes waste. It directly influences nutrient cycling, soil health, and crop yields. Understanding the decomposition rates of organic matter is crucial for developing effective waste management strategies, as it directly influences the generation of greenhouse gases and the overall environmental impact of organic waste. This study aims to analyze the key factors governing decomposition rates in natural environments by investigating the decomposition rates of Gliricidia sp., curry leaves (Murraya sp.), and grass (Cynodon sp.) under varying abiotic factors. A total weight of 635.00 g 12 litter bags with holes for ventilation were prepared using 600.00 g of soil and 35.00 g of leaves. The selected leaves, Cynodon sp., Gliricidia sp., and Murraya sp. were piled on the soil layer in the litter bags. Three setups containing Gliricidia sp. were monitored separately for water availability, pH, and light intensity. One control setup was kept without any changes. The same procedure was repeated to the other two types of leaves and 3 replicates from each setup were used to get measurements. Water availability was measured using the mass difference of every other day. Initial pH was maintained at 3.8 using Bilin extract, the initial set pH value was maintained, and the decomposition rate was compared with the control. The decomposition rate was measured using the heights of the mixtures and weight differences every other day. Based on our findings, Glyricidia sp. shows the highest decomposition rate in response to changes in each abiotic factor. It exhibits the highest rate of decomposition with variations in light intensity. Compared to the control conditions, all three plant species show the highest decomposition rates at an acidic pH of 3.8. A reduced rate of decomposition is shown among all species when water availability varies. Also, this suggests that acidic conditions significantly enhance decomposition, whereas fluctuations in water availability tend to impede the process. The findings of this study provide valuable insights into the factors that influence the decomposition of organic matter, which can be applied to improve composting practices and other waste management initiatives, ultimately contributing to pollution control and environmental sustainability.
Keywords: Decomposition, Abiotic factors, Organic matter, Ecosystem, Nutrient cycling
The Impact of Avicennia marina Root Density on Leaf Litter Retention and Soil Carbon Variation
No full textAvicennia marina, an abundant mangrove species, contributes significantly to soil carbon by falling leaf litter, but its retention could potentially cause sinking carbon to adjacent soil. The knowledge about the impact of dense roots on leaf retention and subsequent soil carbon variation is limited. The pencil roots of Avicennia marina trees could also support leaf litter retention and soil carbon. But it has not been tested this far. The role of Avicennia marina pencil root density on leaf litter retention and soil carbon in the soil is unknown. The current study aimed to address the relationship between leaf litter retention, root density, and surface soil carbon change in the Avicennia marina microhabitat. The objectives used for this were to determine whether there is a relationship between leaf litter retention along with different root densities, correlating a relationship between root density and soil carbon variation in the Avicennia marina by evaluating soil carbon content at different depth layers. The data were collected in an Avicennia marina micro habitat in the mangrove forest area adjacent to the Rekawa lagoon from November 23rd to December 23rd, 2023. Nine random quadrats (50cm×50cm) were demarcated at the microhabitat with different root densities. All the leaf litter was collected, and the total dry mass of each quadrant was calculated. Root densities were calculated as the number of roots per 1m2. Carbon content of soil samples obtained from a 0-15cm depth layer were evaluated by Loss On Ignition (LOI) at 450 ºC for 4 hours. According to the linear regression tests, the total dry mass of the leaf litter for (50cm×50cm) plots had shown a significant negative relationship (p<0.05) between root densities and the leaf dry masses but there was no significant relationship (p>0.05) between root density (no. of roots per 1m2) and carbon in each soil layer (g), measured as relative to the average surface level as 0-5, 5-10, 10-15 cm. According to the two-way ANOVA test, core carbon content significantly varied between the nine quadrates (p<0.05) but not between the three different layers (p>0.05). Decline of leaf litter content with increasing root density per quadrant shows decreasing the number of roots enables more leaf litter to accumulate and improve the carbon sinking potential. But there is no significant change of carbon in the soil layers. However, there is a significant difference in soil carbon content between each root density.
Keywords: Soil carbon, Avicennia marina, Root density, Leaf litte
Mapping Seagrass Distribution and Determining Species Composition in the Jaffna Peninsula, Sri Lanka: A Spatial Analysis
No full textSeagrasses are marine angiosperms that grow under partially or fully immersed conditions and make up a crucial component in the coastal marine environment. However, seagrass ecosystems are under severe threat by natural and anthropogenic activities, which need to be managed. The spatial distribution and the species composition of seagrasses of the Jaffna peninsula are poorly understood. Therefore, the objective of this study was to estimate the spatial distribution and estimate the species composition and abundance (Ground cover) around the Jaffna peninsula. The fieldwork for this study was conducted in 300 m intervals along the coast. The percentage cover of seagrasses was recorded using Coral Point with Excel Extension (CPCe version 4.1) software to estimate their distribution pattern through ArcMap (version 10.8). Out of the fifteen-seagrass species found in Sri Lanka, seven species from six genera were recorded in the study area: Cymodocea serrulata, C. rotundata, Halodule pinifolia, Syringodium isoetifolium, Thalassia hemprichii, Halophila ovalis, and Enhalus acoroides. Also, the study showed that the Western part of the Jaffna (9.77N, 79.90E-9.65N, 80.04E) has the highest seagrass cover (91.9%) and the Southern part (9.65N, 80.04E-9.52N, 80.49E) had the highest species diversity (1.75) according to the Shannon-wiener diversity index. An average of (0.88) seagrass species diversity was observed in the Jaffna peninsula. The distribution pattern of seagrass species showed that there is a significant difference (p<0.05) in the mean percentage cover among the different sites. Through the observations fishing practices, boating, Mariculture farms, and Boat anchorages are the main anthropogenic stressors around the coast, these findings give the essential baseline data, supporting the targeted conservation and management strategies to protect and sustain the seagrass beds important to Jaffna Peninsula’s coastal ecosystem.
Keywords: Anthropogenic impacts, Seagrass, Distribution, Diversity, Jaffna peninsul
Selection of Suitable Landfill Site in Colombo District, Sri Lanka using Geographical Information Systems (GIS) based Multi-Criteria Decision Analysis (MCDA)
No full textWith urbanization, waste disposal has become an emerging problem in the modern world. Therefore, landfill sites have become a popular solution for this. Disposal of urban waste was a serious problem in the Colombo district, Sri Lanka, and it led to catastrophic events like the Meethotamulla garbage landslide. Landfill site selection is a complex task, and many different factors need to be considered. Therefore, the use of Geographical Information Systems (GIS) emerged as a powerful method for the selection of suitable landfill sites. This study aims to identify suitable landfill sites in the Colombo district using GIS with Multi-Criteria Decision Analysis (MCDA). The whole Colombo district was selected as the study area. In this study, road network, river network, soil type, and proximity to towns were considered as the main criteria. Each layer was assigned equal weight using the Analytical Hierarchy Process (AHP) to ensure efficiency and well-balanced weightage of the factors influencing the suitability of the site. The weighted overlay analysis was applied to combine the spatial data, and the generated suitability map was categorized into four classes: restricted, least suitable, suitable, and most suitable areas using ArcGIS 10.8. The results of the analysis reported that a total area of 362 km² of the Colombo district was restricted for landfill use, because of its proximity to sensitive locations such as water bodies and densely populated areas. Only 1 km² was identified as the least suitable area and it suggests that minimal potential in this category. The suitability map identified that 179 km² was suitable for landfill dumping, while 122 km² area was determined to be the most suitable. These most suitable areas are the areas that provide the best combination of access to road and transportation networks, adequate distance from water bodies and towns, and favorable soil conditions for sustainable landfill development. This study efficiently demonstrates the effectiveness of using MCDA in GIS for landfill site selection, providing a good approach to balancing environmental, social, and economic aspects. The results of this study will be important for policymakers and urban planners in the Colombo district in selecting potential locations for sustainable waste management to reduce the environmental impact of improper landfill site selection. Future research could be expanded by adding additional factors, such as geology and rainfall factors, etc.
Keywords: Landfill site selection, GIS, MCDA, Colombo district, Waste management
 
Factors Influencing the Willingness to Pay for the Establishment of a Proper Collection Facility for PET Bottle Waste in the Western Province, Sri Lanka
No full textPolyethene Terephthalate (PET) is one of the common types of plastics that is utilized for packaging materials in Sri Lanka. Excessive production, consumption, and disposal of PET bottles have become an environmental burden due to a lack of collection facilities and proper end-of-life management. Therefore, recycling PET bottle waste is critical to sustainable waste management practices, especially in regions like the Western Province of Sri Lanka. Hence, the current study attempted to understand the major factors influencing consumers’ intention to recycle PET bottle waste and identify the influence of intention to recycle PET bottle waste on the willingness to pay for the establishment and maintenance of a proper collection facility. The proposed model was based on the Theory of Planned Behavior and Value Belief Norm (VBN) theory. Face-to-face interviews were conducted in Colombo, Gampaha, and Kalutara districts, covering the Western province of Sri Lanka. The final sample consisted of 202 respondents. Partial Least Square Structural Equation Modelling (PLS-SEM) was employed for data analysis. The findings of the study revealed that environmental knowledge has a positive, significant effect on attitudes and recycling intention, while attitudes have a positive, significant influence on recycling intention. However, subjective norms and moral norms have a negative, significant effect on recycling intention. In addition, recycling intention has a positive, significant effect on the willingness to pay to establish the collection facility. In addition, attitudes mediated the relationship between environmental knowledge and the recycling intention towards PET bottle waste. Moreover, findings showed that 64% of the respondents still use open burning of PET plastic bottle waste as a disposal method despite the ban on plastic burning. Therefore, this study provides insights to help the government, policymakers, and other waste management authorities to understand the behavioral aspects related to recycling PET bottles and formulate strategies to enhance PET bottle recycling rates, contributing to a cleaner and healthier environment.
Keywords: PET bottle waste management, Willingness to pay, Intention for recycling,
PLS-SEM.
 
Urban Water Conservation in a Changing Climate: The Impact of Temperature and Precipitation on Urban Household Water Consumption
No full textNowadays, water has become a limited and crucial resource, and the demand and consumption of water are increasing day by day due to rapid population growth and urbanization. Therefore, understanding the factors that influence household water consumption is crucial for effective water resource management. While previous research in Sri Lanka has primarily explored socioeconomic and demographic factors, the impact of environmental variables such as temperature and precipitation has been relatively overlooked. This study aims to fill this knowledge gap by investigating the relationship between climatic factors and household water consumption patterns in the country. The effect of temperature and rainfall on the monthly average water consumption of fifty household units selected by judgement sampling in the Jinthupitiya Grama Niladhari Division of Colombo was assessed. The main objective was to identify the temporal variation in water consumption. Time series analysis was used to identify the temporal variability of water consumption in the study area, and multiple regression analysis and the Pearson correlation coefficient were used to identify the relationship between climatic variables and water consumption. As a result of statistical analysis, Pearson's correlation coefficient revealed that there is a negative correlation between rainfall and water consumption (r=-0.04, Sig. 0.78) and a positive correlation between temperature and water consumption (r=0.285, Sig. 0.09).Considering the effect of climate on water consumption, it can be recognized that a clear decrease in water consumption is shown in the months with high rainfall and an increase in water consumption is shown in the dry months with low rainfall, and also a higher temperature shows an increase in water consumption during dry months. However, due to the rapid population growth in urban areas, the demand for water is increasing, and providing a supply that meets the demand will be a challenge in the future. As the intensity and frequency of hydrological extreme events may increase due to the impact of climate change conditions in the future, a major water crisis may arise. Therefore, the need for sustainable water management has been highlighted today. For that, it is more effective to refer to household water management and conservation strategies with a broad community participation approach.
Keywords: Household water consumption, Precipitation, Temperature, Population growth, Sustainable water managemen
Spatial and Temporal Variation of Litter along Some Selected Beaches of the West Coast of Sri Lanka
No full textBeach litter is a growing environmental issue affecting coastal ecosystems and communities. Coastlines that are influenced by monsoonal patterns, human activities, and river openings experience significant spatial and temporal variations in litter pollution. The aims of this study were to assess the litter pollution on 05 selected beaches along the west coast of Sri Lanka (viz. Negombo, Modara, Moratuwa, Panadura, and Kalutara beaches) and to evaluate how the beach morphology (viz. beach width and slope) and the season of the year (viz. dry season and rainy season) influence the extent of their litter pollution. The abundance of different types of beach litter including plastic items was recorded within 5m×5m quadrats established at random locations (n=5) on each beach during the dry season (e.g., 2nd week of August to 1st week of October 2023) and the rainy season (e.g., last week of December 2023 to 1st week of February 2024). The width and slope (n=5 each) of each beach were determined during both seasons using standard methods. The seasonal and spatial abundance of beach litter was analyzed using two-way ANOVA. The seasonal and spatial diversity of beach litter was analyzed using the Shannon-Weiner diversity index (H’) and Pielou’s evenness index (J’). The relationship between beach litter diversity and beach morphology was analyzed using regression analysis. Plastic litter in terms of total abundance (N=10551 pieces) and percentage abundance (93.76%) dominated the beach litter on all beaches during both seasons. The abundance of the large plastic category was significantly higher (p<0.05) during the rainy season than in the dry season. The highest and the lowest abundance of the large plastic category were recorded at Modara (N=3226) and Kalutara (N=398) beaches, respectively. Overall, the highest beach litter diversity (H’ and J’) was recorded at Kalutara beach during both periods. Negombo beach was the steepest and widest (p<0.05). Though not significant, the litter diversity showed decreasing trends with the increasing beach slope and beach width during both seasons. Plastic litter was the most abundant litter category during the rainy season, highlighting how seasonal factors influence litter accumulation on the beach. The high abundance of large plastic litter (i.e., Modara) and increased diversity of beach litter (i.e., Kalutara beach) may be attributed to the rainfall and the associated surface runoff from the nearby Kelani River (e.g., Modara beach) and Kalu River (e.g., Kalutara beach), tourism, and the absence or insufficient beach cleaning practices.
Keywords: Beach slope, Beach width, Judgmental sampling, Plastic pollution, Seasonal variatio
Assessing the Efficiency of Floating Wetland for Nutrient Remediation in Pond Water: Case Study
No full textThe proper management and handling of water containing high nutrient concentrations is essential in rehabilitation of harmed pond ecology and more for the environment as a whole. In this research, researchers seek to assess to what extent Constructed Floating Wetlands (CFWs), can be used as an eco-friendly technique to treat water from nutrient-rich ponds. CFWs use water plants with firm roots to remove and minimize the wastes and pollutants which include excessive nutrients. The three selected Endemic Sri Lankan plants namely Massula angustifolia, Coix lacryma-jobi (Kiridi), Eriocaulon ceylanicum (Kokmota) were tested for 49 days. These species were chosen because they are found locally as endemics/natives, have already demonstrated phytoremediation ability, are adapted to polluted water environments and are growing rapidly and are easy to manage. These traits make the plants effective in nutrient uptake and suitable for utilization in CFW systems. Plant acclimatization as well as earlier studies that showed that the plant could remove pollutants within 49 days were used to determine this value. This study was carried out in a controlled laboratory setup, and three tanks were constructed to represent the functional FWSs through replication, and the systems’ capability to remove Eutrophic Pond water was examined. Different samples have achieved different efficiency and Massula angustifolia was able to remove pollutants at varying efficiency like TDS of 24.14%, turbidity of 85.71%, TSS of 89.33%, nitrite at 55.82%, nitrate at 84.72%, phosphate at 98.51%, COD at 88.89%, ammonia at 92.70%, and BOD at Coix lacryma-jobi and Eriocaulon ceylanicum were equally efficient with the removal of phosphate at rates of up to 97.42% and 96.66% respectively. The paper points to the fact that these plant species can be used in the reclamation of water in the eutrophic pond water hence acting as an economic way of supporting the treatment of domestic and freshwater bodies in the developing world.
Keywords: Reclamation, Eutrophication, Constructed floating wetlands, Aquatic ecosystem
Twenty-Five Years of Democracy in Nigeria, 1999- 2024: A Reality or a Sham?
Get PDFThere are several studies on Nigeria’s democracy. However, such academic inquiries have not debated whether the last twenty-five years of democracy are a reality or a sham. This study was conducted to fill the knowledge gap that the existing literature has created. Using secondary sources consistently with interdisciplinary methods, the study delves into the history of democracy in Nigeria. It analysed the benefits of democracy in Nigerian society in the previous twenty- five years. The infelicities linked with the practice of democracy in Nigeria during the time under evaluation are also espoused. The study recommended solutions capable of restoring democracy in the country. It concluded and maintained that democracy has not provided adequate dividends to the Nigerian people within the period under review.
DOI: http://doi.org/10.31357/fhss/vjhss.v10i01.06