3rd URS-ZEM - 2017

Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/16655

Browse

Now showing 1 - 20 of 26

Preliminary study on carrion frequenting blowflies (Calliphoridae) in three localities in Sri Lanka and their response to formalin treatment
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Athapaththu, A.M.G.K.; Amarasinghe, L.D.; Weerathunga, W.A.M.T.
It is a known fact that formalin is unwarrantedly used to keep harvested fish longer in fresh condition. In this experiment, it was considered how it affects the natural population of blowflies by adding different concentrations of formalin to fish. Diversity of carrion attracting blowflies and its variation with the time was also quantified. Sardinella melanura fish were used. Three different concentrations of formalin (0.1 ppm, 0.01 ppm and 1 ppm) were injected (1.5 mL each) to three fish of same dimensions. The selected concentrations are highly likely to represent the range used by fisherman as 0.1 ppm is considered to be the minimum detectable by human senses. The fish were set in a water bottle bait trap, which were set in two environments (rural and suburban) at mid-elevation (149 m) and in two elevations (mid- and low, 7 m) in suburban environment. Carrion flies were collected daily. They were identified upto species level using pictorial keys, under stereo microscope. A total of 135 blowflies were collected. Cochliomyia spp. (Family Calliphoridae) was the most abundant type of carrion attracting blowfly in all three localities. In addition, housefly (Family Muscidae) was found only from the two suburban elevations. Blowfly diversity in the three localities was calculated separately, using Shannon-Wiener Index (H). The highest diversity was observed in low-elevation, suburban environment (H=1.211) followed by mid-elevation, suburban (H=0.889) and mid-elevation, rural environments (H=0.411) respectively. Availability of a source of blowflies in the neighborhood and favorable conditions to complete their life cycle can be reasons for higher diversity in the suburban environment. However, diversity did not vary significantly (p=0.05) with concentration of formalin injected, with H ranging from 0.938 to 0.983. Multiple regression analysis showed that the cumulative number of blowflies attracted increased with increasing formalin concentration. This could be due to increased concentration of formalin derived from breakdown of nitrogenous compounds as fish rot, plus the added formalin and genetic adaptation of blowflies. The number of blowflies attracted decreased significantly with increasing days after injection because with time the flesh is decomposed and the compounds which attract blowflies are gradually broken down.
Case study on usage of polythene bags in super markets of Colombo metropolitan and finding an alternative
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Athukorala, U.K.; Gamagedara, D.; Gayangani, E.M.; Chrishanthan, J.E.; Bandara, W.A.R.T.W.
Polyethylene bags since their emergence in the 1940s, is an incredibly useful, highly convenient, strong and inexpensive, to both customers and businesses as a reliable way to deliver goods from the store to home. According to statistic, 20 billion polythene bags are being used per day in Sri Lanka. This creates massive amount of non-biodegradable waste which poses a huge threat to human, animal and the environmental health. This study was conducted with the primary objective of evaluating the current usage of polythene in super markets of Colombo District and to find alternatives to minimize the usage of polythene bags in super markets. Primary data were gathered by a questionnaire survey carried out among the four major super market chains as in Cargills Food City, Keells Super, Arpico Super Centre, Laugfs Supermarket to understand the usage of the polythene bags. Secondary data were gathered from observations, discussions, books, electronic media and other sources. Some paper bag alternatives were made; Cement Paper bag with oil paper coating, Cement Paper bag with corn husk as the bottom, Cement Paper bag with oil paper layering and Cement Paper bag with banana tree bark at the bottom to test the mechanical properties and feasibility of the option. The results from the Market survey signifies that averagely around 8 million of polythene bags are issued per month by all the outlets in Colombo district by each super market category. Therefore, study findings revealed that out of the four types of alternatives tested Cement Paper bag with banana tree bark at the bottom would be the best option as it showed the greatest mechanical properties. When look in to the cost associated with the production, all the four types of bags would have to bear the coat of 6.75 to 7.00 LKR. Therefore, Cement paper bag with banana tree bark at the bottom would be the ideal replacement for polythene bags use to pack different types of dry vegetables and food.
Avifaunal responses to habitat fragmentation in three different forest fragments adjacent to Mihintale Sanctuary
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Bopearachchi, D.; Wickramasinghe, S.
Tropical forest fragmentation is considered as the main cause of extinction of tropical forest avifauna and the diversity of birds in fragmented areas are poorly understood. However, in Sri Lanka information on the effects of forest fragmentation on avifauna is scarce. Therefore, the study aimed to determine the avifaunal responses to habitat fragmentation in the three different fragments adjacent to Mihintale sanctuary. The current study was conducted in morning and evening for a period of six months from June to November 2015 and sampling was done in 40 hrs per month in each fragment. Point counts were used for data collection of birds in three different sized isolated forest fragments denoted as FA- fragmented area near Ayurveda, FK –fragmented area near Kaludiyapokuna and FP – fragmented area near Poson Mawatha. Arc GIS was used to measure areas of fragments. While, quadrate sampling method was used for sampling fragment vegetation. Total of 0.51 km2 covered during sampling. Altogether, 85 birds belonging to 37 families were recorded, including 74 breeding residents, 11 winter visitors, 3 endemic and 3 proposed endemic species. The area of three fragments were ranged from 1.1 to 3.4 ha. Species richness in FA was higher compared to the other two fragments in both seasons. Total number of species were significantly different dry-P=0.000, wet-P=0.001 among three fragments. Of the observed birds 18 (35.3%) species were common to all three fragments and five (9.8%), nine (17.7%) and two (3.9%) observed bird species were restricted to FA, FK and FP respectively. The species diversity in wet season was higher compared dry season in all three fragments. There was no significant difference in monthly variation of species diversity in FA and FK, but differed in FP. A total of 29 plant species belonging to 15 families were identified in three fragments. A higher tree and shrub density was recorded in FK. Vegetation was the major attribute positively related to species richness, abundance and diversity in fragments. Hence, protection and restoration of forest fragments may help to mitigate negative effects of fragments on bird functional groups.
Are human-modified land-uses important for avifaunal conservation or not? An example from Karanketiya, Rakwana, Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Weerasinghe, H.W.G.A.S.; Panagoda, P.A.B.G.; Panagoda, P.A.S.U.
Improving conservation value of human-altered landscapes would be of massive importance, in years to come. The present study intended to assess the contribution of such landscapes in aid of conservation of avifauna. Abundance, species richness, species heterogeneity, evenness and composition of bird communities were analyzed on line transects during three months, including the migratory season, in three different land-use types namely, proposed reserved forest, tea estate and home gardens in Karanketiya, Rakwana. Total of 87 bird species including 79 residents with 15 endemics and 8 migrants were recorded. Species richness and total abundance per transect of three types of land-uses are significantly different (p<0.05, ANOVA). Species richness (n=68) was highest in tea estate while species heterogeneity (H’=3.612) and evenness (J’=0.872) were highest in home gardens. Percentage of endemic birds (25.6%) and percentage of migrant birds (12.8%) were highest in the forest and percentage of resident birds (74.6%) was highest in home gardens. The bird species composition in tea estate was highly comparable to that of home gardens (Cj=0.58). Percentage of openland birds (23.5%) was highest in tea estate whereas percentage of forest birds (59%) was highest in forest reserve. In addition, certain specialists were found exclusively within the forest. The higher diversity recorded, in human-modified landscapes has caused by its location in a closer proximity to forested areas and the wider array of different habitat types present. Therefore, such human-modified land-uses contribute for avifaunal conservation in the country. Yet, the long term impacts of such landscapes should be studied further.
Developing a rapid composting machinery system using Berkeley method
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Handapangoda, H.M.A.K.
Municipal solid waste generation and management in most cities especially in developing countries have emerged as one of the stubborn environmental problems at present. This scenario could be attributed to low level of technology as it is not sophisticated and not sufficient to deal with the excessive quantity of waste generation. Recognizing those noteworthy amounts of organic waste fraction of MSW in developing nations like Sri Lanka, there ought to make necessary feasible fitting systems to convert this huge amount into a resource. Composting, one of the environmentally feasible methods that convert organic waste into useful materials brings several drawbacks. This paper suggests a system with computerized automated machineries with the aim of increasing the rate of composting in a comparatively short time period. Berkeley method composting is taken as the principle for this system. The system consists with a shredder, a pill rotator (mixer), an air flow controller, and moisture and temperature controllers. The system is a closed system that implements favorable conditions for the composting process. Air flow, moisture level and temperature can also be controlled in the system. Purpose of shredder is to reduce the size of waste that further facilitate fast composting. Humidity and temperature sensors are used to keep compost pill in optimal level of conditions. Pill rotator (mixer) is rotated periodically in a given time period to facilitate proper mixing to pill. In addition, shredder size, pill rotating time, air supply and moisture and temperature can be changed on waste composition. Advancement of this method is to convert organic materials into usable form in short time period with less space and labor requirement. Energy requirement for the operation process can be generated by solar power is another added advantage of the method. However, further development is needed to overcome bottlenecks and gaps of the system.
Preliminary survey of insect pollinators in the premises of University of Kelaniya
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Madduma, M.D.R.; Ramanayaka, A.R.D.D.; Jayasundara, S.M.J.C.K.; Amarasinghe, L.D.
A study was carried out to identify species of insect pollinators and to determine their percentage occurrence in university premises. These findings can be used to assist with the aims of green university concept by suggesting the most applicable methods to conserve insect pollinators in the area. In this study the plant species were identified in university premises by referring to herbariums and sign-boards of plants to which the pollinators were attracted. To identify different species of insect pollinators, only the insects which were landing on the flowers were sampled using a butterfly net with a diameter of 0.5m and 1m long handle while some species were hand-picked. The percentage occurrences of those species were computed in eight different sites, twice a day; from 8.30am to 10.30am and from 3.30pm to 5.30pm within an observation period of 14 days from 14th-28th October 2016. During the observation period the average relative humidity, temperature and wind speed were respectively 62-65%,2930C,2-4mph. Totally 12 insect species were identified. In site 01, rich with flowering plants; 11 species of insect pollinators were observed out of 12 identified species. In other sites with less vegetation and where the constructions were going on, had less species richness. Butterfly species, Leptosia nina, Ypthima celonica, Eurema hecabe and the bee species Tetragonula iridipennis have a percentage occurrence higher than 75% while rest of the identified insect pollinators have similar or less than 50% of percentage occurrence in university premises. The flies, Bactrocera cucurbitae were only observed in site 01 and 02 where the vegetable plants were present and Bactrocera dorsalis were only observed in site 01 where the most fruit plants were present. Many species among the identified species were observed visiting the plants, Tecoma stans, Cosmos sulphureus, Spatodea companulata,Cassia fistula, Jasminum sambac, Delonix regia. These insect populations can be increased and even new pollinator species can be attracted by introducing preferable flora and using other conservation methods such as building pollinator gardens for those species.
Some aspects of dietary ecology of a community of amphibians in the Mihinthale Sanctuary, North Central province, Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Sarathchandra, R.B.L.R.; Vandercone, R.P.G.; Ukuwela, K.D.B.
An ecological community is an assemblage of interacting populations of species that are interdependent and hence, understanding the conditions under which interacting species can persist is a fundamental problem in ecology. The objective of this study was to examine the trophic relationships between sympatric amphibians in the north central dry zone of Sri Lanka. The amphibian community in and around the Mihinthale Sanctuary(8° 21 ′−8° 30 ′𝑁 𝑎𝑛𝑑 𝐸) was sampled from 6.00 pm to 2.00 am, January to August 2016 and stomach flushing was used to examine the diet of amphibians. Pairwise dietary niche overlap and niche breadth were computed using Simplified Morisot’s and Levin’s standardized niche breadth indices respectively. Seventeen different prey categories were identified from six species of amphibians (Euphlyctis cyanophlyctis, Euphlyctis hexadactylus, Fejervarya limnocharis, Duttaphrynus melanostictus, Uperedon taprobanica, Ramanella variegata) in the community. The most frequently utilized prey category by all amphibians was hymenopterans. Other major prey categories were coleopterans, dipterans, hemipterans and spiders. Highest prey diversity was detected in Euphlyctis cyanophlyctis, while the lowest prey diversity was detected in Ramanella variegata.The average niche overlap among the species in the community was 0.392, indicating very low trophic niche overlap. The highest niche overlap was observed between Uperedon taprobanica and Ramanella variegata (0.453), while the lowest was observed between Euphlyctis cyanophlyctis and Ramanella variegata (0.281). Highest niche breadth was observed in Euphlyctis cyanophlyctis (0.228), while the lowest was observed in Ramanella variegata (0.000) indicating a high degree of specialization. This study indicates that the level of dietary niche overlap is low in the amphibian community studied here and hence, a high degree of dietary niche partitioning. The study also reveals a trend towards dietary specialization and possibly low level of competition for food in this amphibian community. The study also provides valuable insights into the dietary ecology of these amphibians, which will be invaluable for the formulation of conservation strategies for these species.
Impact of invasion of Cogon grass (Imperata cylindrica) on the physical and chemical properties of soil
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Bandara, M.S.P.M.; Dilshara, R.M.P.; Gunarathne, D.K.O.B.; Senevirathne, H.; Udayanthika, S.K.I.; Kumari, C.
Cogon grass (Imperata cylindrica) is an invasive species found in many parts of Sri Lanka. This species is among the top ten worst weeds in the world. Cogon grass is found on road sides, mining sites, abandoned plantations and many other areas with disturbed soil forming a dense field like monocultures. The objective of this study was to assess the impact of the invasion of Cogon grass on soil physical and chemical properties. The present study was conducted in a selected site at Nelumdeniya, a village located at Eastern part of Sabaragamuwa Province. Three sites were identified within the study area, of which two sites are invaded by Cogon grass with a high to low level of cover. The remaining site without the weed (undisturbed site) was used to assess the condition of soil before invasion of the weed in above sites. From each site five soil samples were extracted using a soil corer to analyze soil particles density, soil bulk density, porosity, moisture content, organic matter content, conductivity and Nitrogen content (kdjeldahl method) in soil. The moisture content of undisturbed site (0.78) was less than the two sites invaded by the Cogon grass (0.88 and 0.89). The organic matter content (OM) and the Nitrogen content of soil in undisturbed site (OM= 0.163%, N= 0.14%) was higher compared to the other two sites (OM= 0.083% and 0.107%; N= 0.13% and 0.11%). The bulk density and the porosity was higher in affected areas than the undisturbed site. The study reveals that the invasion of Cogon grass affects both the physical and chemical properties of soil.
Invasive potential of exotic ornamental fish species in Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Piyathissa, M.G.M.U.; Ranasinghe, S.D.A.E.; Ranasinghe, Y.G.; Rathnayaka, R.M.K.H.; Epa, U.P.K.
The accidental releases of fish species from ornamental fish industry have become one of the top five pathways for the introduction of invasive species in the world. These accidental releases of species in to new environments are more environmentally damaging in most instances compared to intentional introductions. Seven out of 12 invasive alien animal species found in Sri Lanka are fish species and majority of them have been introduced by ornamental fish trade. This study was conducted to assess the invasive potential of exotic aquarium fish species in Gampaha, Kandy and Polonnaruwa districts in Sri Lanka. Twenty aquarium hobbyists, three pet shops and three fish breeders in each district were randomly selected and fish species present in their captivity were identified. The invasion potential of species present was evaluated using their thermal tolerance, history of invasion elsewhere, and potential propagule pressure calculated by frequency of occurrence in homes, pet shops and breeding centers. Reasons for fish releases and biosecurity measures adopted by the industry were also recorded using a questionnaire survey. Overall 51 exotic ornamental fish species belong to 14 families Poeciliidae, Loricariidae, Characidae, Osteoglossidae, Cyprinidae, Osphronemidae, Helostomatidae, Cichlidae, Acanthuridae, Callichthyidae, Characidae, Cichlidae, Salmonidae, Scombridae were recorded during the study. Xiphophorus maculatus, Pterygoplichthys pardalis, Poecilia reticulate, Cyprinus carpio, Osphronemus goramy, Trichogaster trichopterus, Clarias batrachus, Pterophyllum scalare, Carrasius auratus, Danio rerio and X. helleri had high invasive potential while Osteoglossum bicirrhosum, Astronotus ocellatus, Astronotus sp., Puntius tetrazona and Betta splendens have moderate invasive potential in the country. Colossoma macropomum, Salmo trutta, Pethia conchonius, Gymnocorymbus ternetzi, Hemichromis bimaculatus and Acanthurus dussumieri showed low invasive potential. The reasons for releasing fish into natural environments were increasing body size, aggressive behavior, diseases, high reproduction rate, difficulty to maintain and due to unexpected floods. Fish breeders cover the ponds by a net to prevent fish escapes and to prevent predators as a biosecurity measure. Education, training and extension be used to inform general public and aquarium industrialist of invasiveness of fish species and their environmental impacts. Laws and regulations to prevent fish releases to natural environment should be introduced and implemented through intervention of the government.
Patterns and perceptions of wildlife crop raiding in and around the Kaludiyapokuna Forest Reserve in the dry zone of Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Perera, M.; Vandercone, R.
Expanding human population and rapid conversion of natural habitat to agricultural land has led to greater proximity between humans and wildlife. Crop-raiding is an outcome of both natural resources becoming less accessible and the nutritional benefits of cultivated foods becoming increasingly known to wildlife. The resulting financial losses suffered by farmers from crop raiding can be relatively high and is compounded by the lack of compensation for losses. Such a situation can make farming communities intolerant and unsympathetic towards wildlife and even coerce farmers to adopt drastic measures such as killing of problem species and hence impede conservation strategies. However, in order to mitigate this form of human–wildlife conflict, it is first necessary to understand the temporal nature of crop raiding by different animal species as it is fundamental towards developing cost effective guarding strategies. Data on perceived and actual crop raiding event was collected from July 2013-August 2014, from 36 farms around the Kaludiyapokuna Forest Reserve, Sri Lanka. Study respondents have identified Pavo cristatus (38%), Elephas maximus (27%), Semnopithecus priam (21%) and Macaca sinica (14%) as the most destructive crop pests. From 8012 crop raids by eight species of animals, most raids were indeed made by the Pavo cristatus (59%) and Semnopithecus priam (28%). The average monthly relative frequency of crop raiding was 0.07 (range 0.02-0.27). The highest monthly relative frequency was recorded in August. Only the monthly relative frequency of crop raiding by M. sinica was positively and statistically significantly correlated (p= 0.09) with monthly rainfall. When cropping systems were considered, 64% of the crop raiding incidents were recorded from monoculture farms, while only 36% were recorded from polyculture farms. Our study demonstrates that animals differ in their crop raiding behavior and also that certain species show temporal variation in crop raiding patterns. In addition, cropping systems also appear to be linked to crop raiding preferences of wildlife. Our study also provides a useful starting point for future studies investigating temporal and spatial factors predicting crop raiding by wildlife.
Comparison of Soil properties in three selected sites within the premises of University of Kelaniya, Dalugama, Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Dissanayaka, D.M.C.P.; Dissanayaka, C.T.M.; Weerathunga, D.M.; Wijesekara, N.T.A.; Perera, G.L.D.N.; Abeykoon, H.L.S.N.; Ranasingha, B.M.C.J.; Kanagasabai, S.
The soil physical and chemical properties largely determine the plant growth and it is a determinant of the composition of faunal communities. The objective of this study was to compare the soil physical and chemical properties in three selected sites within the premises of University of Kelaniya. The study was conducted in three selected sites within the University of Kelaniya; botanical garden, university ground and in a construction area. A total of three soil samples were extracted from each site using soil corer to analyze the soil moisture content, organic matter content, soil pH, soil surface temperature, bulk density, particles density and porosity. According to the results of present study the soil porosity is highest in botanical garden (81.6%) with relatively undisturbed soil whereas the soil moisture content and the organic matter content were highest in university ground (moisture content= 1.27; organic matter content= 6.27%). The construction site that subjected to severe disturbances due to heavy machinery usage, showed the highest bulk density (0.39 Mg/m3) and lowest porosity (78.7%) from all three sites. This study reveals that the soil properties within the university premises shows a considerable variation which can be explained with the degree of disturbance to the area.
Assessment of water eutrophication in selected locations of the Diyawanna Oya using chemical assessment methods
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Samarawicrama, L.D.R.; Sanjeevani, K.S.; Sammani, D.G.P.; Rathnayake, A.K.V.H.; Wijeyaratne, W.M.D.N.
Eutrophication is one of the most widespread environmental problems of inland water bodies of Sri Lanka. It has lot of negative impacts on the aquatic ecosystems including increased biomass, growth of harmful algal species, decrease in water transparency, changes in the biodiversity and effects on the aquatic food web. In addition, eutrophication can cause serious health effects in humans and domestic animals. Diyawanna oya is one of the major water body situated in Kotte area that is currently showing signs of eutrophication and many problems associated with it. The objectives of the case study were to compare BOD levels, COD levels, Chlorophyll a, and NO3- and PO43- levels in selected three sites of Diyawanna Oya with Sri Lankan water standards and to compare physical parameters such as Temperature, pH and Visibility in three selected sites over wet, dry and intermediate seasons. Three sites were selected for the study and, sites 1 and 2 were rehabilitated sites while site 3 was a non-rehabilitated site. BOD5 of the study sites ranged from 5.5-8.0 mg/L which is higher than the permissible threshold limit (>5 mg/L).The COD value of tree study sites during the period of case study was between 15.501- 41.670 mg/L, The nitrate concentrations of the three study sites varied between 1.3 – 2.5 mg/L during the period of study while the phosphate concentration varied between the values of 8.8 – 50 mg/L. Higher BOD values and Chlorophyll a were observed in sites 2 and 3 and higher values for COD and nitrate concentrations were observed in sites 1 and 2 meanwhile higher level of phosphate concentrations were observed in all three sites. Many of the readings obtained exceeded the highest permissible threshold limits that should be present in inland water bodies of Sri Lanka. Chlorophyll a level in the selected three study sites were in the range of 3.11 – 29.82 mg/L. The water temperature of the three study sites were between 310C – 340C and the pH ranged from 7.64 – 8.57 showing a slight alkaline conditions in the water of the study sites. Visibility was relatively low in all three selected study sites during the study period. According to the results it was noted that Eutrophication in Diyawanna oya cannot be monitored using only chemical assessment. Regular visual assessments accompanied with routinely chemical analysis of water quality can help in maintaining and keeping eutrophication of Diyawanna oya at controlled condition. By taking proper regulatory, control methods Diyawanna oya and the ecosystem that is bound with it can be protected.
E-Waste management in selected institutions in Colombo and Gampaha Districts
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Athukorala, S.M.W.; Handapangoda, H.M.A.K.; Yatawara, M.D.M.D.W.M.M.K.
Electrical and electronic waste (e-waste) is one of the most rapidly growing environmental problems in the world including Sri Lanka. This preliminary study was carried out to identify the attempts of e-waste management in selected institutions in Colombo and Gampaha districts. A questionnaire survey followed by interviews was carried out among randomly selected 20 institutions in Colombo and Gampaha districts. Descriptive statistical methods were used to analyze data. Results revealed that about 55% of respondents reuse their e-waste and 15% of respondents continue recycling the discarded e-waste. Most respondents (95%) has knowledge on e-waste and the effects of unsafe disposal. In addition, 60% of respondents were not aware of any projects or activities on e-waste management by government and local authorities. However, most of the types of electronic devices that are used by these institutions were more or less similar. Further, the survey revealed that the respondents showed willingness to contribute to e-waste management and willingness to pay or willingness to accept for a green product which will not harm the health of human and the environment. The study suggests to conduct proper awareness programmes to the employees in the institutions on handing over, disposal and management of e-waste. In addition, proper monitoring programmes of recycling or disposal is utmost important as e-waste contains a substantial amount of valuable recyclable materials and has potential to become a lucrative business in the country.
Arthropod diversity in four different ecosystems in the Mid Country Wet Zone of Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Weerathunga, W.A.M.T.; Athapaththu, A.M.G.K.; Amarasinghe, L.D.
Arthropods contribute significantly to biodiversity of natural environments. The present study was done to determine the diversity of arthropods in four ecosystems with different vegetation. Vegetation surrounding an aquatic environment (AQ), a broad-leaved wet, evergreen forest ecosystem (BL), a Pinus caribaea monoculture plantation (PN) and a Pinus plantation artificially enriched with indigenous broad-leaved tree species (PNEN) located close to each other in Peradeniya were selected. In each environment, arthropods were sampled in three randomly-selected sites (5m x 5m) using four sampling methods, namely, pit-fall traps, sticky traps, sweep net and beating tray. Collected arthropods were identified upto the highest possible taxa using standard identification keys, based on morphological characteristics. Simultaneously, a plant census was conducted. Arthropod- and vegetation diversities were computed separately for each site using Shannon-Wiener Index (H). A total of 324 arthropod individuals were collected from all four sites. (AQ–71, BL–44, PN–20, and PNEN–189).They belonged to 68 species and 43 families. A total of 4416 plants were observed, from 84 species and 42 families. AQ had the greatest arthropod diversity (H=2.642), dominated by Olios spp. (Family Sparassidae) followed by BL (H=2.444), dominated by three arthropods, namely, a tettigonid species, Oxytate spp. (Family Thomisidae), and Psechrus spp. (Family Psechridae). PN had the next highest arthropod diversity (H=1.411), dominated by Dicaldispa spp. (Family Chrysomelidae). The lowest arthropod diversity was found at PNEN (H=1.3500), dominated by a formicid species. In contrast when considering plant diversity, PNEN had the highest diversity (H=2.614) and PN the lowest (H=0.879). AQ (H=1.810) and BL (H=1.871) had intermediate values. The arthropod diversity of AQ and BL was not significant from each other, while AQ was significant from the other two (F=5.50, P=0.024). PN and PNEN were not significant from each other. It was observed that in AQ, BL and PN the arthropod diversity was linearly dependent on plant diversity (R2=0.423) whereas it was not so when PNEN was also included (R2=0.008). This shows that higher plant diversity contributes to greater arthropod diversity in ecosystems where human intervention is minimum. But this pattern was not visible in PNEN, which is an artificially-created ecosystem.
Moisture reduction in Municipal Solid Waste (MSW) by parabolic solar dish method
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Heshani, A.L.S.; Abeysinghe, A.M.M.S.M.; Handapangoda, H.M.A.K.
The moisture content of MSW in tropical countries is higher when compared with temperate countries due to the climate (hot and humid weather with abundant rainfalls), compositions and types of waste generated. The moisture adversely affects the waste to energy conversion process as the process consumes more energy to evaporate moisture from MSW. Therefore, waste to energy concept receives less attention in MSW treatments, especially in tropical region. However, reduction of moisture of MSW would be beneficial to convert waste into thermal energy effectively and efficiently. Use of solar energy is a widely-practiced strategy to reduce moisture content in many materials. In this concept, the present paper suggests a method to reduce moisture in MSW by utilizing solar energy. Objective of this study is Develop a Model for Moisture Reduction of MSW by using solar energy. The parabolic solar-energy concentration method is applied to convert solar energy into thermal energy. The method is used as a principle of solid waste moisture reduction instrument. Three major components can be identified in the instrument, namely shredder, parabolic dish and compacter. Purpose of shredder is to reduce the size of waste that enables the entry to parabolic center pipes. As well, it increases the surface region of waste to evaporate water vapor without difficulty. The parabolic dish consists with parabolic dish, solar radiation center with hot air fans and waste flow pipes. Concentrated solar energy is centralized by using parabolic dish. Then solar energy is converted into thermal energy when focus onto the counter and exhausted, hot air fan generate Dry Air flow with higher temperature, because of the properties of air flow, it reduces humidity and thereby decrease of moisture content is accelerated. Temperature of dry air flow in center level is higher than boiling point of water (T >100oC), and this high temperature conditions generated from concentrated direct solar energy to center level and heating element converts solar energy into heat through the process of Joule heating, flow passing through this heating element resulting in heating of the air. Contact time of air flow with waste stream depend on moisture reduction of waste. Also, the continuous solid waste stream is transferred through the pipes and speed of flow depends on the decrease rate of moisture content at a center level. Solar electrical energy is used to operate this instrument. This scheme is fully automated and electronic detectors are applied to measure temperature, moisture content. After reducing the moisture content in solid waste, it can be compressed and used to produce pellets. This resultant pellets can be used as fuel. Besides, it can be applied as ecofriendly bricks by mixing with strong solidified materials. In addition, no greenhouse gas emission is expected during the operation. Optimal instrument size depend on the Size of parabolic dish that displays quantity of solar energy concentrated to center point. As most of the industries have to spend a considerable amount of money on reducing the moisture content in the final disposal; especially in the Sri Lankan case, the waste generated is sent to a monopoly holder for further treatment. If industries can use this method as a preprocessing method to reduce moisture content in semi-solid or solid waste, it would reduce a significant cost. The proposed system is controlled according to a computerized system within specified limits. However, further development is needed to overcome bottlenecks and gaps in the system.
Assessment of water eutrophication in selected locations of the Diyawanna Oya using visual assessment method
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Samarawicrama, L.D.R.; Sanjeevani, K.S.; Sammani, D.G.P.; Rathnayake, A.K.V.H.; Wijeyaratne, W.M.D.N.
Diyawanna Oya is one of the precious assets in the Colombo metropolitan of Sri Lanka. Some parts of Diyawanna oya is currently under the threat of eutrophication due to rapid development and urbanization of the area. There is a large number of low income houses and several large scale apartment complexes in close proximity to Diyawanna oya. Quality of water and habitat in most of the areas is mainly influenced by public effluent discharges to the canal system, which has a significant environmental effects on the wetland. The objectives of the case study were to use the visual assessment method to compare the levels of eutrophication and to identify the perspectives of the local community on the eutrophication. Three sites were selected for the study and, sites 1 and 2 were rehabilitated sites while site 3 was a non-rehabilitated site. Replicate water samples were collected from each site to cover wet and dry seasons. In visual assessment, presence of Pheriphytons , Phytoplankton, Free floating aquatic plants, Rooted submerged plants, color and odor of water was ranked according to standard visual assessment criteria. Face to face interviews using a questionnaire were carried out by interviewing 40 individuals in the local community. Considerable amount of Pheriphytons, Phytoplankton, Free floating aquatic plants, Rooted submerged plants were observed in sites 1 and 2 while site 3 indicated an elevated level of phytoplankton. The community survey revealed the lack of knowledge of the respondents on eutrophication is the major cause for eutrophication associated problems. The results of the community survey revealed that, majority of the respondent population (74.6%) that lives close proximity to Diyawanna oya does not use the water that can be obtained from that water body for any commercial activity as a result of heavy water pollution, lack of cleanliness and hygiene , but few people (25.6%) uses water that can be obtained mainly for washing vehicles and for fishing activities During the survey it was noted that the residents of the area have frequently suffered from various skin diseases (especially during the rainy season) and vector borne diseases such as Dengue and Filariasis. Majority (59%) of the respondents were not aware of the animal kills associated with eutrophication and related problems. While (41%) expressed observation of fish and bird kills from time to time. The results of this case study shows that Diyawanna oya is heavily polluted with sewage, domestic organic waste and cleaning materials. The pollution is worsened due to over population, urbanization, decrepit infrastructure, inadequate cleaning programs and malfunctioning in the existing programs and also due to breaches in local government management system. The results of this study highlights the immediate control measures to overcome the environmental impacts of eutrophication in Diyawanna oya.
Effect of ammonia inhibition on anaerobic conversion process of pig manure
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Sandani, W.A.P.; Amarasekara, D.A.T.; Kodithuwakku, D.S.; Rathnasiria, P.G.
Anaerobic digestion process inhibits due to the presence of ammonia, sulfide, light metal ions (Na, K, Mg, Ca, and Al), heavy metals, and some organics (cholorophenols halogenated aliphatic, N-substituted aromatic, long chain fatty acid). Ammonia is the main inhibitory factor in pig manure as it contains nitrogen. Although it is an important buffer in the process and an essential nutrient for microorganisms, if not controlled, high concentrations causes to operational failures. It is also leading to a low methane yield. Since ammonia has free cell membrane-permeability, it is the active component causing ammonia inhibition. As ammonia is hydrophobic, the molecule diffuses passively into the cell which causes proton imbalance and potassium deficiency. Free ammonia concentration depends on the total ammonia (NH3 + NH4+), pH and temperature. Total ammonia concentrations level of around 1700–1800 mg/l, completely inhibitory to the inoculum which has not adapted. Literature shows that, with adaptation, inhibitory total ammonia nitrogen levels could increase up to 5000 mg/l. By using a semi continues anaerobic digestion process with an anaerobic inoculum and pig manure, can achieve that adapted inoculum. Adapted inoculum can give more than 250ml of bio gas volume per 50ml of pig manure which has 7% w/w solid content. Because of above phenomena methonogen bacteria can be completely inhibited while Acetogen bacteria still can produce acids in a toxic environment. Therefore, acids are formed leading to lower methane yield. Due to that reason, when pig manure is anaerobically digested with adapted inoculum, pH drops from 6.5 to 6.3 during first 3days. There are several methods mentioned in literature to reduce the ammonia inhibition directly in the anaerobic processes such as adaptation of microorganisms, co-digestion, increasing the COD:TKN (Chemical Oxygen Demand: Total Kjeldahl Nitrogen), dilution of the reactor content and adding trace elements. In this research Co digestion strategy was used to minimize ammonia accumulation in pig manure anaerobic digestion process. Pig manure was digested with food waste in different ratios. Adapted inoculum was used for this process.
Water audit in Yakkaduwa Pangnasara boy’s hostel, University of Kelaniya
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Mudannayaka, M.M.M.K.; Pathum, B.A.V.J.; Mathithipan, S.; Jeyasri, N.; Weerasinghe, V.P.A.
Water audit is a systematic approach of identifying, measuring, monitoring and reducing the water consumption by various activities in a building/institution/industry. This water audit was done for the Yakkaduwa Pangnasara hostel building in the University of Kelaniya. To achieve the main objective of water budget in the hostel building, there were sub objectives namely; identifying water uses, measuring actual water consumption, identifying water wastage and leakages and giving suggestions for water reduction of wastage and leakages carried out. Water usage volumes were identified using visual observations. Actual water consumption was estimated using a questionnaire survey and flow rate measurements. The questionnaire survey was based on the water usage data of students, non-academic and canteen staff. Visually observed leakages were measured. Using observations and flow rate measurements data, the actual consumption was estimated. Total input was calculated using water bills. Finally, the unaccounted water loss was calculated using total input and estimated consumption. The unaccounted water loss should be equal or less than 5% in well managed water system, but in this water audit the unaccounted water loss is 8.52 %. Unaccounted water losses should be reduced by decreasing water losses and applying more water conservation practices in the hostel. Awareness programs also will help to reduce the water losses in the hostel.
Determination of construction vibration & noise effect extent
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Meegaswatte, D.
With the Global Village concept contemporary mankind started to share technology, knowledge, strategies etc. among the nations. As a result of exposing to such innovative atmosphere people started to seek competitive development notwithstanding the economic category of them. Consequently development projects have become a basic need of a nation. This case study clearly based on a construction stage of Outer Circular Highway development project which was executed by government of Sri Lanka in collaboration with Japan International Cooperation Agency (JICA). This expressway runs 8.9 km from Kadawatha to Kaduwela and it is one of the phases of Outer Circular Highway to the city of Colombo. Construction works of this project was commenced on 09.01.2012 and the facility was opened for public on 17.09.2015. At the planning stage of this project, RDA recommended to identify and declare 50m corridor from the boundary of the project area to outside on both side of the road during the construction phase which is known as “Impact Area”. The main purpose of establishing such impact area was to avoid controversial social issues which arise due to property damages. Foremost cause of property damages is Vibration which derives from construction activities. Anyhow end of the project all houses, buildings which locate within this impact area were subjected to a damage evaluation process and properly compensated. Main objective of this case study is justification of allocation of 50m corridor as impact area because so far a rational explanation has not been provided to prove the adequacy of 50m width. In this study monitoring data which gathered during entire construction stage (three and half years) were used in order to build a correlation among vibration effect and the distance. During the construction stage a qualified team had been deployed for the monitoring purpose. Noise and Vibration levels were measured randomly and complain basis (once a complain received regarding excessive noise or vibration, the monitoring team visits particular location and performs monitoring). Each measurement was recorded with its corresponding offset (distance from the activity to monitoring location). Noise and vibration monitoring was carried out for 3 years in that manner. Entire monitoring data were filtered into each significant construction activity and arranged them monthly wise of each year. In the vibration level analysis of each construction activity, highest vibration level which was recorded during each month was plotted against the corresponding offset. Although same correlation was applied for noise level analysis, lowest noise level of each month was used apart from the highest record of each month. Since this study deals with two-dimensional variables a Trend Line is determined in order to identify the tendency of the trend. This developed trend line gives assistance to determine the adequacy of buffer zone allocation.
An assessment of the avifaunal diversity in Hapugastenne estate of Ratnapura District, Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Fernando, G.K.; Perera, S.J.
An avifaunal survey was conducted at Hapugastenne Tea Estate (1302ha), Ratnapura, Sri Lanka from November to December 2015 with objectives of assessing the bird diversity within different habitats and documenting threats to biodiversity. Bird populations were sampled in 39 line transects and 17 point counts for terrestrial and aquatic habitats respectively representing eight habitat strata (tea fields, home gardens, scrublands, secondary forests, natural forests, stream-side vegetation, riverine forests, and water-logged areas) within the estate, replicated in its nine divisions. Transects were conducted during the morning between 07:00 and 09:00 hrs. A total of 91 species, including nine Sri Lankan endemics and nine winter visitors were recorded, which included one globally and six nationally near threatened species. Estimates of relative abundance indicated a high degree of rarity, with only few abundant species, the red-vented bulbul being the most abundant. Among the habitats, the highest species richness (39) was recorded in stream-side vegetation where Simpson’s diversity index (0.947) was also the highest, while the Shannon-Wiener diversity index (H’=3.247) is marginally second to tea fields (H’=3.382), where the evenness was the highest (J=0.994). Interestingly, the Shannon-Wiener diversity and the evenness of the secondary forest fragments were comparable to those of home gardens (H’=2.591; J=0.795 and H’=2.515; J=0.791 respectively). The results of the feeding guild analysis indicated a greater abundance of the insectivore guild was greater in tea field than in other habitats. In contrast, the relative abundance of frugivore guild was higher in the natural and secondary forests. Cluster analysis indicated a highly dissimilar species composition in scrublands compared to other habitats, while tea fields and home gardens were very similar in their avifauna. The study revealed that this managed landscape provides a diversity of niches maintaining the natural biodiversity to a certain extent. Nevertheless, 14 alien invasive species (nine plants and five animals) were identified from the area among several other threats to the biodiversity. Increasing plant diversity, introduction of shade trees and connecting remnant natural habitat patches via stream reservations are recommended to conserve and enhance the avifaunal diversity in the study area.