How do Sri Lankan shrub frogs Philautus popularis spend their night time: Field observations from Bolgoda wetland complex
By lakmali | March 17, 2010
H.G.S.K. Dayananda and D.D. Wickramasinghe
Sri Lanka is an amphibian hot spot providing home for 109 species. Nevertheless, studies on ecology and biology of amphibians of Sri Lanka are scarce and behaviour of frogs has drawn even less attention. Philautus popularis (Ranidae, Rhacophorinae; Manamendra-Arachchi & Pethiyagoda, 2005) is an endemic shrub frog which occurs in the low country wet zone. This study attempts to report behaiourl
spectrum of P. popularis in an undisturbed wetland in an urban area. Study site comprised of two locations in Bolgoda south lake wetland complex (790 52’ - 790 59’ north longitude and 060 42’ - 060
51’ east latitude).
This study was carried out for one months starting from mid June 2009 from 1800 hrs onwards. On each study date, a random path was chosen to walk till a frog was found. The observations were made according to focal animal sampling method, by the naked eye. When an animal was found the total behavioural pattern was studied carefully from a point 1 m away from the frog. Times spent on different
behavioural activities were noted. A total of 64617 seconds (nearly 18 hours) were spent on different
behavioural activities.
Twenty nine individuals (26 males and 3 females) were studied and seven behavioural events were encountered: acoustic, locomotion, resting (No movements), foraging, agonistic, cleaning and sexual behaviour. Time taken for each behaviour was compiled taking both sexes into consideration. The most
abundant behaviour event was resting without any movement (45% of the total time) but sometimes
they showed feeding in between. When activities are considered, they were found spending more time
for calling (27.1%, males only) and sexual behavior including amplexus (25%). Interestingly, agonistic
behaviour was shown by males and time taken was 2.1% of total. Walking, cleaning, jumping and climbing took a negligible proportion of the total time and were less than 0.2 percent. Calling was observed from 1800-2300 and they were silent from 0130-0530 and then started acoustic signals again.
Perch height of males varied from 40-160 cm from the ground and the highest point was reached around
midnight. Females were always near the ground (5-15cm). Males are territorial and it is likely that their
home range is within a 5m radius.
This shrub frog used minimum time to climbing locomotion pattern and then jumping. The most abundant locomotion pattern was walking, spent 59.6% from the total time for locomotion to the walking. 3 Different perched postures were recorded and climbing position was recorded. Perched height and time has significant relationship respect to both study sites. There is no any preferred plant species for Philautus popularis. They spent 1380 seconds on agonistic behaviour, 2% of the total behavioural observation time. They spent time of 16,200 seconds in amplexing. They hide under leaf litter during
day time.
H.G.S.K. Dayananda and D.D. Wickramasinghe
Department of Zoology, University of Colombo, Sri Lanka.
Topics: Biodiversity, sympoisum 2009 | 2 Comments »
Distribution and population parameters of selected tree species in Gilimale and Kithulgala Forest Reserve
By lakmali | March 17, 2010
S. S. Ranathunga and B.M.P Singhakumara
Field surveys have not been carried out in Sri Lanka to gather the population data on critically endangered tree species in their habitats. The population data on the critically endangered tree species are important to understand the present status of the population. In this study, the population data of seven critically endangered tree species were gathered.
Habitat distribution and some population parameters such as stand tables, plant community composition and structure were studied for seven Critically Endangered (CR) tree species found in the Kitulgala and Gilimale Forest Reserves, tropical lowland rainforests in the southwest part of the country. The selected species are Stemonoporus gracilis, S. petiolaris, and Balanocarpus kithulgallensis in Kitulgala and Stemonoporus gilimalensis, S. lancifolius, S. scalarinervis, and Memecylon macrocapum in Gilimale. Balanocarpus and Stemonoporus an endemic genus belong to the family Dipterocarpaceae and
Memecylon macrocapum belongs to the Melastomataceae.
Sampling of vegetation has been carried out in specific habitats for each selected Critically Endangered species. Suitable plots were identified by a reconnaissance survey and 100×5 m plots were demarcated. All the plants below 1 m of height were counted as seedlings; all the plants less than 2 cm of dbh and over 1 m of height were counted as saplings. DBH and heights of trees over 2 cm dbh were measured.
Survey data of the selected tree species are used to calculate the Important Value Index (IVI). Profile
diagrams were prepared for each tree species to show the vertical distribution in their habitats. Distribution maps of these species were prepared using digital data. Sample plots are located in 1: 10,000 digitized maps prepared by the Survey Department, Sri Lanka.
All species show patchy distribution and these patches are found in different parts of the forest topography. Stemonoporus gracilis, S. petiolaris, S. gilimalensis, S. lancifolius and S. scalarinervis show positive stand tables with reverse “J” distribution curves. This indicates that these populations in their habitats are healthy. Balanocarpus kithulgallensis and Memecylon macrocapum are not showing this type of curves, and more sampling has to be carried out to investigate the population structure of these two species.
All these species could be conserved by protecting their natural habitats (in-situ conservation) and only a two species (Balanocarpus kithulgallensis and Memecylon macrocapum) might need both in-situ and ex-situ conservation strategies.
S. S. Ranathunga and B.M.P Singhakumara
Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka.
Topics: Biodiversity, sympoisum 2009 | No Comments »
Utilization of treated tannery waste water using HRTS (High Rate Transpiration System)
By lakmali | March 17, 2010
S. Krishnamoorthi and G. Kandasamy
The major objective of this paper is given to soil and ground water quality improvement by utilizing the high transpiration pull property of specific plants. It acts as a catalyst to improve the water management and also effluent is getting treated in a eco friendly manner. We utilized the tannery effluent for the High Rate Transpiration System (HRTS). The treated tannery effluent is distributed in the designed plants of ridges and Furrows. And three design layouts were developed in the research activity for the plantation to get Maximum benefits depends upon the load and the nature of effluent.
Moreover, implemented system results were collected and analyzed for the impact of system on the environment. The effluent loading capacity to the designed plants were calculated and summarized.
The advantages of the HRTS are 1) No separate processing is required for effluent 2) Effluent Solids will be taken as nutrient for the plants growth 3) Water in the effluent will be penetrated under the beneath of earth and improve the ground water quality as well as quantity 4) HRTS process is ecofriendly.
S. Krishnamoorthi and G. Kandasamy
Environmental Research Center, Sri Ramanathan Engineering College, Erode, India
Topics: Resource Management, sympoisum 2009 | No Comments »
Efficient removal of nitrogen/phosphorus by Bio-Geo Filter ditches consisting of laterite
By lakmali | March 17, 2010
G.S.M Fonseka1, N.P.M Rajaguru2, K.C.J Jayasekara2, B.C Liyanage2 and S.S. Iqbal2
In order to develop low-cost energy saving ways to treat wastewater in combination with resource recycling, a plant bed filter ditch in which terrestrial and aquatic plants are used to remove nitrogen (N) and phosphorus (P) from domestic wastewater specially from the septic tank effluents. Discharging waste water into inland surface waters leads to contamination of water bodies is becoming a serious problem in Sri Lanka. Though there are several treatment methodologies adopted to treat wastewater, a low cost system with less maintenance is very much needed that suits small waste capacities and for domestic installation, so as to prevent release of nutrients to the natural ecosystem. Therefore this study focuses on introducing an ideal treatment system using a combination of bio and geo materials namely Geo Filter (BGF) ditches.
A pilot scale Bio-Geo Filter ditches has been established at the Open University premises to demonstrate the potential for treatment of domestic wastewater using geo materials and plants. Selected bed filter materials and useful terrestrial plant species such as African merigold, canas, papyrus and reeds were employed for nutrient removal. This pilot-scale BGF containing laterite (kabook) stones with its rich composition of iron and aluminium, has been achieved nearly 100% removal of phosphorus.
The BGF shows the excellent pollutant removal efficiencies for NH4 +, NO3-, and NO2 -. Though the removal efficiency of NH4 + is 90%, while the removal of NO3 - and NO2- is around 100%. Ditches with papyrus and reed help to control pH before discharge. Reduction of turbidity and COD is also more than 90%. The BGF significantly removes TDS, conductivity and salinity. The plant species, which provides economic and aesthetically appealing aspects, will engage to produce renewable energy in further step of this study.
[This project was funded by the Asian Development Bank, Distance Education Modernization Project]
G.S.M Fonseka1, N.P.M Rajaguru2, K.C.J Jayasekara2, B.C Liyanage2 and S.S. Iqbal2
1Department of Chemistry, University of Colombo, Sri Lanka 2Department of Civil Engineering, Open University of Sri Lanka.
Topics: Resource Management, sympoisum 2009 | No Comments »
A Multi agent system for environmental friendly agriculture
By lakmali | March 17, 2010
R. Rupasinghe, A. Ranatunga, S. Rathnayake, A. Sajagahan and A. Karunananda
Environmental sustainability has become an important topic nowadays due to various adverse effects of natural systems which has caused the mankind to suffer in multi faceted difficulties. Achieving the environmental sustainability is not an individual effort but a collective effort of all the stake holders of a natural system. Therefore mankind should be able to work in harmony with natural processes in utilizing the environment without harming the sustainability.
Agriculture is a direct encounter of humans with the natural environment. Here, the challenge is to reap the maximum possible harvest in the most efficient manner while keeping up with the environmental sustainability. In addressing this issue we propose to incorporate modern agent technology for controlling an agricultural environment. Since we need a controlled environment we decided to select hydroponics, the technology of growing plants on a nutrient solution that supply all nutrient elements needed for optimum plant growth, in a greenhouse environment. We have built an adaptable hydroponics system with high level of autonomy with the help of a multi agent system. In doing so, we have combined embedded computer technology with the state of the art artificial intelligence. The system has a higher capacity of autonomous decision making in a dynamic environment. Decisions about activities to be performed by the actuators (dosing system, water control system etc.) were generated as an emergent property of interacting autonomous software components. Each of these software components represent a particular environmental parameter (nutrient level, pH level, temperature etc.) that is subjected to change dynamically. Each of these autonomous software components contains limited logical capabilities for interacting with nearby components in case of a change of the interested parameter. Therefore the decision will be emerge as a result of the interactions among individual software components with limited rationality. The advantage of this approach is that it enables the hydroponics system to become proactive to the environmental changes rather than being just a reactive entity.
The system has been evaluated using a domestic hydroponics environment. Firstly, we changed key parameters of the nutrient solution in an artificial manner to test how the system would react to those changes. For example, in the first scenario we reduce the water level and switch on the system. System was able to identify that and pumped the water up to the required level. Similar tests were conducted to ensure component testing. So we reduce the light, change EC / pH, change nutrient level. Also the system was evaluated through a comparative approach with the traditional agriculture. Five farmerswere utilized to obtain data about 6 six parameters for a period of 3 months. The test results showed a considerable improvement over the traditional agricultural practices. Therefore this research has shown that we could achieve a better harmony and sustainability with the natural environment by using the multi agent technology for controlling an agricultural environment.
R. Rupasinghe, A. Ranatunga, S. Rathnayake, A. Sajagahan and A. Karunananda
Faculty of Information Technology, University of Moratuwa, Sri Lanka.
Topics: Resource Management, sympoisum 2009 | No Comments »
Baseline Survey on Biodiversity in up country tea estates in Sri Lanka
By lakmali | March 17, 2010
G.G.T. Chandrathilake1
Conventional tea plantation was assessed in terms of biodiversity in up country tea estates in Sri Lanka. A rapid survey was carried out to document the both faunal and floral diversity associated in selected nine (9) tea estate in Nuwara Eliya district an areas that have not been properly surveyed for biodiversity. Based on vegetation types, physical conditions and edaphic factors, a total of five (5) major habitat types were identified as well managed tea fields, home gardens, forest/fuel wood plantations, abandoned land surface water bodies. All of the land cover is of anthropogenic origin while riparian vegetation (secondary) diminutive beside the numerous streams which originating from summits and flowing along steep valleys. Study started from August to October 2007 and direct observations, indirect observations and reliable information from local people were used to study birds, butterflies and mammals nested within the tea estate ecosystem while direct observation was used to record flora (except ornamental plants and vegetables) in representative habitats.
A total of 73 faunal species were recorded from study areas out of them 41 species of birds, 11 species of mammals, 16 species of butterflies 2 species of fresh water crabs and 3 species of fresh water fish. The birds identified includes seven endemic species (Sri Lanka yellow fronted barbet, dull blue flycatcher, Sri Lanka wood pigeon, Sri Lanka Jungle fowl, crimson-backed flame back, brown capped babbler and Ceylon white eye). Ceylon white eye can be seen in considerable abundance. Among the mammals presented Sri Lanka toque monkey was the endemic species while other nine species native to the Sri Lanka. All the butterflies recorded from the study area are under common and very common categories. The flora recorded from the survey area includes 108 species belonging to 45 families. Most of the trees are introduced planted species while most of herbaceous species encountered are considered as weeds (46). These include 42 species of trees and remaining 62 species of woody shrubs, herbs, grass and 4 species of ferns.
Conventional agricultural practices like application of pesticide, weedicieds and inorganic fertilizer, land degradation due to soil erosion and spread of invasive alien plants were observed as common threats to existing taxa. Introduction of organic tea farming, Agroforestry systems and establishment of riparian vegetation along the surface water bodies will be important factors to the existing and to enhance the faunal diversity within the tea estate ecosystem.
G.G.T. Chandrathilake
1Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka.
Topics: Biodiversity, sympoisum 2009 | No Comments »
Efficiency of some local plants as eco-friendly pest control agents in reducing infestation
By lakmali | March 17, 2010
T.V.N.M. Gunarathna and M.M.S.C. Karunaratne
Repellent effects of powdered leaf mixtures of four plant species, Piper nigrum (black pepper), Ocimum gratissimum (maha maduruthala), Cinnamomum verum (cinnamon) and Mentha viridis (mint) were evaluated against the adult rice weevil, Sitophilus oryzae under laboratory conditions (29 ±200 C and 84±2 % relative humidity). The evaluation was made with the view of finding plant materials that effectively protect stored produce and are less poisonous and less detrimental to the environment. A modified cup-bioassay was used for repellency tests. Leaf powders of the plants were tested separately and in different mixtures against S. oryzae. Four combinations of leaf powders were made using two plants at a time (15g altogether) at 1:1 ratio, and added to hundred grams of clean and un-infested rice grains separately. Similarly, another bioassay was set by mixing powdered leaves of all four plants together at a ratio of 1:1. Twenty rice weevils each were introduced into bioassay chambers. When compared with the control, all combinations of plant leaves caused significantly higher repellency (p < 0.05) in adult weevils. Repellent effect of the mixture of M. viridis and O. gratissimum was the most striking as it elicited an extremely high repellency (95.0%) in the weevils just after 2 hours of exposure. Conversely, the weevils demonstrated considerably high rates of repellency to the combinations of, P. nigrum + M. viridis, and P. nigrum + O. gratissimum which were 88.0% and 87.0% respectively. In contrast, a significantly low rate of weevil repellency (46.0%) was observed with the combination of C. verum and P. nigrum after 2 hours. Moreover, a very much high repellent activity (85.0%) was also obtained when weevils were exposed to the combination of leaf powders of all four plants mixed together. Furthermore, when tested separately, only M. viridis elicited a high repellent activity (90.0%) in the weevils. Also, the highest rate of repellency with single plants was observed only after 6 hours of exposure where as all the plant combinations showed their highest repellent effects shortly after 2 hours of exposure. These observations clearly indicate a rapid and great increase in weevil repellency when different mixtures of plant powders were used. The results of the present investigation highly signify the potential of using mixtures of the four plant materials, especially the combination of M. viridis and O. gratissimum as eco-friendly pest control agents in reducing infestation of rice caused by S. oryzae.
T.V.N.M. Gunarathna and M.M.S.C. Karunaratne
Department of Zoology, University of Sri Jayewardenepura, Sri Lanka.
Topics: Resource Management, sympoisum 2009 | No Comments »
Use of anti- fungal properties of clove, cinnamon, nutmeg and beetle leaf extracts to
By lakmali | March 17, 2010
P. Alahakoon, K.C. Madushani, N.H Jayawardana and R. Munasingha
An experiment was conducted to study the fungi associated with the anthracnose disease of Capsicum spp. in different locations and evaluating the biological control method compared to the chemical control method. The pathogenic fungi isolated were Colletotrichum gloeosporiodes, Colletotrichum capsici, and Colletotrichum coccoides. Pathogencity of fungi was confirmed and the symptoms were regenerated. Out of sixty nine disease samples, most common anthracnose fungus was Colletotrichum gloeosporioides. Therefore it was selected for further studies on evaluating the control methods. The treatments consisted of a control and six plant extracts. The efficacy of leaf extract, Cinnamomon zeylanicum (Cinnamon), Syzygium aromaticum (Clove), Miristica fragrance (Nutmeg), Piper betel (Beetle) and Piper longum (Tippili) in suppressing the growth of Colletotrichum gloeosporioides were evaluated in-vitro. Cinnamon and clove leaf extracts showed the highest reduction of growth of C. gloeosporioides whereas the nutmeg and beetle leaf extracts had moderate effect. The tippili leaf extract stimulate the fungal growth.The experiment was conducted using cinnamon, clove and nutmeg leaf extracts compared with two recommended fungicides chlorothalonil (contact) and carbendazim (systemic) to control anthracnose fungus in-vitro. Cinnamon, Clove leaf extracts and chlorothalonil, carbendazim showed the highest reduction of growth of C. gloeosporioides whereas the nutmeg leaf extract had shown moderate reduction of growth. The field trials also being conducted revealed that the anthracnose of Capsicum spp can be controlled by using clove and cinnamon leaf extracts also effective as the recommended fungicides. The plant extracts do not produced health hazard to human, low cost and environment friendly. Therefore plant extracts specially cinnamon and clove leaf extracts can be successfully applied to control anthracnose disease of Capsicum species.
P. Alahakoon, K.C. Madushani, N.H Jayawardana and R. Munasingha
Fruit Crop Research and Development Centre, Department of Agriculture, Sri Lanka.
Topics: sympoisum 2009 | 1 Comment »
Effects of carbofuran on survival and growth of Duttaphrynus melanostictus tadpoles
By lakmali | March 4, 2010
M.R. Wijesinghe, B.A.D.M.C. Jayatillake and W.D. Ratnasooriya
This study investigated the impact of a commonly used carbamate pesticide, carbofuran, on survival, growth, development and activity of larvae of the Asian Common Toad, Duttaphrynus melanostictus Schneider 1999. Continuous exposure trials of 15 days were conducted using tadpoles of Gosner stages 24-25 with a commercial grade carbofuran (Curaterr 3G). Four concentrations 50, 150, 250 and 500 μgl-1 were tested and treatments and controls (without pesticides) were maintained in triplicate (n=56 per treatment or control). Results revealed that there were marked elevations in mortality in larvae exposed to all tested concentrations as compared to those in the controls. Mortality was, however, not dose-dependent, but depicted a hermetic response, where mortality at 500 μgl-1 (35 %) was much lower than that recorded at 250 μgl-1 (62 %). The 15day LC50 value of D. melanostictus larvae was 190 μgl- 1. In contrast to mortality, the effects on growth, development and activity although pronounced, were transient. For instance growth impairments were noted until day 7, but the body size of surviving tadpoles were comparable to those in the controls by the end of the trial. Exposure to carbofuran to concentrations of 150 μgl-1 and above also caused several notable morphological aberrations such as swollen heads and thin tails. In particular, the fact that carbofuran induced high levels of mortality at the tested concentrations, which are below the field application levels, suggest that this pesticide may be detrimental to the survival of amphibians inhabiting agricultural landscapes in Sri Lanka.
M.R. Wijesinghe, B.A.D.M.C. Jayatillake and W.D. Ratnasooriya
Department of Zoology, University of Colombo, Sri Lanka.
Topics: Biodiversity, sympoisum 2009 | No Comments »
Diversity and microhabitats of termites in a natural and a secondary forest in Hantane hills, Kandy District
By lakmali | March 4, 2010
I.I. Hemachandra, 1,2, J.P. Edirisinghe 1, W.A.I.P. Karunaratne 1, C.V.S. Gunatilleke3
Termites (Isoptera) are the most important decomposers in tropical rain forests and are vital in maintaining nitrogen and carbon cycles. They are sensitive to disturbances, especially to forest canopy losses and hence are one of the important bioindicator taxa. The documented termite fauna of Sri Lanka is represented by 58 species in 28 genera. Research studies on termites of forests are few in Sri Lanka. Objective of this study was to determine the species composition, diversity and microhabitats of termites in a selected natural and a secondary forest in the Hantane hills.
The Hantane range is a series of hills, about 432 ha with an elevation between 518-1110 m. During the British period Hantane land was opened up for coffee, tea and rubber plantations. The selected study sites included patches of natural forest at > 1000 m elevation and a secondary forest, comprising mixed species, at elevations between 700-1000 m. A belt transect (2×100 m) was laid in each site for sampling termites. Each transect was divided into 20 (2×5m) sections and each section was sampled by 2 persons for 30 min. The number of encounters with termites (hits) of a given species within a transect was taken as the relative abundance of that species within that transect. An encounter is the presence of a species in one transect section (5×2 m). Termite diversity was compared using Shannon Diversity Index. Termites were also collected randomly from several areas within the two forest types for species determination.
A total of 11 termite species were collected from the two forest types using both methods. They are: from the natural forest Ceylonitermellus hantanae (Holmgren) (soil-wood interface feeder), Dicuspiditermes incola (Wasmann) (soil feeder); and from the secondary forest Odontotermes ceylonicus (Wasmann), O. globicola (Wasmann), O. horni (Wasmann) (all fungus growers and feeders), Nasutitermes fletcheri (Holmgren & Holmgern) (soil-wood interface feeder) and 5 unidentified species of Odontotermes Holmgren ( fungus growers and feeders) . A lower species Diversity Index was obtained for natural forest (H’= 0.683) compared to secondary forest (H’=1.630). The composition of termites species showed a marked contrast with none of the species in the natural forest being represented in the secondary forest and vice versa. The most common species in the natural forest was the endemic C. hantanae and in the secondary forest, the unidentified Odontotermes sp. 2.
A significant observation in both forests was the absence of termite mounds as well as long runways along live trees that lead to arboreal nests. The two termite species recorded from natural forest are subterranean nest builders that inhabit soil. The termites of the secondary forest inhabit soil, leaf-litter and wooden material like, tree stumps, logs, fallen branches and twigs. Termites of the fungus growing genus Odontotermes was confined to the lower altitudes.
A distinct difference in termite species composition, diversity and microhabitats was recorded from the two forest types, suggesting that altitude and temperature, among other factors may be influential environmental variables for termites.
I.I. Hemachandra, 1,2, J.P. Edirisinghe 1, W.A.I.P. Karunaratne 1, C.V.S. Gunatilleke3
1Department of Zoology, Faculty of Science, University of Peradeniya, Sri Lanka2Postgraduate Institute of Science, University of Peradeniya, Sri Lanka3 Department of Botany, Faculty of Science, University of Peradeniya, Sri Lanka.
Topics: Biodiversity, sympoisum 2009 | No Comments »