FOS Research Cradle Ep 02 | Charuni Pathmeswaran


Fourth-year undergraduate research is a topic familiar to some of us while it remains completely new to some other group of students. Therefore, with the purpose of increasing your awareness of the research, we at FOS Media thought of bringing you this series of articles on the Fourth Year Undergraduate Research done by our own brilliant alumni. This is the next step of the above-stated activity.

Our speaker today is Miss. Charuni Pathmeswaran was an Environment Science (Hons.) student in the Department of Zoology and Environment Sciences. She was born on 4th April 1991 and she is 29 years old now. She is the only child in her family and has completed her school education at Bishop’s College, she had entered the Faculty of Science, the University of Colombo to do her degree in the stream of Biological sciences. As for extra-curricular activities, she had involved in playing tennis and debating and she was also an active member of Gavel UoC and FOS Media Students’ Blog. Currently, she is pursuing a Ph.D. in heatwaves at the Climate Change Research Centre, University of New South Wales in Australia.

For the fourth-year research project, Miss. Pathmeswaran had the willingness to study the impacts of climate change. “Climate Change is a timely and relevant topic and I was interested in understanding more about its impacts. I was aware that Prof. Erandathie Lokupitiya had done a significant amount of research on climate change and I thought it would be good to carry out my research project under the guidance of such an experienced scientist”, says Miss. Pathmeswaran.

Accordingly, under the supervision of Prof. Erandathie Lokupitiya from the Department of Zoology and Environment Sciences, University of Colombo, she could conduct her research on the topic “Impact of extreme weather events on coconut productivity in selected locations in Sri Lanka.” Upon the completion of her thesis, she published the research in the European Journal of Agronomy. “As this was published while I was doing my Master’s at Bristol University, I was invited to deliver a seminar at the monthly Bristol Research Initiative for the Dynamic Global Environment (BRIDGE) meeting. Previously I presented the findings at the International Conference on Climate Change in 2017 held in Colombo. I also got the opportunity to present my findings at a climate adaptation meeting in Dhaka in 2018”, Miss. Pathmeswaran recalled the opportunities brought forth by this publication.

In this study, she had done a statistical analysis to study how extreme weather events such as high rainfall and high temperature impact coconut productivity in the Gampaha, Kurunegala, and Puttalam districts in Sri Lanka where she had spent nearly nine months on this. According to her, this study reinforces the importance of raising awareness of the implications of climate change on crop productivity. During her visits to the coconut plantations, the superintendents of the estates as well as the laborers appeared to be aware of the warming trend of the climate. They had adopted soil moisture conservation methods such as mulching, burying coconut husks, and growing cover crops to prevent extreme evapotranspiration. These can be considered short-term solutions. According to Miss. Pathmeswaran, if we are to think about sustaining coconut cultivation in the long term, it is important to focus our efforts on developing drought-tolerant hybrids. Global climate is projected to change continuously due to various natural and anthropogenic reasons. Policymakers and market decision makers can utilize the knowledge on how coconuts respond to drought conditions to formulate better policies and prices. This information can enable us to be better prepared and minimize loss and damage caused by a drought resulting from climate change.

She also had a second supervisor, Dr. Pramuditha Waidyarathne, a senior biometrician at the Coconut Research Institute. Under her guidance, she had been able to extract coconut productivity (number of coconuts per bearing palm) data from their coconut plantations. She had organized field visits to six plantations and she had been accompanied by her supervisors for these visits. Those field activities had given them the opportunity to interact with the superintendents and laborers with whom they had the chance to discuss the impacts of climate change on their plantations. They had also collected some soil samples during these visits which Miss. Pathmeswaran then could analyze in the lab of the Department of Zoology and Environment Sciences. She had carried out the statistical analysis using the statistical software Minitab.

Being more informative on her research, she said, “Our study analyzed the impact of extreme weather events considering daily temperature and rainfall over a 21-year period (between 1995 and 2015) at selected coconut estates in the wet, dry and intermediate zones of Sri Lanka.” Accordingly, six locations had been considered, such that two from each climatic zone (wet, intermediate, and dry) to prepare a comprehensive data set in the period of 1995-2015. The selected locations are as follows:

  • Dry Zone- Ambakelle, Thammanna
  • Wet Zone- Mahayaya, Walpita
  • Intermediate Zone- Rathmalagara, Hiriyala

Then, model relationships had been derived among high-temperature days, high rainfall days, low rainfall days as well as with mean rainfall and mean Tmax. Stepwise regression (Minitab Version 17.0 and SPSS Version 20.0) could be done and the Coconut productivity of a particular month had been analyzed against the meteorological data of the first four months after flowering.

Fig.01- Development stages of a coconut bunch (Source: Coconut Research Institute, Sri Lanka)

Then, the predictive power of the models had been evaluated through cross-validation by intentionally making some observed values missing and then filling them in using the models. The predicted values had been plotted against the observed values and an X=Y trend line could be constructed.

Cross-validation of models

predicted vs observed in dry zone
Fig.02- Graph of predicted vs observed values in the dry zone


predicted vs observed in intermediate zone
Fig.03- Graph of predicted vs observed values in the intermediate zone
predicted vs observed in wet zone
Fig.04- Graph of predicted vs observed in the wet zone

Soil parameters such as soil moisture content, soil pH, soil electrical conductivity, soil color, and soil texture of the six locations had also been measured. A statistically significant relationship could be found between the number of extreme weather events during the first four months after flowering and coconut productivity, in the dry and intermediate zones. The results also confirmed the consistency, comparability, and representativeness (of the zone) based on the soil parameters of the two sites within each climatic zone.

This study revealed some important findings. They are as follows:

  • The drought conditions during the first four months after inflorescence opening, had a negative impact on the coconut harvest in the dry and intermediate zones (as revealed by the statistical analyses and the model relationships developed in this study). Possible reasons for this include reduced pollen production due to the exposure of male flowers to elevated temperature (Burke, Velten, & Oliver, 2004) and flower and fruit abortions caused by high temperatures and absence of rainfall over an extended period of time (Nainanayake et al., 2008).
  • Drought conditions not only disrupt the physiological functions of the coconut palm but also contribute to incidences of pest attacks. At present, the Coconut Black Beetle and the Coconut Red Weevil pose the greatest threat to coconut plantations in Sri Lanka. Drought conditions are very conducive for Coconut Black Beetles to pupate deep in the soil (Nirula, 1955).

Miss. Pathmeswaran states that the model relationships derived from this study can be used to predict bimonthly coconut productivity up to 6-7 months in the future. Also, she mentions that one of the biggest challenges in carrying out this study was the lack of well-documented and digitized data relevant for research.

According to Miss.Pathmeswaran, if not for the help received by some personalities, she could not have accomplished this much success in her research. She extends her sincere gratitude to Prof. Erandathie Lokupitiya for her constant guidance and support given to her throughout the project, Dr. Pramuditha Waidyarathne from Coconut Research Institute for her guidance, Dr. Ravindra Lokupitiya for helping out with the subsequent analysis for her publication, and the Department of Zoology and Environment Sciences of the University of Colombo for all the support extended at all times.

Undoubtedly, this research has revealed some significant factors concerning the effect of climate change on the coconut which is one of the main export crops of Sri Lanka. These findings will be extremely important to uplift the productivity of coconut plantations which may have a positive impact on the economy of our country.

Scientists are often guided by the uncommon observations they encounter and the continuous research on them enables them to reveal the mysteries of nature as well as to give solutions to problems of the general public which need scientific explanations. Maybe, your undergraduate research would be a masterpiece that directs the world into a different path. Therefore, keep up your hopes and look forward to our next episode in this article series.


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