Invasion Biology the Field for Cum Laude Master’s Graduate

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Interaction between native and alien invasive aquatic snails was the thesis subject of Master of Science student, Ms Jacqueline Raw, who graduated cum laude in the field of Invasion Biology.  

Her research adopted an experimental approach to measure the behavior of the snails as they responded to chemical cues released naturally into their environment. 

The experiment was repeated using five native snail species at different localities within the iSimangaliso Wetland Park as well as in the laboratory at the School of Life Sciences on the Westville campus with the goal being to determine whether native snails had a specific or different response to the alien invasive species, Tarebia granifera.   

The study found that native snails actively moved away from the chemical cues of the alien invasive species thus establishing important ecological implications which potentially explains the success of T. granifera as an invasive species. The native snails are displaced from their habitat once T. granifera becomes established and this allows the invasive species to have access to more food and space resources. 

Professor Renzo Perissinotto said: ‘The novel study undertaken by Jacqueline Raw during her MSc investigated the role of interactions driven by chemical cues between aquatic gastropods, as a factor influencing the spread of alien invasive species such as Tarebia granifera, at an alarming rate throughout the coastal region of KwaZulu-Natal.  

‘This was a continuation of her earlier work carried out in 2012 during her Honours year. The results obtained in this latest study are important as they confirm earlier suggestions that in aquatic systems alien species are using chemical cues to enhance their invasion success, thereby displacing native species from their ranges. As usual, Jacqueline completed the study with great diligence and attention to detail, producing a manuscript of primary literature standards which is now under review in the prestigious journal PLoS ONE,’ said Perissinotto.  

Said Raw: ‘I was motivated to pursue a Masters degree in biology because I have a passion for the natural world. The fields of biology and ecology continuously provide answers to the intriguing curiosities of the world which we live in. Obtaining the Master's degree allowed me to carry out research based on observations of what is happening in ecosystems at present. Working towards the Masters degree required a lot of commitment and the experience was rewarding when everything was pulled together.’   

Raw felt one of the most important roles of a biologist in South Africa was  providing useful information about the natural environment which can be used to make informed decisions regarding the management of protected areas, the development of land for agriculture or industry and the regulation of activities which impact the environment.  

‘Biologists also play an important role assessing issues such as sea level rise and setting quotas for sustainable harvesting of natural resources.’  

Raw is currently registered at the Nelson Mandela Metropolitan University in Port Elizabeth for a PhD in Zoology. She is working under the Department of Science and Technology/National Research Foundation (NRF) Chair in Shallow Water Ecosystems with Professor Perissinotto and Dr Nelson Miranda as supervisors. She is now pursuing further investigations on the complex interactions between native and alien species, including molecular genetic tests of potentially interbreeding populations.  

Raw identified Dr Sylvia Earle, the National Geographic Explorer-in-Residence, as an inspirational influence and also thanked her supervisors, Perissinotto and Miranda, for their continuous support throughout the course of the project. ‘I would not have been able to complete my Masters without the funding I received from UKZN and the National Research Fund (NRF), for which I am very grateful. I would also like to thank my family for their never-ending encouragement and my dear friend and colleague Nasreen Peer for all her advice and assistance.’  

-                     Leena Rajpal