Re ECF Project: ECF 2015-32

Project Title: Distribution and ecological impacts of invasive ant species on arthropod communities in Hong Kong

Applicant: Dr Benoit Guénard, School of Biological Sciences, The University of Hong Kong

Total Approved Grant: $500,000

Duration: 1/5/2016 to 30/4/2018

Project Status/Remarks: Completed

Several exotic and invasive ant species have been reported in Hong Kong but their actual number and ecological impacts are unknown. This project aims to carry out a survey to establish distribution maps of non-native species in Hong Kong around and within several Country Parks. Based on previous results, the ecological impacts of the Red Imported Fire Ant (Solenopsis invicta) and the Yellow Crazy Ant (Anoplolepis gracilipes) on native ant communities will be studied. The project will propose an experiment to evaluate the ecological impacts of S. invicta on decomposition processes and on the decomposer guild of arthropods. It will provide a better understanding of the threats on the native fauna in Hong Kong from non-native ant species introduction and will help for the management of their populations.

Summary of the Findings/Outcomes:
The research team achieved a better understanding of the distributions of native and non-native ant species across Hong Kong, evaluated the ecological impact of two invasive species (Solenopsis invicta and Anoplolepis gracilipes), increased knowledge of patterns of ant biodiversity in Hong Kong, and discovered several species potentially new to science. Four invasive ant species are widespread throughout Hong Kong, and can be locally very abundant in certain areas. One of these, Solenopsis invicta is associated with a large and significant reduction of native ant diversity; another widespread invasive species, Anoplolepis gracilipes, was associated with a smaller but nonetheless significant negative impact on native species. The research team also found that ants are major contributors to the decomposition process, with the highest rates observed in the presence of Solenopsis invicta. Overall, Solenopsis invicta is associated with significant changes in the environment, and further research can be invested to determine the extent of its effects. The research team also uncovered several rare and newly recorded species for Hong Kong with potentially four species new to science to be described. Results from the project were presented at the “2018 Invasive Ant Conference” in Kyoto, Japan and at a seminar held in The University of Hong Kong.